Article: 214698 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Modeling TL "dielectric" loss Date: Fri, 1 Jul 2005 04:54:35 +0000 (UTC) Message-ID: References: "Owen" > Any thoughts. Is there an inconsistency between the explanation that G > is principally due to D of the dielectric material, or I have I messed > the maths up? > > Owen =================================== >From where did you obtain D 2e-3 for RG 58 ? That's the most likely source of the discrepancy. Also the highest grade polyethylene is unlikely to be used for the manufacture of RG58. The only way to investigate is to lay 100 feet on the ground, in the form of a circle, and measure attenuation vs frequency between the ends from 1 MHz to 1 GHz. --- Reg Article: 214699 of rec.radio.amateur.antenna From: Owen Subject: Re: Modeling TL "dielectric" loss Message-ID: References: Date: Fri, 01 Jul 2005 05:14:36 GMT On Fri, 1 Jul 2005 04:54:35 +0000 (UTC), "Reg Edwards" wrote: > >"Owen" >> Any thoughts. Is there an inconsistency between the explanation that >G >> is principally due to D of the dielectric material, or I have I >messed >> the maths up? >> >> Owen >=================================== > >From where did you obtain D 2e-3 for RG 58 ? That's the most likely >source of the discrepancy. > >Also the highest grade polyethylene is unlikely to be used for the >manufacture of RG58. > >The only way to investigate is to lay 100 feet on the ground, in the >form of a circle, and measure attenuation vs frequency between the >ends from 1 MHz to 1 GHz. I took the figures published by Belden for their 8262 cable at frequencies from 1MHx to 1Gz (9 points) and did a polynomial regression to MLL=k1*f**0.5+k2*f, then substituted k2 into the expression described in my original post. I didn't measure the losses, and I recognise that Belden might have smoothed their results by an intermediate regression, but I figure that they are not going to exaggerate the effect of k2 unnecessarily. Owen -- Article: 214700 of rec.radio.amateur.antenna Message-ID: <42C4D8E7.8E99D9B2@theforce.com> From: luke Subject: Re: 6 Meter Antenna References: Date: Fri, 01 Jul 2005 05:47:21 GMT hi james, Save your money, you can build this one for under $ 10, even less if you have some 1/2 " pvc and #12 thhn wire in the shop ! http://www.cebik.com/moxon/6m.html Moxon for 6m, use it vertical for FM/Repeaters or horizontal for ssb and cw. Smaller then a 2 element yagi but almost the same gain ! 73 luke "James F. Mayer" wrote: > What is a good commercially available antenna for 6 meters. I have an > RT-70A/GRC that I'm getting ready to power up in a couple of weeks. Would > my discone suffice? Article: 214701 of rec.radio.amateur.antenna From: "Mark" References: Subject: Re: Radial Pattern For Vertical Antenna Message-ID: Date: Thu, 30 Jun 2005 23:32:54 -0700 Thanks for the input. I will check out the QEX article. The fence is block and my "neighbor's yard" is a horse exercise pasture. The horse farm behind me breeds and trains race horses. Mark, KJ7BS "'Doc" wrote in message news:YL3xe.5009$RC6.1256@newssvr33.news.prodigy.com... > Mark, > Good question! There will be ~some~ gain/loss of signal in > various directions. Probably won't be much gain or loss, > just depends on 'other' things (how near the fence, fence made > of wood/metal, and other mysterious things). Wouldn't worry > too much about it, and if it really bothers you, sneak a radial > or two under the fence for a ways. Hide it well and don't get > caught running stuff in your neighbor's yard! > 'Doc Article: 214702 of rec.radio.amateur.antenna From: jcooper874@webtv.net Subject: Re: 6 Meter Antenna Date: Fri, 1 Jul 2005 03:34:53 -0500 Message-ID: <512-42C5002D-397@storefull-3274.bay.webtv.net> References: <42C4D8E7.8E99D9B2@theforce.com> i bet the moxon will make a good tv antenna Article: 214703 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Modeling TL "dielectric" loss Date: Fri, 01 Jul 2005 02:25:29 -0700 Message-ID: <11ca30a2op8obba@corp.supernews.com> References: Owen wrote: > > I took the figures published by Belden for their 8262 cable at > frequencies from 1MHx to 1Gz (9 points) and did a polynomial > regression to MLL=k1*f**0.5+k2*f, then substituted k2 into the > expression described in my original post. > > I didn't measure the losses, and I recognise that Belden might have > smoothed their results by an intermediate regression, but I figure > that they are not going to exaggerate the effect of k2 unnecessarily. I didn't realize that was the source of your loss figures. Reg is right, you have to measure it. Another thing I found long ago is that the published specs don't match reality. I recall finding Belden to be conservative with loss, but that sure isn't the case with some others. I just had occasion to very carefully measure the loss of some Davis RF "Bury-Flex" which they specify as having 2.9 dB/100' at 400 MHz. It was 4.1 dB/100' at 400 MHz and extrapolated very nicely to at least 3.5 MHz with a square root rule. (It has a solid aluminum shield under the copper.) So there's some real specsmanship going on out there. Roy Lewallen, W7EL Article: 214704 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Modeling TL "dielectric" loss Date: Fri, 01 Jul 2005 02:29:31 -0700 Message-ID: <11ca37rthiqui46@corp.supernews.com> References: <1120201685.960902.270000@g43g2000cwa.googlegroups.com> One other thing I did long ago was to check some semi-rigid lines with solid shield and center conductor and PTFE dielectric, against theoretical calculations. As I recall, the agreement was pretty good -- much better than the garden variety coax. And by the way, you'll see a noticeable difference in loss between RG-58, which has a solid copper center conductor, and RG-58A which is tinned -- as you'd expect. Roy Lewallen, W7EL K7ITM wrote: > My reference suggests that D for PE is 2e-4, but even at that, the > copper loss would be ten times the dielectric loss out to 2GHz, if I > figured it right. It could be difficult to accurately determine your > k2 with such a small contribution from the dielectric. But there are > likely other mechanisms at work... > > Roy mentioned the braid. I recall reading a nice article by, I > believe, an engineer with Andrew talking about various loss mechanisms > in coax due to things like braid and stranded inner conductor and > surface smoothness. The article went well beyond the usual theoretical > discussion that assumes smooth conductors and perfectly uniform > construction. I wish I could locate it again! I thought it was in "RF > Design" magazine, but never could find it again there, so perhaps it > was in "Electronic Design" or "EDN". > > One mechanism to consider is the effects of a non-constant Zo as a > function of distance along the line. There are undoubtedly small > variations in the manufacturing process. Over a length of line that's > many wavelengths long, even small variations make a noticable > difference. It's not a dissipative mechanism, per se, but will show up > as line attenuation if you put the line on a network analyzer. Small, > flexible lines that are guaranteed to a close tolerance on impedance > are quite expensive. > > I don't claim to have any definitive answers for this one, but hope my > comments give you some ideas where to look. > > Cheers, > Tom > Article: 214705 of rec.radio.amateur.antenna From: W9DMK (Robert Lay) Subject: Re: Can U solve this? Date: Fri, 01 Jul 2005 11:48:19 GMT Message-ID: <42c52cb7.5297136@news.crosslink.net> References: <42c43383$1_1@spool9-west.superfeed.net> On Thu, 30 Jun 2005 12:57:02 -0500, Cecil Moore wrote: >It would be interesting to find out who, among the >experts on this group, cannot solve this problem >for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, >Vref2, Iref2 including magnitudes and phase >angles. > >Given: a Z0-match at an impedance discontinuity in >a transmission line. Source is unknown. Load is >unknown. Lengths of transmission lines are unknown. >Reference phase: Vfwd1 is incident upon the Z0-match >at a reference phase angle of zero degrees. > >---50 ohm feedline---+---200 ohm feedline--- > Pfwd1=100w--> Pfwd2=156.25w--> > <--Pref1=0w <--Pref2=56.25w > >Contrary to what some people assert, is it possible >to calculate the magnitudes and phases of the >above voltages and currents knowing only the >Z0's and the forward and reflected powers? You probably won't find many people who would even recognize how to approach the problem. But there will be 10X that many who feel free to tell you why they think the whole thing is nonsense. What do you suppose that syndrome should be called - "burying one's head in the sand?" Bob, W9DMK, Dahlgren, VA Replace "nobody" with my callsign for e-mail http://www.qsl.net/w9dmk http://zaffora/f2o.org/W9DMK/W9dmk.html Article: 214706 of rec.radio.amateur.antenna Date: Fri, 01 Jul 2005 07:20:22 -0500 From: Cecil Moore Subject: Re: Antenna Tuner for 20m Dipole - Build References: <42c5265f@news.iconz.co.nz> Message-ID: <42c53602$1_1@spool9-west.superfeed.net> Kevin & Natalia wrote: > Hi All, > > I have just built a 20m dipole as a temp antenna for home. > I will be driving it with a TS-830 transceiver, which uses valves in the > final stage. > I know that I can only use it close to the cut frequency, but want to build > a small tuner to allow me to go off the cut slightly. > I only want the tuner to be used on 20m, so I do not need any coil tapings > for switching bands, so maybe a couple of caps will do the job. > > Look forward to any replies. Regards Kevin, ZL1KFM. Hi Kevin, feed it with 450 ohm ladder-line. Make the ladder-line length an integer number of 1/2 wavelengths. Then you can tune your antenna system to resonance without a tuner by adding one foot of ladder-line for lower frequency operation and subtracting one foot for higher frequency operation. Varying the length of the ladder-line by 0, 1, or 2 feet should cover the entire 20m band. My resonant frequencies are 0' = 14.34 MHz; 1' = 14.2 MHz; 2' = 14.1 MHz. Of course, it doesn't have to be in one foot increments. 35 cm increments might be better. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214707 of rec.radio.amateur.antenna From: "Dale Parfitt" References: <42c5265f@news.iconz.co.nz> Subject: Re: Antenna Tuner for 20m Dipole - Build Message-ID: Date: Fri, 01 Jul 2005 12:35:37 GMT "Kevin & Natalia" wrote in message news:42c5265f@news.iconz.co.nz... > Hi All, > > I have just built a 20m dipole as a temp antenna for home. > I will be driving it with a TS-830 transceiver, which uses valves in the > final stage. > I know that I can only use it close to the cut frequency, but want to build > a small tuner to allow me to go off the cut slightly. > I only want the tuner to be used on 20m, so I do not need any coil tapings > for switching bands, so maybe a couple of caps will do the job. > > Look forward to any replies. > > Regards > > Kevin, ZL1KFM. > > Hi Kevin, The 830 already has a tuner built into it- the Pi network output circuit. When you go through the tune/load procedure you are marching the 830's output to the load. To put another tuner on the output would be redundant. Dale W4OP Article: 214708 of rec.radio.amateur.antenna Date: Fri, 01 Jul 2005 07:45:29 -0500 From: Cecil Moore Subject: Re: Can U solve this? References: <42c43383$1_1@spool9-west.superfeed.net> <42c52cb7.5297136@news.crosslink.net> Message-ID: <42c53be5$1_1@spool9-west.superfeed.net> W9DMK (Robert Lay) wrote: > Cecil Moore wrote: >>It would be interesting to find out who, among the >>experts on this group, cannot solve this problem >>for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, >>Vref2, Iref2 including magnitudes and phase >>angles. >> >>Given: a Z0-match at an impedance discontinuity in >>a transmission line. Source is unknown. Load is >>unknown. Lengths of transmission lines are unknown. >>Reference phase: Vfwd1 is incident upon the Z0-match >>at a reference phase angle of zero degrees. >> >>---50 ohm feedline---+---200 ohm feedline--- >> Pfwd1=100w--> Pfwd2=156.25w--> >> <--Pref1=0w <--Pref2=56.25w >> >>Contrary to what some people assert, is it possible >>to calculate the magnitudes and phases of the >>above voltages and currents knowing only the >>Z0's and the forward and reflected powers? > > You probably won't find many people who would even recognize how to > approach the problem. The ones who assert that it is impossible can't even afford to try. If they can't solve it, they look ignorant. If they solve it, they lose the argument about it being impossible to solve. Incidentally, I made it easier than necessary. Pfwd2 doesn't have to be given. The joules/sec into a lossless impedance discontinuity have to equal the joules/sec out so if three of the above four joules/sec values are known, the fourth can be calculated. > But there will be 10X that many who feel free to tell you why they > think the whole thing is nonsense. What do you suppose that syndrome > should be called - "burying one's head in the sand?" How about "burying one's head where the sun don't shine"? :-) (Sorry, the devil made me say that.) I find it interesting that the people who say they don't care where the energy goes respond with a gut feeling and ad hominem attack when anyone mentions the subject. If physicists can track a single photon, surely we hams can track the energy in EM waves. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214709 of rec.radio.amateur.antenna From: Sonny Hood Subject: Mosley Pro57A Beam Message-ID: Date: Fri, 01 Jul 2005 10:23:11 -0400 Mosley Pro 57A HF Beam, 5 Band 20-10 Meters 8.5 dbd 20-12M, 9.4 dbd on 10M, w/ 24 Ft. Boom. Ready for pickup, on the ground. $ 50.00/ OBO Pickup Southeast Virginia. k4wys@cox.net Article: 214710 of rec.radio.amateur.antenna From: Sonny Hood Subject: FS/Pickup Rohn 25G Message-ID: <1gkac1pi8hq9e321j7lovqtdrqs7rapv1r@4ax.com> Date: Fri, 01 Jul 2005 10:26:14 -0400 60 Ft. Rohn 25G Tower (5-10 FT. sections & 1-9 Ft. Top section w/ AS25 Rotor Plate) very good condition NO RUST. [Plus a 48" Section for concrete base install] All is on the ground ready for pickup. $250.00 Pickup Southeast Virginia k4wys@cox.net Article: 214711 of rec.radio.amateur.antenna From: Sonny Hood Subject: Rohn House Bracket Message-ID: Date: Fri, 01 Jul 2005 10:28:11 -0400 HB25GA House Bracket for Rohn 25G tower (ready for pickup) $ 25.00 Pickup Southeast Virginia. k4wys@cox.net Article: 214712 of rec.radio.amateur.antenna Date: Fri, 01 Jul 2005 10:18:41 -0500 From: Cecil Moore Subject: Re: FS/Pickup Rohn 25G References: <1gkac1pi8hq9e321j7lovqtdrqs7rapv1r@4ax.com> Message-ID: <42c55fe8$1_2@spool9-west.superfeed.net> Sonny Hood wrote: > 60 Ft. Rohn 25G Tower (5-10 FT. sections & 1-9 Ft. Top section w/ AS25 > Rotor Plate) very good condition NO RUST. [Plus a 48" Section for > concrete base install] All is on the ground ready for pickup. > $250.00 Pickup Southeast Virginia k4wys@cox.net 30 ft. Rohn 25G free for pickup one mile from I45 off TX Hwy 21 in Madisonville, TX. Email if interested. -- 73, Cecil, http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 214713 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <42C4D8E7.8E99D9B2@theforce.com> <512-42C5002D-397@storefull-3274.bay.webtv.net> Subject: Re: 6 Meter Antenna Date: Fri, 1 Jul 2005 11:24:28 -0400 Message-ID: <8da9d$42c5602f$97d55b49$8400@ALLTEL.NET> Bet it won't, unless your only interested in 1 channel or are in an area of vary strong signals where it dosn't matter what you use. wrote in message news:512-42C5002D-397@storefull-3274.bay.webtv.net... > i bet the moxon will make a good tv antenna > Article: 214715 of rec.radio.amateur.antenna From: Bob Dixon Subject: Re: Correct cable for 920Mhz Mobile, Yagi Date: Fri, 01 Jul 2005 12:28:10 -0400 Message-ID: References: <0op0c1d8g1l9d4nku27v1nt8oroal2i1u1@4ax.com> <1dIwe.5942$ho.5388@bignews6.bellsouth.net> Could you provide any references to the successful use of passive repeaters? I tried it once and it was a flop. Bob W8ERD In article <1dIwe.5942$ho.5388@bignews6.bellsouth.net>, "Hal Rosser" wrote: > Remember, the high gain antenna will have a narrow beam, > The phone companies have used passive repeaters with good success. > > > "Mark" wrote in message > news:0op0c1d8g1l9d4nku27v1nt8oroal2i1u1@4ax.com... > > On Sat, 25 Jun 2005 17:40:50 -0400, "Hal Rosser" > > wrote: > > > > >This may well be an application for a passive repeater. > > >2 yagis back to back > > >one aimed at the nearest tower > > >the other aimed at your house. > > >mount it high > > > > That sounds like a good idea, should I mount the antenna's at a 90o > > angle relative to each other, with the receiving antenna mounted to > > look in the vertical plane (I know where the base station is). And the > > transmitting antenna to give as much horizontal plane coverage as > > possible, angled down to the areas I wish to receive telephone > > coverage? Can I expect good results? Article: 214716 of rec.radio.amateur.antenna From: John Ferrell Subject: Rotate TriBand to vertical? Message-ID: Date: Fri, 01 Jul 2005 19:26:56 GMT I have a Cushcraft A3 beam on a crank up/tilt over tower. When I tilt it over, it still requires a ladder to work on it due to the length of the elements. What I would like to do is to be able to rotate it as though I were trying for vertical polarization before or during the tilt over process. That would bring the antenna to a "flat" attitude for maintenance and storm protection. Any thoughts? The usual old fashioned Ham parameters apply: Little cost as possible, build as much as I can my self, etc...... BTW, I have several good TV rotators I might use, but none with a hole all the way through! de W8CCW Article: 214717 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <42c5265f@news.iconz.co.nz> Subject: Re: Antenna Tuner for 20m Dipole - Build Date: Fri, 1 Jul 2005 11:36:14 -0400 Message-ID: <8900a$42c59cef$97d55b49$22714@ALLTEL.NET> How about just a couple of relays? If you have some 300 ohm or 450 ohm feedline available, I can give you a simple solution. E-mail me at w4jle@w4jle.com "Kevin & Natalia" wrote in message news:42c5265f@news.iconz.co.nz... > Hi All, > > I have just built a 20m dipole as a temp antenna for home. > I will be driving it with a TS-830 transceiver, which uses valves in the > final stage. > I know that I can only use it close to the cut frequency, but want to build > a small tuner to allow me to go off the cut slightly. > I only want the tuner to be used on 20m, so I do not need any coil tapings > for switching bands, so maybe a couple of caps will do the job. > > Look forward to any replies. > > Regards > > Kevin, ZL1KFM. > > Article: 214718 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 16:16:47 -0400 (I have tried unsuccessfully to make the tabular data in the msg below come out correctly. I apologize for that and hope you can interpret the data successfully. Walt,W2DU) Thanks to Richard Harrison, he has supplied us with the renowned Brown, Lewis and Epstein paper, reporting the voluminous and enlightening experimental data concerning the length and number of ground radials required in approaching the condition of perfect ground underneath a vertical radiator. This paper has long been well known and highly respected in the communications engineering community, and since 1938 has become the standard for engineering the radial systems for AM BC stations Worldwide. The FCC requirement for radials in US BC stations is based on data in the BLE paper. The tragedy here is that BLE paper has gone practically unknown in the amateur community, as witnessed by so many continual questions and incorrect answers concerning the length and number of radials required to achieve the desired performance of our vertical radiators. So let me present a short, but definitive abstract of the pertinent numbers taken from the paper, that answer some of the pertinent questions correctly. As a reference on which to base the radiated field strength, the industry standard has traditionally used millivolts per meter to describe field strength. Specifically, the field strength of 194.5 millivolts per meter at one mile, radiated from a quarter-wavelength radiator over perfect ground with 1000 watts input, is the industry standard. In other words, this field strength is the maximum attainable under ideal conditions. The data below, obtained directly >from measurements made at 3 MHz by Brown, Lewis and Epstein in 1937, provide definitive answers to those who ask how many radials of what length are necessary to provide a suitable ground plane. When comparing the fields strengths below, remember that 194.5 mv/meter is the field strength obtained with perfect lossless ground. Number of Field Strength Loss in dB Relative Radials in mv/meter to Perfect Ground Length Length 0.4 wl 1/4 wl 1/8 wl 0.4 wl 1/4 wl 1/8 wl 113 192 180 152 0.112 0.673 2.14 60 185 176 150 0.435 0.868 2.26 30 174 162 150 0.967 1.59 2.26 15 158 153 1.81 2.08 2 126 120 118 3.77 4.19 4.39 When reviewing these data, please keep in mind that as the field strength approaches 194.5 mv/meter the effective ground is approaching perfect ground, which means that the conductivity of the ground in which the radials are planted is irrelevant, only the ground external to the radial system is relevant with respect to conductivity. It should also be kept in mind that the energy in the EM fields surrounding the vertical radiator diminishes with distance from the radiator. Thus the displacement currents entering the ground diminish proportionately with distance. Consequently, there is a distance from the radiator after which the currents become too small to be significant to the conservation of power radiated. This fact determines the maximum length of the radials necessary to reach the point where the law of diminishing returns prevails. The measurements reported in the BLE paper show this distance to be between 0.4 and 0.5 wavelengths. As noted above, this distance is relative to the amount of energy in the displacement currents at this distance from the radiator, and is in no way relevant to any resonant length of the radial. It is well known that radials buried in the ground lose all sense of resonance. Walt, W2DU Article: 214719 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <5LKdndjiyKqwAlnfRVn-hw@comcast.com> Subject: Re: Radial Pattern For Vertical Antenna Message-ID: <7Nhxe.3458$iv3.990@fe02.lga> Date: Fri, 1 Jul 2005 16:34:08 -0400 I have read Al Christman's QEX article, and though he mentions radial systems used in AM BC stations, I doubt if he's read Brown, Lewis and Epstein, else I also doubt if he would have made some of the statements that appear in the article The Brown, Lewis and Epstein paper is a must read for anyone contemplating the installation of radials for a vertical radiator. Fortunately, Richard Harrison has supplied the paper in the thread below 'Brown Lewis and Epstein'. My post below has also been added to the above mentioned thread. However, I apologize for the problem in making the tabular data come out right--I tried, but was unsuccessful, so I hope you can interpret the data to be useful to you. Now to the mail I posted in the above mentioned thread. Walt,W2DU Thanks to Richard Harrison, he has supplied us with the renowned Brown, Lewis and Epstein paper, reporting the voluminous and enlightening experimental data concerning the length and number of ground radials required in approaching the condition of perfect ground underneath a vertical radiator. This paper has long been well known and highly respected in the communications engineering community, and since 1938 has become the standard for engineering the radial systems for AM BC stations Worldwide. The FCC requirement for radials in US BC stations is based on data in the BLE paper. The tragedy here is that BLE paper has gone practically unknown in the amateur community, as witnessed by so many continual questions and incorrect answers concerning the length and number of radials required to achieve the desired performance of our vertical radiators. So let me present a short, but definitive abstract of the pertinent numbers taken from the paper, that answer some of the pertinent questions correctly. As a reference on which to base the radiated field strength, the industry standard has traditionally used millivolts per meter to describe field strength. Specifically, the field strength of 194.5 millivolts per meter at one mile, radiated from a quarter-wavelength radiator over perfect ground with 1000 watts input, is the industry standard. In other words, this field strength is the maximum attainable under ideal conditions. The data below, obtained directly >from measurements made at 3 MHz by Brown, Lewis and Epstein in 1937, provide definitive answers to those who ask how many radials of what length are necessary to provide a suitable ground plane. When comparing the fields strengths below, remember that 194.5 mv/meter is the field strength obtained with perfect lossless ground. Number of Field Strength Loss in dB Relative Radials in mv/meter to Perfect Ground Length Length 0.4 wl 1/4 wl 1/8 wl 0.4 wl 1/4 wl 1/8 wl 113 192 180 152 0.112 0.673 2.14 60 185 176 150 0.435 0.868 2.26 30 174 162 150 0.967 1.59 2.26 15 158 153 1.81 2.08 2 126 120 118 3.77 4.19 4.39 When reviewing these data, please keep in mind that as the field strength approaches 194.5 mv/meter the effective ground is approaching perfect ground, which means that the conductivity of the ground in which the radials are planted is irrelevant, only the ground external to the radial system is relevant with respect to conductivity. It should also be kept in mind that the energy in the EM fields surrounding the vertical radiator diminishes with distance from the radiator. Thus the displacement currents entering the ground diminish proportionately with distance. Consequently, there is a distance from the radiator after which the currents become too small to be significant to the conservation of power radiated. This fact determines the maximum length of the radials necessary to reach the point where the law of diminishing returns prevails. The measurements reported in the BLE paper show this distance to be between 0.4 and 0.5 wavelengths. As noted above, this distance is relative to the amount of energy in the displacement currents at this distance from the radiator, and is in no way relevant to any resonant length of the radial. It is well known that radials buried in the ground lose all sense of resonance. Walt, W2DU Article: 214720 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <5LKdndjiyKqwAlnfRVn-hw@comcast.com> <7Nhxe.3458$iv3.990@fe02.lga> Subject: Re: Radial Pattern For Vertical Antenna Message-ID: <96ixe.3460$iv3.274@fe02.lga> Date: Fri, 1 Jul 2005 16:56:32 -0400 Man, O, Man, do I have some apologizing to do to Danny Richardson, K6JHE. Danny is the one who supplied the data on the Brown, Lewis and Epstein paper, not Richard Harrison. I'm sorry, Danny, it was a senior moment at age 86 that's responsible. Walt, W2DU Article: 214721 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 16:57:19 -0400 Man, O, Man, do I have some apologizing to do to Danny Richardson, K6JHE. Danny is the one who supplied the data on the Brown, Lewis and Epstein paper, not Richard Harrison. I'm sorry, Danny, it was a senior moment at age 86 that's responsible. Walt, W2DU Article: 214722 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 17:32:27 -0400 "Fred W4JLE" wrote in message news:4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET... > Walt, while this would be wonderful information if I were broadcasting > during the day on 75 meters, how is it applicable to those of us who don't > care about groundwave? Well, Fred, it's because it has everything to do with how much of your xmtr power is heating the ground vs how much is being radiated at whatever frequency you're using. We're not even talking about ground wave, it's how much power is radiated, period. Walt Article: 214723 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 17:33:28 -0400 "Fred W4JLE" wrote in message news:4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET... > Walt, while this would be wonderful information if I were broadcasting > during the day on 75 meters, how is it applicable to those of us who don't > care about groundwave? Well, Fred, it's because it has everything to do with how much of your xmtr power is heating the ground vs how much is being radiated at whatever frequency you're using. We're not even talking about ground wave, it's how much power is radiated, period. Walt Article: 214724 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 17:33:41 -0400 "Fred W4JLE" wrote in message news:4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET... > Walt, while this would be wonderful information if I were broadcasting > during the day on 75 meters, how is it applicable to those of us who don't > care about groundwave? Well, Fred, it's because it has everything to do with how much of your xmtr power is heating the ground vs how much is being radiated at whatever frequency you're using. We're not even talking about ground wave, it's how much power is radiated, period. Walt Article: 214725 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> Subject: Re: Brown, Lewis & Epstein Message-ID: <9Fixe.22432$B_3.4024@fe05.lga> Date: Fri, 1 Jul 2005 17:33:56 -0400 "Fred W4JLE" wrote in message news:4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET... > Walt, while this would be wonderful information if I were broadcasting > during the day on 75 meters, how is it applicable to those of us who don't > care about groundwave? Well, Fred, it's because it has everything to do with how much of your xmtr power is heating the ground vs how much is being radiated at whatever frequency you're using. We're not even talking about ground wave, it's how much power is radiated, period. Walt Article: 214726 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 17:39:40 -0400 "Walter Maxwell" wrote in message news:S6ixe.3461$iv3.806@fe02.lga... > Man, O, Man, do I have some apologizing to do to Danny Richardson, K6JHE. > Danny is the one who supplied the data on the Brown, Lewis and Epstein paper, > not Richard Harrison. > > I'm sorry, Danny, it was a senior moment at age 86 that's responsible. > > Walt, W2DU Dang, I can't seem to get anything right today. Can't even spell Danny's call sign correctly. Repeat after me, it's K6MHE, it's K6MHE, it's K6MHE. Walt, W2DU > > Article: 214727 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> <9Fixe.22432$B_3.4024@fe05.lga> Subject: Re: Brown, Lewis & Epstein Message-ID: <%Lixe.22434$B_3.15145@fe05.lga> Date: Fri, 1 Jul 2005 17:41:12 -0400 Sorry about the multiple postings above. My moronic computer told me each time that the msg could not be sent, so I kept trying. Walt, W2DU Article: 214728 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <5LKdndjiyKqwAlnfRVn-hw@comcast.com> <7Nhxe.3458$iv3.990@fe02.lga> <96ixe.3460$iv3.274@fe02.lga> Subject: Re: Radial Pattern For Vertical Antenna Message-ID: Date: Fri, 1 Jul 2005 17:44:57 -0400 "Walter Maxwell" wrote in message news:96ixe.3460$iv3.274@fe02.lga... > Man, O, Man, do I have some apologizing to do to Danny Richardson, K6JHE. > Danny is the one who supplied the data on the Brown, Lewis and Epstein paper, > not Richard Harrison. > > I'm sorry, Danny, it was a senior moment at age 86 that's responsible. > > Walt, W2DU Dang, I can't seem to get anything right today. Can't even spell Danny's call sign correctly. Repeat after me, it's K6MHE, it's K6MHE, it's K6MHE. Walt, W2DU Article: 214729 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Brown, Lewis & Epstein Date: Fri, 01 Jul 2005 15:01:31 -0700 Message-ID: <11cbf9t914nd90c@corp.supernews.com> References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> Maybe this will help clarify it. . . As Walt and Danny said, this is all about efficiency -- the fraction of your applied power that gets used heating the ground. So the ground wave and sky wave are reduced by the same fraction. Just look at those dB values in the right hand column of Walt's summary, and they'll apply to 75 meter sky wave as well as to ground wave. They won't be exact, of course, since they depend on both ground characteristics (to quite a fair depth) and frequency. But they're as good a set of working values as you'll find. Roy Lewallen, W7EL Dan Richardson arrl wrote: > On Fri, 1 Jul 2005 17:12:44 -0400, "Fred W4JLE" > wrote: > > >>Walt, while this would be wonderful information if I were broadcasting >>during the day on 75 meters, how is it applicable to those of us who don't >>care about groundwave? >> > > I think you may have miss the point Fred... Its about antenna > efficiency. > > Danny, > K6MHE > Article: 214730 of rec.radio.amateur.antenna From: "Richard Fry" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> Subject: Re: Brown, Lewis & Epstein Date: Fri, 1 Jul 2005 17:12:58 -0500 Message-ID: <42c5c04a_4@newsfeed.slurp.net> "Walter Maxwell" wrote: > When reviewing these data, please keep in mind that as the field strength > approaches 194.5 mv/meter the effective ground is approaching perfect > ground, which means that the conductivity of the ground in which the > radials are planted is irrelevant, only the ground external to the radial > system is relevant with respect to conductivity. BL&E measured the groundwave field strength generated by a 200 milliwatt carrier 0.3 miles from a vertical radiator. This value was converted to equivalent field for 1 kW of radiated power at a distance of 1 mile. With this technique, and with 113 each 0.412-wave radials, they found that their measured/converted field was less than 0.1124 dB below the theoretical value for it over a perfect ground plane. These results demonstrate that the consideration of ground conductivity during this study over this short path was unnecessary (REG, please note). > It should also be kept in mind that the energy in the EM fields > surrounding the vertical radiator diminishes with distance from the > radiator. Thus the displacement currents entering the ground diminish > proportionately with distance. Consequently, there is a distance from the > radiator after which the currents become too small to be significant to > the conservation of power radiated. This fact determines the maximum > length of the radials necessary to reach the point where the law of > diminishing returns prevails. The measurements reported in the BLE paper > show this distance to be between 0.4 and 0.5 wavelengths. And that was for 113 radials. If only a few radials are used, BL&E report that it is pointless to extend them that far. RF Article: 214731 of rec.radio.amateur.antenna Date: Fri, 01 Jul 2005 18:18:50 -0500 From: Cecil Moore Subject: Re: Can U solve this? References: <42c43383$1_1@spool9-west.superfeed.net> <1120250032.104926.109260@g14g2000cwa.googlegroups.com> Message-ID: <42c5d056$1_1@spool9-west.superfeed.net> K7ITM wrote: > I've just been ignoring it till now, to see what sort of raging > arguments would start. But is it supposed to be difficult?? According to some experts on this newsgroup, a pure energy analysis is "gobbledegook" (sic) at best and impossible at worst. One should avoid an energy (power) analysis at all costs and deal only with voltages and currents until the very end of the analysis. It is ridiculous to try to track the energy inside a transmission line and any attempt to do so is stupid and doomed to failure because reflected waves of energy don't really exist. Standing waves have an independent existence all their own and do not require a forward traveling energy wave and a rearward traveling energy wave. The extra energy stored in a transmission line with reflections just "sloshes" around presumably from side to side. I could continue but hopefully, you get the idea. Incidentally, Walter Maxwell doesn't seem to have had any trouble at all tracking energy (power) in _Reflections_I & II. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 214732 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 19:38:00 -0400 "Richard Fry" wrote in message news:42c5c04a_4@newsfeed.slurp.net... > "Walter Maxwell" wrote: >> When reviewing these data, please keep in mind that as the field strength >> approaches 194.5 mv/meter the effective ground is approaching perfect ground, >> which means that the conductivity of the ground in which the radials are >> planted is irrelevant, only the ground external to the radial system is >> relevant with respect to conductivity. > > BL&E measured the groundwave field strength generated by a 200 milliwatt > carrier 0.3 miles from a vertical radiator. This value was converted to > equivalent field for 1 kW of radiated power at a distance of 1 mile. With > this technique, and with 113 each 0.412-wave radials, they found that their > measured/converted field was less than 0.1124 dB below the theoretical value > for it over a perfect ground plane. These results demonstrate that the > consideration of ground conductivity during this study over this short path > was unnecessary (REG, please note). > >> It should also be kept in mind that the energy in the EM fields surrounding >> the vertical radiator diminishes with distance from the radiator. Thus the >> displacement currents entering the ground diminish proportionately with >> distance. Consequently, there is a distance from the radiator after which the >> currents become too small to be significant to the conservation of power >> radiated. This fact determines the maximum length of the radials necessary to >> reach the point where the law of diminishing returns prevails. The >> measurements reported in the BLE paper show this distance to be between 0.4 >> and 0.5 wavelengths. > > And that was for 113 radials. If only a few radials are used, BL&E report > that it is pointless to extend them that far. > > RF Correct on both counts, Richard, thanks for reminding Reg, I forgot to. Did I mention that I had the privilege of working at Brown's RCA antenna lab along side Epstein for several years? Bob Lewis had left RCA when I arrived, but I knew him later as a ham, W2EBS. Walt, W2DU Article: 214733 of rec.radio.amateur.antenna From: Owen Subject: Re: Modeling TL "dielectric" loss Message-ID: References: <1120201685.960902.270000@g43g2000cwa.googlegroups.com> <11ca37rthiqui46@corp.supernews.com> Date: Fri, 01 Jul 2005 23:56:35 GMT On Fri, 01 Jul 2005 02:29:31 -0700, Roy Lewallen wrote: >One other thing I did long ago was to check some semi-rigid lines with >solid shield and center conductor and PTFE dielectric, against >theoretical calculations. As I recall, the agreement was pretty good -- >much better than the garden variety coax. > Ok, that is one of the reasons that I looked at how k2 changed with size of the LDF series. I have just had a look at LMR200 wrt LMR1700. (They have an aluminium tape +braid outer.) I do not know the value of D for the closed cell foam dielectric that they use. The k2 factor (and therefore G) of the larger cable is about 50% of the smaller cable, though there is nearly a 1100% increase in diameter. It seems that of the few cables that I have looked at that ones with better shielding result in less variation in k2 (and G) with change in diameter ( for Zo and dielectric remaining constant). That suggests that shielding and loss effectiveness of the outer conductor is to some extent reflected in G (proportional to f). Tom, the D figure I quoted for PE was from the ITT Radio Engineers Handbook. G seems not to be solely or principally dependendent on D of the dielectric in a general sense. It may be with very good lines, but it doesn't seem to be so with single braided PE insulated coax. It is clear that using D (even at 2e-4) to calculate G in an RLGC model of R58C/U will not give a very good fit to published attenuation characteristics. Regarding using the published specs, I am trying to glean as much as is reasonable from the published specs. I note and agree with your comment Roy about the quality or accuracy of some specs. Thanks all for the thoughts on possible contributions to G. Owen -- Article: 214734 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> Subject: Re: Brown, Lewis & Epstein Date: Fri, 1 Jul 2005 20:56:27 -0400 Message-ID: <4bb90$42c5e63d$97d55b49$11166@ALLTEL.NET> So as I understand it, as I add more radials, my field strength should increase regardless of the elevation angle. Assuming I make all measurements at the same point. "Walter Maxwell" wrote in message news:JEixe.22429$B_3.22179@fe05.lga... > > "Fred W4JLE" wrote in message > news:4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET... > > Walt, while this would be wonderful information if I were broadcasting > > during the day on 75 meters, how is it applicable to those of us who don't > > care about groundwave? > > Well, Fred, it's because it has everything to do with how much of your xmtr > power is heating the ground vs how much is being radiated at whatever frequency > you're using. We're not even talking about ground wave, it's how much power is > radiated, period. > > Walt > > Article: 214735 of rec.radio.amateur.antenna From: "Harold E. Johnson" References: <1119959789.301532.229560@z14g2000cwz.googlegroups.com> <1120252163.424289.107840@g47g2000cwa.googlegroups.com> Subject: Re: A Single-Core 4:1 Current Balun Message-ID: Date: Sat, 02 Jul 2005 01:18:05 GMT "KD5NWA" wrote in message news:1120252163.424289.107840@g47g2000cwa.googlegroups.com... > The article calls all of the devices transformers, not "conventional > transformers" including the phase inverter that is a TLT. Actually, if you'll take a read of part 2 of the application note ECO6907, (ECO7213, which I referenced) It specifically states that part 1 was devoted entirely to the design of *transmission line transformers*, which had the advantage of the widest possible bandwidth, but several disadvantages as well. Therefore, part 2 considers the possibility of applying a *conventional transformer* if those constraints were undesireable. Sheeeeeeeeesh! W4ZCB Article: 214736 of rec.radio.amateur.antenna From: "Richard Fry" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> Subject: Re: Brown, Lewis & Epstein Date: Fri, 1 Jul 2005 20:44:12 -0500 Message-ID: <42c5f1cc_4@newsfeed.slurp.net> "Walter Maxwell" > Correct on both counts, Richard, thanks for reminding Reg, I forgot to. > Did I mention that I had the privilege of working at Brown's RCA antenna > lab along side Epstein for several years? Bob Lewis had left RCA when I > arrived, but I knew him later as a ham, W2EBS. _______________ That would have been a privilege. When with RCA I worked a bit with Matti Siukola, Oded Ben-Dov, Nick Nikolayuk and others at the RCA broadcast antenna design center and test range at Gibbsboro, NJ . Great facility in those days. RF Article: 214737 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET> <4bb90$42c5e63d$97d55b49$11166@ALLTEL.NET> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Fri, 1 Jul 2005 21:46:46 -0400 "Fred W4JLE" wrote in message news:4bb90$42c5e63d$97d55b49$11166@ALLTEL.NET... > So as I understand it, as I add more radials, my field strength should > increase regardless of the elevation angle. Assuming I make all measurements > at the same point. > > > "Walter Maxwell" wrote in message > news:JEixe.22429$B_3.22179@fe05.lga... >> >> "Fred W4JLE" wrote in message >> news:4bac3$42c5b1d0$97d55b49$8639@ALLTEL.NET... >> > Walt, while this would be wonderful information if I were broadcasting >> > during the day on 75 meters, how is it applicable to those of us who > don't >> > care about groundwave? >> >> Well, Fred, it's because it has everything to do with how much of your > xmtr >> power is heating the ground vs how much is being radiated at whatever > frequency >> you're using. We're not even talking about ground wave, it's how much > power is >> radiated, period. >> >> Walt >> Fred, the radials affect only the efficiency of the radiator--power lost in the ground resistance vs power radiated. The take off, or elevation angle is determined by the ground conductivity external to the radial system, the poorer the ground the less power will radiate at low elevation angles. In other words, the better the ground conductivity external to the radial system the lower the elevation angle of the maximum radiation. If the conductivity was perfect at an infinite distance away from the radiator the elevation angle of the maximum radiation lobe would be zero degrees. Walt, W2DU Article: 214738 of rec.radio.amateur.antenna From: Jim - NN7K Subject: Re: 6 Meter Antenna References: <42C4D8E7.8E99D9B2@theforce.com> <512-42C5002D-397@storefull-3274.bay.webtv.net> <8da9d$42c5602f$97d55b49$8400@ALLTEL.NET> Message-ID: Date: Sat, 02 Jul 2005 02:03:55 GMT Might not do even that good- try to sweep the frequency with a antenna modeling program, (atleast for an analog station)! Doubt it would have the requesit 6 mHz bandwidth with this antenna!! Fred W4JLE wrote: > Bet it won't, unless your only interested in 1 channel or are in an area of > vary strong signals where it dosn't matter what you use. > > wrote in message > news:512-42C5002D-397@storefull-3274.bay.webtv.net... > >>i bet the moxon will make a good tv antenna >> > > > Article: 214739 of rec.radio.amateur.antenna From: "Chris Trask" References: Subject: Re: A Single-Core 4:1 Current Balun Message-ID: Date: Sat, 02 Jul 2005 02:05:21 GMT > > 2. That it is not a true transmission line transformer, because your > transmission-line windings are not being fed with opposite polarities > across the *same* end? > Ian, I wanted to give a more thorough reply to your question earlier, but at the time a spontaneous reply did not seem to be sufficient. So, I have put together an extensive tutorial on the subject of the theory, synthesis, and practical considerations in the design of transmission line transformers that is a result of over two decades of designing these things as a hands-on hardware designer: http://www.home.earthlink.net/~christrask/TraskTLTTutorial.pdf Chris ,----------------------. High Performance Mixers and / What's all this \ Amplifiers for RF Communications / extinct stuff, anyhow? / \ _______,--------------' Chris Trask / N7ZWY _ |/ Principal Engineer oo\ Sonoran Radio Research (__)\ _ P.O. Box 25240 \ \ .' `. Tempe, Arizona 85285-5240 \ \ / \ \ '" \ IEEE Senior Member #40274515 . ( ) \ '-| )__| :. \ Email: christrask@earthlink.net | | | | \ '. http://www.home.earthlink.net/~christrask c__; c__; '-..'>.__ Graphics by Loek Frederiks "Ian White GM3SEK" wrote in message news:wV5GouJgO7vCFAMG@ifwtech.co.uk... > Chris Trask wrote: > > > > It's not a matter of whether I disagree with him or not. It's a matter > >of him standing on a cybersoapbox and declaring to the world in numerous > >ways that such a thing cannot work and that only his analysis of how it can > >and cannot work is valid. He can't deny that he claimed that it was > >impossible, so now he has to prove that the solution cannot possibly work > >the way that he knows that it cannot work. Whatever. > > > > Please skip the personal rhetoric, and tell us how you respond to his > two main technical points about your transformer: > > 1. That it is simply a 2:1 transformer with an isolated primary and > secondary? > > 2. That it is not a true transmission line transformer, because your > transmission-line windings are not being fed with opposite polarities > across the *same* end? > > > -- > 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) > http://www.ifwtech.co.uk/g3sek Article: 214740 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: Radial Pattern For Vertical Antenna Date: Fri, 1 Jul 2005 21:16:04 -0500 Message-ID: <6043-42C5F8E4-101@storefull-3258.bay.webtv.net> References: <7Nhxe.3458$iv3.990@fe02.lga> I only wish I had contributed B, L, and E`s findings on antenna radials. My information has always come 2nd hand from its reprinting by Ed Laport in "Radio Antenna Engineering. Ed has formulas to use in choosing your ground system. I can`t find my copy of Ed`s excellent book at the moment. Laport, like Walter, W2DU, is an RCA alumnus and has associated with the famous pioneers. K6JHE did us a favor by posting the original data. Common sense says that earth closest to a vertical tower gets most of the capacitive current between the tower and the earth. It is important that density of the ground radials be high close to the tower to reduce current in the lossy soil. I think there is more to it. The area of a circle around a tower is (pi)(r)(r), where r=distance from the tower. Area grows as the square of the distance from the tower. Assume a unit depth for the earth crust, and cross-section becomes equal to the surface area. The resistance of a conductor is its resistive coefficient times its length divided by its cross-sectional area. Total resistance seen by a ground wave traveling away from a tower is an inverse function of the distance from the tower`s highly conducting ground system. The farther from the tower you get, the more cross-aection there is, so the less resistance there is in the earth. This must be in textbooks, but I don`t recall seeing it. I once asked what a-c resistance to use for the earth at 60 Hz, 50 some years ago, in a student problem and was told to use 25 ohms, no matter what the distance through earth was. That`s when I noodled out the above explanation for the earth`s resistance. It should work at r-f too except for skin effect which if I recall causes an increase in resistance proportional to the square root of the frequency. The skin thickness is proportional to the reciprocal of the square root of the frequency. The point is that high conductivity is only needed very close to the tower for the ground wave. For a sky wave, you need high conductivity at the reflection point for a vertically polarized wave. Best regards, Richard Harrison, KB5WZI Article: 214741 of rec.radio.amateur.antenna From: "Jer" References: <1120273397.616570.229180@f14g2000cwb.googlegroups.com> Subject: Re: Rotate TriBand to vertical? Message-ID: Date: Sat, 02 Jul 2005 03:32:23 GMT Why don't you just change it, its easy enough? Jer "Blue Dawg" wrote in message news:1120273397.616570.229180@f14g2000cwb.googlegroups.com... > Joh, email me at thecowboyace@yahoo.com. I hate that name but it was > what a gal did to me when she set my computer up for me on the internet > and a site deal and some other crud and I'm sorta tied into that. > Cliff G. > Article: 214742 of rec.radio.amateur.antenna From: "Frank" References: <42c43383$1_1@spool9-west.superfeed.net> <1120273060.866823.186010@g47g2000cwa.googlegroups.com> Subject: Re: Can U solve this? Message-ID: Date: Sat, 02 Jul 2005 03:47:38 GMT "Blue Dawg" wrote in message news:1120273060.866823.186010@g47g2000cwa.googlegroups.com... >I don't know exactly what you is a doin' but if you have Quatro, Excel > Spreadsheet, Lotus 123 and all of them other spreadsheet programs just > plug in the knowns and you'll get it figured out. > > That's all, Folks! Cecil, How about a clue. Can we describe the discontinuity as a two port [S] matrix? The squared magnitude of the "s" parameters does relate to power in a two port network -- am I on the right track? I took your hint, in a previous posting, and downloaded HP's 95-1. I thought I had a copy, but it seems to have evaporated. Also noted your Pfwd2 = 156.25 W, and Pref2 = 56.25 W. Is this type of reading not just a peculiarity of thru-line wattmeters. I realize you can compute mag Gamma sub p, and hence gamma sub v. Why doesn't somebody make a MathCAD NG? It would get rid of all this ugly math. Regards, Frank Article: 214743 of rec.radio.amateur.antenna From: "Frank" References: <1120274901.016516.268150@g14g2000cwa.googlegroups.com> Subject: Re: Antenna Modelling - State of the art ? Message-ID: Date: Sat, 02 Jul 2005 04:00:25 GMT wrote in message news:1120274901.016516.268150@g14g2000cwa.googlegroups.com... > Hi, > > I'd like to ask 3 questions: > > 1. Is this the main NEC users forum ? I recently tried the NEC mailing > list but is didn't seem to be operational. > > 2. Which modelling programs are considered state of the art in terms of > wire antenna modelling ? Is it NEC 4 ? > > 3. We have been using wire grids to model antennas on structures. When > I mentioned this to a non antenna modelling colleague he thought that > using a wire grid "could't be right". Now, wire grids provide a > representation of a solid surface. These types of questions can be > challenging and deserve an answer. > > So, which modelling programs are considered state of the art in terms > of modelling the infuence of structures on antenna performance ? > > Thanks, > > Michael. 1. Some people here are familiar with NEC, though most seem to use EZNEC. The NEC mailing list is at http://www.robomod.net/ 2. I would sure like to get NEC 4, but it is a bit expensive. 3. Wire grid models can adequately describe solid surfaces, providing NEC's guidelines for such models are followed. 4.As for state of the art there are at least two FEM programs available. One is HFSS from www.ansoft.com Regards, Frank Article: 214744 of rec.radio.amateur.antenna From: "Hal Rosser" References: Subject: Re: MOBILE ANTENNA MAGNETS Message-ID: <8upxe.25264$Xv.13407@bignews4.bellsouth.net> Date: Sat, 2 Jul 2005 01:21:07 -0400 Usually you can find a bunch of old cb mag-mount antennas at hamfests and at many flea markets HTH didahdah dididididah didahdahdit dadah didahdahdah "notmeman" wrote in message news:s25cc1h92766dfnkut4krgts31ici6ul92@4ax.com... > Any suggestions where I can get some strong, preferably machined for > standard screws and covered to protct paint finish, like the ones that > are one 3,4, 5 magnet mobile mounts? > > Please relpy direct to me... > > k0dan at arrl dot net > > thanks and 73 > > dan Article: 214745 of rec.radio.amateur.antenna From: Owen Subject: Re: Modeling TL "dielectric" loss Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> Date: Sat, 02 Jul 2005 05:31:02 GMT On Fri, 01 Jul 2005 20:56:25 -0700, Wes Stewart wrote: >Without wading throught the ASCII math, a couple of thoughts. I see someone else grizzling about the "ugly maths". Oh well... > >1. As Tom said, most references give the D of poly as 0.0002, >although the "Handbook of Coaxial Microwave Measurements" by General >Radio gives it as 0.0003. Ok, as I posted in another msg, my figure came from the ITT Ref Hbk, and even at 2e-4, it comes short of being the entire explanation of G derived from published loss figures. I accept that the ITT book is much lower than others. Just Googling, I see Reg's site shows 2e-5, > >2. Again, without having followed the derivation, I find the k2 >values to be different from those given by the handiwork of Dan, >AC6LA, in his XLZIZL.xls workbook or his TLdetails program. Dan used >published attenuation values and Excel regression analysis to >determine the values of k1 and k2. See: > Dans k2 figures are based on units of MHz and feet, mine are Hz and metres, and when you allow for the units base, they reconcile to within 1%. >http://www.qsl.net/ac6la/bestfit.html > >3. Also, General Radio says, "alpha(diel) does not depend at all on >the dimensions of the line..." This suggests that there should be no >difference in k2 between LDF4-50 and LDF6-50. I believe that is true, my derivation is that k2=9.09e-8 * D /vf (for units of Hz and metres). So, the "leakage" loss depends on D and 1/vf (or permittivity**0.5), and dimensions don't enter the equation. What sent me down this track is trying to reconcile this with the published specs which claim more loss than is explained by the dielectric. > Dan's numbers show that >to be the case. Dan's figure (in my ZLZIZL) is, like mine, a little lower (25%) for the larger line. It is the observation that it varies that suggests there is more to it than D alone. > >4. Any loss that doesn't follow the sqrt(f) rule (radiation, >wire-to-wire resistance of braid?, etc) as you suggest falls into the >k2 term. > >5. High-quality, high-frequency (microwave) flex cables do away with >braid, or at least solder fill it, and use tape-wound shields. Yes, see my other post regarding the LMR cables which, like the LDF series, show much less variation in k2 with cable size than moving >from RG58C/U to RG213. Thanks for the thinking Wes, Owen -- Article: 214746 of rec.radio.amateur.antenna From: "Hal Rosser" References: <42c43383$1_1@spool9-west.superfeed.net> Subject: Re: Can U solve this? Message-ID: Date: Sat, 2 Jul 2005 01:36:49 -0400 But can you solve this: A frog is in the bottom of a 10-foot well can jump 3 ft, but every time he jumps 3 ft, he slides back down 2 feet. How many clothespins does the frog need to hang up 10 towels on the clothesline, if the boat can attain a forward speed of 10 mph as he crosses a river which is running at 5 mph, and the SWR on his analyzer is 1.1 to 1 and the voltage drop across the frog's legs is 150 ohms, then what would the tax on a cup of tea cost in China when the frog gets to the top of the well. "Cecil Moore" wrote in message news:42c43383$1_1@spool9-west.superfeed.net... > It would be interesting to find out who, among the > experts on this group, cannot solve this problem > for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, > Vref2, Iref2 including magnitudes and phase > angles. > > Given: a Z0-match at an impedance discontinuity in > a transmission line. Source is unknown. Load is > unknown. Lengths of transmission lines are unknown. > Reference phase: Vfwd1 is incident upon the Z0-match > at a reference phase angle of zero degrees. > > ---50 ohm feedline---+---200 ohm feedline--- > Pfwd1=100w--> Pfwd2=156.25w--> > <--Pref1=0w <--Pref2=56.25w > > Contrary to what some people assert, is it possible > to calculate the magnitudes and phases of the > above voltages and currents knowing only the > Z0's and the forward and reflected powers? > -- > 73, Cecil, http://www.qsl.net/w5dxp > > ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- > http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups > ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 214747 of rec.radio.amateur.antenna From: "theposter" References: <8upxe.25264$Xv.13407@bignews4.bellsouth.net> Subject: Re: MOBILE ANTENNA MAGNETS Date: Fri, 1 Jul 2005 22:40:54 -0700 Message-ID: I have never seen magnets at those places. I have been too distracted by the "Magnificent Nuts" there, unless that was just a typo on your end, and that is what you were referring to. "Hal Rosser" wrote in message news:8upxe.25264$Xv.13407@bignews4.bellsouth.net... > Usually you can find a bunch of old cb mag-mount antennas at > hamfests and at > many flea markets > HTH > didahdah dididididah didahdahdit dadah didahdahdah > > "notmeman" wrote in message > news:s25cc1h92766dfnkut4krgts31ici6ul92@4ax.com... >> Any suggestions where I can get some strong, preferably machined >> for >> standard screws and covered to protct paint finish, like the ones >> that >> are one 3,4, 5 magnet mobile mounts? >> >> Please relpy direct to me... >> >> k0dan at arrl dot net >> >> thanks and 73 >> >> dan > > > Article: 214748 of rec.radio.amateur.antenna From: "theposter" References: <42c43383$1_1@spool9-west.superfeed.net> Subject: Re: Can U solve this? Date: Fri, 1 Jul 2005 23:10:51 -0700 Message-ID: <7uuc2xh118v3c2z.010720052311@kirk> sure, go ahead, toss a quantum physics word problem at us anyway it just depends on what shade of green the frog was to start with and since quantum physics teaches us that it is highly possible the frog can be in two places at once, he was already out of the well before he even began his escape, the number of clothes pins remains undetermined "Hal Rosser" wrote in message news:SIpxe.25293$Xv.15971@bignews4.bellsouth.net... > But can you solve this: > A frog is in the bottom of a 10-foot well can jump 3 ft, but every > time he > jumps 3 ft, he slides back down 2 feet. > How many clothespins does the frog need to hang up 10 towels on the > clothesline, if the boat can attain a forward speed of 10 mph as he > crosses > a river which is running at 5 mph, and the SWR on his analyzer is > 1.1 to 1 > and the voltage drop across the frog's legs is 150 ohms, then what > would the > tax on a cup of tea cost in China when the frog gets to the top of > the well. > > > "Cecil Moore" wrote in message > news:42c43383$1_1@spool9-west.superfeed.net... >> It would be interesting to find out who, among the >> experts on this group, cannot solve this problem >> for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, >> Vref2, Iref2 including magnitudes and phase >> angles. >> >> Given: a Z0-match at an impedance discontinuity in >> a transmission line. Source is unknown. Load is >> unknown. Lengths of transmission lines are unknown. >> Reference phase: Vfwd1 is incident upon the Z0-match >> at a reference phase angle of zero degrees. >> >> ---50 ohm feedline---+---200 ohm feedline--- >> Pfwd1=100w--> Pfwd2=156.25w--> >> <--Pref1=0w <--Pref2=56.25w >> >> Contrary to what some people assert, is it possible >> to calculate the magnitudes and phases of the >> above voltages and currents knowing only the >> Z0's and the forward and reflected powers? >> -- >> 73, Cecil, http://www.qsl.net/w5dxp >> >> ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure >> Usenet > News==---- >> http://www.newsfeeds.com The #1 Newsgroup Service in the World! >> 120,000+ > Newsgroups >> ----= East and West-Coast Server Farms - Total Privacy via >> Encryption > =---- > > > Article: 214749 of rec.radio.amateur.antenna From: "theposter" References: <42c43383$1_1@spool9-west.superfeed.net> Subject: Re: Can U solve this? Date: Fri, 1 Jul 2005 23:16:08 -0700 Message-ID: by the way, that chinese&tea thing, that is considered as racist as referring to blacks&watermelon you must remove that part from your word problem "Hal Rosser" wrote in message news:SIpxe.25293$Xv.15971@bignews4.bellsouth.net... > But can you solve this: > A frog is in the bottom of a 10-foot well can jump 3 ft, but every > time he > jumps 3 ft, he slides back down 2 feet. > How many clothespins does the frog need to hang up 10 towels on the > clothesline, if the boat can attain a forward speed of 10 mph as he > crosses > a river which is running at 5 mph, and the SWR on his analyzer is > 1.1 to 1 > and the voltage drop across the frog's legs is 150 ohms, then what > would the > tax on a cup of tea cost in China when the frog gets to the top of > the well. > > > "Cecil Moore" wrote in message > news:42c43383$1_1@spool9-west.superfeed.net... >> It would be interesting to find out who, among the >> experts on this group, cannot solve this problem >> for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, >> Vref2, Iref2 including magnitudes and phase >> angles. >> >> Given: a Z0-match at an impedance discontinuity in >> a transmission line. Source is unknown. Load is >> unknown. Lengths of transmission lines are unknown. >> Reference phase: Vfwd1 is incident upon the Z0-match >> at a reference phase angle of zero degrees. >> >> ---50 ohm feedline---+---200 ohm feedline--- >> Pfwd1=100w--> Pfwd2=156.25w--> >> <--Pref1=0w <--Pref2=56.25w >> >> Contrary to what some people assert, is it possible >> to calculate the magnitudes and phases of the >> above voltages and currents knowing only the >> Z0's and the forward and reflected powers? >> -- >> 73, Cecil, http://www.qsl.net/w5dxp >> >> ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure >> Usenet > News==---- >> http://www.newsfeeds.com The #1 Newsgroup Service in the World! >> 120,000+ > Newsgroups >> ----= East and West-Coast Server Farms - Total Privacy via >> Encryption > =---- > > > Article: 214750 of rec.radio.amateur.antenna From: "Hal Rosser" References: <42c43383$1_1@spool9-west.superfeed.net> Subject: Re: Can U solve this? Message-ID: Date: Sat, 2 Jul 2005 04:04:38 -0400 I think we can do this without removing that part from the problem. Add the word "cup" after every word "China", and change the word "China" to "china" in the original problem. Add the word "a" before the word "china" . Then convert every letter to its ascii equivalent and add 13 to each, then replace the characters for the new ascii values, THEN sol\ve the problem given by Cecil in the first place. I was not aware that tea was a racist word in the context of the Peoples Republic of China. Do they not tax tea any longer because of that? Does that mean its racist (or "profiling") to speak of "Sweet Tea" (Iced Tea) and Southerners in the same sentence? "theposter" wrote in message news:mtpzqhwu8mvjnab.010720052316@kirk... > by the way, that chinese&tea thing, that is considered as racist as > referring to blacks&watermelon > > you must remove that part from your word problem > > "Hal Rosser" wrote in message > news:SIpxe.25293$Xv.15971@bignews4.bellsouth.net... > > But can you solve this: > > A frog is in the bottom of a 10-foot well can jump 3 ft, but every > > time he > > jumps 3 ft, he slides back down 2 feet. > > How many clothespins does the frog need to hang up 10 towels on the > > clothesline, if the boat can attain a forward speed of 10 mph as he > > crosses > > a river which is running at 5 mph, and the SWR on his analyzer is > > 1.1 to 1 > > and the voltage drop across the frog's legs is 150 ohms, then what > > would the > > tax on a cup of tea cost in China when the frog gets to the top of > > the well. > > > > > > "Cecil Moore" wrote in message > > news:42c43383$1_1@spool9-west.superfeed.net... > >> It would be interesting to find out who, among the > >> experts on this group, cannot solve this problem > >> for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, > >> Vref2, Iref2 including magnitudes and phase > >> angles. > >> > >> Given: a Z0-match at an impedance discontinuity in > >> a transmission line. Source is unknown. Load is > >> unknown. Lengths of transmission lines are unknown. > >> Reference phase: Vfwd1 is incident upon the Z0-match > >> at a reference phase angle of zero degrees. > >> > >> ---50 ohm feedline---+---200 ohm feedline--- > >> Pfwd1=100w--> Pfwd2=156.25w--> > >> <--Pref1=0w <--Pref2=56.25w > >> > >> Contrary to what some people assert, is it possible > >> to calculate the magnitudes and phases of the > >> above voltages and currents knowing only the > >> Z0's and the forward and reflected powers? > >> -- > >> 73, Cecil, http://www.qsl.net/w5dxp > >> > >> ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure > >> Usenet > > News==---- > >> http://www.newsfeeds.com The #1 Newsgroup Service in the World! > >> 120,000+ > > Newsgroups > >> ----= East and West-Coast Server Farms - Total Privacy via > >> Encryption > > =---- > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Article: 214751 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Radial Pattern For Vertical Antenna Date: Sat, 2 Jul 2005 06:44:20 -0400 Message-ID: <11ccrvqrdeae804@corp.supernews.com> References: <7Nhxe.3458$iv3.990@fe02.lga> <6043-42C5F8E4-101@storefull-3258.bay.webtv.net> Dear Richard: Your last paragraph (quoted below) is a good summary. It, or something like it, should be an introductory paragraph in every vertical's data sheet and advertisement. Well done. To have a vertical perform well for the important (for DX) angles between 2 and 12 degrees (above the horizon) one would like to have a copper sea starting one or two wavelengths from the antenna. I have worked 10 watt backpack stations in the UK when they were by the sea side. No hope to do so when they are inland. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Richard Harrison" wrote in > > The point is that high conductivity is only needed very close to the > tower for the ground wave. For a sky wave, you need high conductivity at > the reflection point for a vertically polarized wave. > > Best regards, Richard Harrison, KB5WZI > Article: 214752 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Modeling TL "dielectric" loss Date: Sat, 2 Jul 2005 11:15:29 +0000 (UTC) Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> The fact is nobody knows the dielectric loss of polyethylene. It is too small to measure samples in a bridge. The materials of which the bridge is made have losses of the same order. The slightest unavoidable impurities and contamination during production cause wide variations in D. Coaxial line Attenuation = A*Sqrt(F) + B*F The most accurate way to estimate D at HF is to measure attenuation versus frequency over a wide frequency range on several miles of solid polyethylene coaxial line. Then separate the constants A and B by plotting on graph paper Attenuation/Sqrt(F) versus Sqrt(F). and then do a few simple calculations. I have performed this operation several times during acceptance tests on newly laid cables. The cable insulation was mainly air-spaced with the inner conductor being supported by polyethylene disks at 1.5" intervals. D can vary noticeably from one length of cable to another manufactured >from a different batch of nominally identical materials. I have also measured attenuation on many miles of 1" diameter solid polyethylene submarine cable and determined quality of the insulation by this graphical means. It is necessary to make attenuation measurements very accurately by the substitution method against standard attenuators. But for comparison, I have never measured the relative junk used by radio amateurs. ---- Reg. Article: 214753 of rec.radio.amateur.antenna Date: Sat, 02 Jul 2005 07:56:16 -0500 From: Cecil Moore Subject: Re: Can U solve this? References: <42c43383$1_1@spool9-west.superfeed.net> <1120273060.866823.186010@g47g2000cwa.googlegroups.com> Message-ID: <42c68fed$1_1@spool9-west.superfeed.net> Frank wrote: > Cecil, How about a clue. Can we describe the discontinuity as a two port > [S] matrix? The squared magnitude of the "s" parameters does relate to > power in a two port network -- am I on the right track? I took your hint, > in a previous posting, and downloaded HP's 95-1. I thought I had a copy, > but it seems to have evaporated. Also noted your Pfwd2 = 156.25 W, and > Pref2 = 56.25 W. Is this type of reading not just a peculiarity of > thru-line wattmeters. I realize you can compute mag Gamma sub p, and hence > gamma sub v. Why doesn't somebody make a MathCAD NG? It would get rid of > all this ugly math. Hi Frank, the point is that the math is not ugly. Simple math, deductive reasoning, and a four-function calculator with square root is all one needs. ---50 ohm feedline---+---200 ohm feedline--- Pfwd1=100w--> Pfwd2=156.25w--> <--Pref1=0w <--Pref2=56.25w Vfwd1 = SQRT(Pfwd1*Z01) at zero degrees = 70.7v at 0 deg Ifwd1 = SQRT(Pfwd1/Z01) at zero degrees = 1.4a at 0 deg (Vfwd1 and Ifwd1 are the reference phase angles.) Vref1 = 0 (given) Iref1 = 0 (given) Vfwd2 = SQRT(Pfwd2*Z02) at zero degrees = 176.8v at 0 deg Ifwd2 = SQRT(Pfwd2/Z02) at zero degrees = 0.88a at 0 deg Vref2 = SQRT(Pref2*Z02) at X degrees = 106v at 180 deg. Iref2 = SQRT(Pref2/Z02) at Y degrees = 0.53a at 0 deg. Note: For a Z0-match to exist: If Z02 > Z01, then X=180 degrees and Y=0 degrees If Z02 < Z01, then X=0 degrees and Y=180 degrees Vfwd2 and Vref2 have to add up to Vfwd1 Ifwd2 and Iref2 have to add up to Ifwd1 We didn't even have to calculate rho. This energy analysis works for all Z0-matched systems, the most common of amateur radio systems. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214754 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> <42c5f1cc_4@newsfeed.slurp.net> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Sat, 2 Jul 2005 09:07:37 -0400 "Richard Fry" wrote in message news:42c5f1cc_4@newsfeed.slurp.net... > "Walter Maxwell" >> Correct on both counts, Richard, thanks for reminding Reg, I forgot to. Did I >> mention that I had the privilege of working at Brown's RCA antenna lab along >> side Epstein for several years? Bob Lewis had left RCA when I arrived, but I >> knew him later as a ham, W2EBS. > _______________ > > That would have been a privilege. When with RCA I worked a bit with Matti > Siukola, Oded Ben-Dov, Nick Nikolayuk and others at the RCA broadcast antenna > design center and test range at Gibbsboro, NJ . Great facility in those days. > > RF ______________ Very interesting, Richard, of all the years I've been on this NG you are the first RCA person I've met on the NG. What years were you with RCA? While at the RCA Princeton Labs I also worked with O.M. (Woody) Woodward, Bruce Rankin, and Don Peterson. Perhaps you knew them. I joined RCA in 1949, transferred to the antenna lab in 1957, and later originated the antenna lab at the then new Astro-Electronics Division in Hightstown. Was located there until I retired to DeLand, Florida in 1980. While at Princeton I developed the entire antenna system for TIROS 1, the World's first weather satellite. I never had the pleasure of meeting any of the guys at Gibbsboro, but the names of Matti and Oded came up quite often. I heard Woody and Jess Epstein talking with them on the phone quite frequently. I also spent some time at Cherry Hill as part of a three-man team developing the 3.6 GHz dish used on Lunar Rover, the moon buggy. I performed all the final impedance and antenna pattern measurements on the three dishes prior to delivery to NASA. Perhaps we can meet some day and discuss our experiences at RCA. I consider myself fortunate to have been there during the early days of space exploration, they were truly exciting days. Walt, W2DU Article: 214755 of rec.radio.amateur.antenna Date: Sat, 02 Jul 2005 08:21:07 -0500 From: Cecil Moore Subject: Can you solve this 2? Message-ID: <42c695c0$1_2@spool9-west.superfeed.net> The first example was much too easy. How about this one? ---50 ohm feedline---+---300 ohm feedline--- Pfwd1=100w--> Pfwd2 not given--> <--Pref1=0w <--Pref2 not given Given a Z0-match at point '+': Solve for Vfwd1, Ifwd1, Vref1, Iref1, Pfwd2, Vfwd2, Ifwd2, Pref2, Vref2, Iref2, including magnitudes and phase angles for all voltages and currents. Source is unknown. Load is unknown. Lengths of feedlines are unknown. Who thinks this one is impossible to solve? -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214756 of rec.radio.amateur.antenna Date: Sat, 02 Jul 2005 08:22:29 -0500 From: Cecil Moore Subject: Re: Brown, Lewis & Epstein References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> <42c5f1cc_4@newsfeed.slurp.net> Message-ID: <42c69612$1_2@spool9-west.superfeed.net> Walter Maxwell wrote: > Very interesting, Richard, of all the years I've been on this NG you are the > first RCA person I've met on the NG. But Walt, I was once W6RCA. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214757 of rec.radio.amateur.antenna Message-ID: <313030303837383542C66C0B69@zetnet.co.uk> Date: Sat, 2 Jul 2005 10:27:23 +0100 From: Dave Piggin Subject: Re: Schematic drawings References: <1120274340.009367.249520@g44g2000cwa.googlegroups.com> > Where can one find a diluted, to a small degree, schematic drawings > related to radios/electronics? > I am on the almost side of having to watch every penny because of being > a disabled vet and having to pay a small amount of change in child > support - not griping one iota on paying child support - they be my > children but the judge sorta tapped me on the hard side. But better > days will come and better days will go and the good days always come! > Take care God Bless > Cliff > Blue Dawg > Goat Try these see if there any good to you. Dave http://www.mods.dk/view.php?ListManuals=kenwood http://www.eserviceinfo.com/index.php?what=search2 And for radio Manuals Try www.mbars.co.uk -- Amateur Radio Call Sign M1BTI, Located in Manchester England. Locator square IO83TK Chairman Of Trafford Radio Club. Club Call Signs G0TRG & M1BBP Located at Umist, University Of Manchester Institute For Science And Technology Share What You Know, Learn What You Dont. Article: 214758 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> <42c5f1cc_4@newsfeed.slurp.net> <42c69612$1_2@spool9-west.superfeed.net> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Sat, 2 Jul 2005 09:59:33 -0400 "Cecil Moore" wrote in message news:42c69612$1_2@spool9-west.superfeed.net... > Walter Maxwell wrote: >> Very interesting, Richard, of all the years I've been on this NG you are the >> first RCA person I've met on the NG. > > But Walt, I was once W6RCA. :-) > -- > 73, Cecil http://www.qsl.net/w5dxp 'ya know, Cecil, yer right, how could I have overlooked you. In fact, I've always wondered why you gave up that illustrious call sign. Walt, W2DU Article: 214759 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> <42c5f1cc_4@newsfeed.slurp.net> <42c69612$1_2@spool9-west.superfeed.net> Subject: Re: Brown, Lewis & Epstein Message-ID: Date: Sat, 2 Jul 2005 10:03:11 -0400 Since the name of Dr. George H. Brown, of Brown, Lewis and Epstein is not well known in the amateur community, I would like to acquaint you with some of his other accomplishments that are well known in the engineering community, especially in the AM-FM-TV broadcast community. His name deserves attention in the amateur community as well. In addition to his work that established the ground radial standards for AM broadcasting, he discovered the reason the early diamond-shaped tower radiators produced undesirable radiation characteristics, and proved experimentally that towers of uniform cross section solved the problem. As a result of his experimental proof, the FCC denied further use of the diamond shape tower, and has since required all AM BC antenna towers be of uniform cross section. He also developed sectionalized radiators for control of the elevation pattern. He invented the ground-plane antenna for VHF/UHF use. He found that two radials were sufficient, but marketing people convinced him that the antennas would sell better with four. With his famous 1937 paper, 'Directional Antennas' he established the basis for directional arrays used in thousands of AM broadcast stations. He worked closely with John Kraus in the early days, and showed Kraus the importance of close spacing of elements in an array to increase the gain over that obtained with quarter-wave spacing. The result was Kraus' close spaced beam known as the 'W8JK' beam. Kraus gave this credit to Brown in his book, "Antennas." He developed a method for RF heating, especially for the joining, or 'sewing' of plastic sheet material, a method that led to the development of microwave ovens. As lead engineer in RCA's color television lab at the RCA Laboratories in Princeton, he successfully led the development of the present system color system used in all US tv operations, the NTSC system that permitted black and white receivers to see color transmissions in black and white, overturning the original FCC acceptance of the CBS spinning wheel system that would not permit black and white receivers to receive color transmissions. George Brown retired as an Executive Vice President of RCA. These are just a few of his noteworthy accomplishments as an extraordinary engineer. Walt, W2DU Article: 214760 of rec.radio.amateur.antenna From: "Frank" References: <42c43383$1_1@spool9-west.superfeed.net> <1120273060.866823.186010@g47g2000cwa.googlegroups.com> <42c68fed$1_1@spool9-west.superfeed.net> Subject: Re: Can U solve this? Message-ID: Date: Sat, 02 Jul 2005 14:13:48 GMT "Cecil Moore" wrote in message news:42c68fed$1_1@spool9-west.superfeed.net... > Frank wrote: >> Cecil, How about a clue. Can we describe the discontinuity as a two port >> [S] matrix? The squared magnitude of the "s" parameters does relate to >> power in a two port network -- am I on the right track? I took your >> hint, in a previous posting, and downloaded HP's 95-1. I thought I had a >> copy, but it seems to have evaporated. Also noted your Pfwd2 = 156.25 W, >> and Pref2 = 56.25 W. Is this type of reading not just a peculiarity of >> thru-line wattmeters. I realize you can compute mag Gamma sub p, and >> hence gamma sub v. Why doesn't somebody make a MathCAD NG? It would get >> rid of all this ugly math. > > Hi Frank, the point is that the math is not ugly. Simple > math, deductive reasoning, and a four-function calculator > with square root is all one needs. > > ---50 ohm feedline---+---200 ohm feedline--- > Pfwd1=100w--> Pfwd2=156.25w--> > <--Pref1=0w <--Pref2=56.25w > > Vfwd1 = SQRT(Pfwd1*Z01) at zero degrees = 70.7v at 0 deg > Ifwd1 = SQRT(Pfwd1/Z01) at zero degrees = 1.4a at 0 deg > (Vfwd1 and Ifwd1 are the reference phase angles.) > Vref1 = 0 (given) > Iref1 = 0 (given) > > Vfwd2 = SQRT(Pfwd2*Z02) at zero degrees = 176.8v at 0 deg > Ifwd2 = SQRT(Pfwd2/Z02) at zero degrees = 0.88a at 0 deg > Vref2 = SQRT(Pref2*Z02) at X degrees = 106v at 180 deg. > Iref2 = SQRT(Pref2/Z02) at Y degrees = 0.53a at 0 deg. > > Note: For a Z0-match to exist: > If Z02 > Z01, then X=180 degrees and Y=0 degrees > If Z02 < Z01, then X=0 degrees and Y=180 degrees > Vfwd2 and Vref2 have to add up to Vfwd1 > Ifwd2 and Iref2 have to add up to Ifwd1 > > We didn't even have to calculate rho. This energy analysis > works for all Z0-matched systems, the most common of > amateur radio systems. Hi Cecil, thanks for the info, I will study your response. I did not mean that math is ugly, I meant that attempting to format in a text file is ugly. It would be so nice if what we type on was a MathCAD sheet. Regards, Frank Article: 214761 of rec.radio.amateur.antenna From: none@none.com Subject: Support for a 90 ft folded dipole - suggestions Message-ID: Date: Sat, 02 Jul 2005 14:22:51 GMT I want to raise the center of my 91 ft folded dipole to at least 35 feet. I live on the west coast of Florida with all the attendant possibilites of hurricanes. I cannot afford a retractable tower and do not have room for proper guy wires. I want to be able to put a pulley at the top so I am able to lower the antenna in the event of high winds. I have a cement block house with a roof peak of about 16 feet, I would prefer not to have to pour a base for the "mast". I would appreciate any advice on supporting the "mast" to the house wall and what material to use for the "mast" so that it might not be permanantly bent by 125 mph winds. Any constructive help gratefully welcomed Article: 214762 of rec.radio.amateur.antenna From: "theposter" References: <42c43383$1_1@spool9-west.superfeed.net> Subject: Re: Can U solve this? Date: Sat, 2 Jul 2005 08:00:24 -0700 Message-ID: absolutely correct Hal, the chinese do not consider references to themselves and tea to be racist but, the gay population in the USA does, and they are the ones calling all the shots these days the latest controversy has started when one guy in another thread came up with a word problem about two gay tea bags getting married on a chinese persons table in china, that one is not expected to blow over soon, just best to be cautious and not mention any organic matter in the same reference with a particular race or geographic population "Hal Rosser" wrote in message news:sTrxe.25551$Xv.16343@bignews4.bellsouth.net... >I think we can do this without removing that part from the problem. > Add the word "cup" after every word "China", and change the word > "China" to > "china" in the original problem. > Add the word "a" before the word "china" . Then convert every letter > to its > ascii equivalent and add 13 to each, then replace the characters for > the new > ascii values, THEN sol\ve the problem given by Cecil in the first > place. > I was not aware that tea was a racist word in the context of the > Peoples > Republic of China. > Do they not tax tea any longer because of that? > Does that mean its racist (or "profiling") to speak of "Sweet Tea" > (Iced > Tea) and Southerners in the same sentence? > > > "theposter" wrote in message > news:mtpzqhwu8mvjnab.010720052316@kirk... >> by the way, that chinese&tea thing, that is considered as racist as >> referring to blacks&watermelon >> >> you must remove that part from your word problem >> >> "Hal Rosser" wrote in message >> news:SIpxe.25293$Xv.15971@bignews4.bellsouth.net... >> > But can you solve this: >> > A frog is in the bottom of a 10-foot well can jump 3 ft, but >> > every >> > time he >> > jumps 3 ft, he slides back down 2 feet. >> > How many clothespins does the frog need to hang up 10 towels on >> > the >> > clothesline, if the boat can attain a forward speed of 10 mph as >> > he >> > crosses >> > a river which is running at 5 mph, and the SWR on his analyzer is >> > 1.1 to 1 >> > and the voltage drop across the frog's legs is 150 ohms, then >> > what >> > would the >> > tax on a cup of tea cost in China when the frog gets to the top >> > of >> > the well. >> > >> > >> > "Cecil Moore" wrote in message >> > news:42c43383$1_1@spool9-west.superfeed.net... >> >> It would be interesting to find out who, among the >> >> experts on this group, cannot solve this problem >> >> for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, >> >> Vref2, Iref2 including magnitudes and phase >> >> angles. >> >> >> >> Given: a Z0-match at an impedance discontinuity in >> >> a transmission line. Source is unknown. Load is >> >> unknown. Lengths of transmission lines are unknown. >> >> Reference phase: Vfwd1 is incident upon the Z0-match >> >> at a reference phase angle of zero degrees. >> >> >> >> ---50 ohm feedline---+---200 ohm feedline--- >> >> Pfwd1=100w--> Pfwd2=156.25w--> >> >> <--Pref1=0w <--Pref2=56.25w >> >> >> >> Contrary to what some people assert, is it possible >> >> to calculate the magnitudes and phases of the >> >> above voltages and currents knowing only the >> >> Z0's and the forward and reflected powers? >> >> -- >> >> 73, Cecil, http://www.qsl.net/w5dxp >> >> >> >> ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure >> >> Usenet >> > News==---- >> >> http://www.newsfeeds.com The #1 Newsgroup Service in the World! >> >> 120,000+ >> > Newsgroups >> >> ----= East and West-Coast Server Farms - Total Privacy via >> >> Encryption >> > =---- >> > >> > >> > >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> > > > Article: 214763 of rec.radio.amateur.antenna From: "Richard Fry" References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> <42c5f1cc_4@newsfeed.slurp.net> Subject: Re: Brown, Lewis & Epstein Date: Sat, 2 Jul 2005 08:59:31 -0500 Message-ID: <42c6af79_4@newsfeed.slurp.net> "Walter Maxwell" wrote: > Very interesting, Richard, of all the years I've been on this NG you are > the first RCA person I've met on the NG. What years were you with RCA? 1965-1980. My position certainly was not as exalted as that of Epstein/Lewis/Siukola/Maxwell/et al, but I was fortunate enough to work with Siukola and Ben-Dov of Gibbsboro in developing and proving RCA's RF Pulse test equipment system used to evaluate and optimize broadcast TV antenna systems. This test system may be thought of as a "narrow-band TDR," in that it duplicates the spectrum of the standard TV signal, rather than using a bandwidth of maybe 100X that of the TV channel. Excess test bandwidth gives high pulse returns outside the TV channel -- which are valid, but unimportant to the performance of the antenna system. RF Article: 214764 of rec.radio.amateur.antenna From: "Richard Fry" References: <11c9gbor38jn1da@corp.supernews.com> Subject: Re: Modeling TL "dielectric" loss Date: Sat, 2 Jul 2005 10:45:40 -0500 Message-ID: <42c6b704_1@newsfeed.slurp.net> "Wes Stewart"wrote: > After some fussing around, we learned that my paper Andrew catalog no. > 35 has different loss figures for the LDF series than does the "new" > online catalog no. 38. As we would say in America, like trying to > shoot at a moving target. ________________ Yes, and Andrew sometimes changes their philosophy about specs to meet certain marketing realities. I was involved in a competitive situation where my proposal for an offshore broadcast RF system included some Andrew HeliaxT. The tender spec called for a certain power rating for the coax, which by its published catalog, Andrew did not meet for the line size they proposed to us as compliant. A similar line size by an EU Andrew competitor had been bid to the end user by another tenderer, which by their spec was compliant to the tender. The customer asked for clarificatication from us/Andrew. The difference was due to Andrew's inclusion in the spec of a solar derating value for their cable, where the competitor's did not. Andrew proved their point (through us), and my proposal won. Not long after that, Andrew changed all the power ratings for their cable, removing the solar derating factor, and advising users to apply their own based on derating information they added to the catalog (similar to derating for SWR). Also note that cable attenuation and power ratings are dependent on, and stated by most OEMs only for specific ambient temperatures and a specific load SWR (1:1 in the case of Andrew). RF Article: 214765 of rec.radio.amateur.antenna From: "K9YA" Subject: FREE Subscription to Ham Radio e-Zine - K9YA Telegraph Message-ID: <3Ezxe.6769$RC6.2117@newssvr33.news.prodigy.com> Date: Sat, 02 Jul 2005 16:53:19 GMT Check out the latest issue of the K9YA Telegraph: Fishing for QSOs By Philip Cala-Lazar, K9PL My Lucky Dayton Trip By Steve Wolfcale, N9WAT Ham Radio and Scouting By Art Steinke, WB9JKY, trustee, W9BSA They Could Have and Should Have By Rod Newkirk, VA3ZBB/W9BRD Liverpool's Skyline to Flash Morse Code Messages Morse Tips & Quips Subscribe for FREE at http://www.k9ya.org Article: 214766 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: Rotate TriBand to vertical? Message-ID: References: <1120273397.616570.229180@f14g2000cwb.googlegroups.com> <1120282660.698288.202470@o13g2000cwo.googlegroups.com> Date: Sat, 02 Jul 2005 19:08:01 GMT I would rather not put a used rotor up there because of the maintenence problems. However, I will dig out the specs on the boom size and give it further thought. Thanks, John, de W8CCW On 1 Jul 2005 22:37:40 -0700, "dutchman2u" wrote: >What size is your boom . you could use a U-100 aliance rotor they have >a 1"5/8 hole throgh. You can find them on ebay for say 40-50 -or >less. Make a T on the mask pipe and mount the rotor on it side use >the clamps to the T and walla. roll it over vertial or horizonal a >very easy fix only need 3or 4 wire to make it work . also u can >insert a 15/8" in the middle of the boom .. pin it well if the boom is >2" or more .. 73 Ralph Article: 214767 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <42c43383$1_1@spool9-west.superfeed.net> <8JCxe.1898$j04.12@newssvr21.news.prodigy.com> Subject: Re: Can U solve this? Date: Sat, 2 Jul 2005 16:25:30 -0400 Message-ID: <78d25$42c6f83d$97d55b49$23718@ALLTEL.NET> Good lord, everyone knows the answer is 42... "Jim - NN7K" wrote in message news:8JCxe.1898$j04.12@newssvr21.news.prodigy.com... > 59.43 Parsecs per millinea is the answer! (unless you want to convert it > into Furlongs per Fortnights )! NN7K > > theposter wrote: > > by the way, that chinese&tea thing, that is considered as racist as > > referring to blacks&watermelon > > > > you must remove that part from your word problem > > > > "Hal Rosser" wrote in message > > news:SIpxe.25293$Xv.15971@bignews4.bellsouth.net... > > > >>But can you solve this: > >>A frog is in the bottom of a 10-foot well can jump 3 ft, but every > >>time he > >>jumps 3 ft, he slides back down 2 feet. > >>How many clothespins does the frog need to hang up 10 towels on the > >>clothesline, if the boat can attain a forward speed of 10 mph as he > >>crosses > >>a river which is running at 5 mph, and the SWR on his analyzer is > >>1.1 to 1 > >>and the voltage drop across the frog's legs is 150 ohms, then what > >>would the > >>tax on a cup of tea cost in China when the frog gets to the top of > >>the well. > >> > >> > >>"Cecil Moore" wrote in message > >>news:42c43383$1_1@spool9-west.superfeed.net... > >> > >>>It would be interesting to find out who, among the > >>>experts on this group, cannot solve this problem > >>>for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, > >>>Vref2, Iref2 including magnitudes and phase > >>>angles. > >>> > >>>Given: a Z0-match at an impedance discontinuity in > >>>a transmission line. Source is unknown. Load is > >>>unknown. Lengths of transmission lines are unknown. > >>>Reference phase: Vfwd1 is incident upon the Z0-match > >>>at a reference phase angle of zero degrees. > >>> > >>>---50 ohm feedline---+---200 ohm feedline--- > >>> Pfwd1=100w--> Pfwd2=156.25w--> > >>> <--Pref1=0w <--Pref2=56.25w > >>> > >>>Contrary to what some people assert, is it possible > >>>to calculate the magnitudes and phases of the > >>>above voltages and currents knowing only the > >>>Z0's and the forward and reflected powers? > >>>-- > >>>73, Cecil, http://www.qsl.net/w5dxp > >>> > >>>----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure > >>>Usenet > >> > >>News==---- > >> > >>>http://www.newsfeeds.com The #1 Newsgroup Service in the World! > >>>120,000+ > >> > >>Newsgroups > >> > >>>----= East and West-Coast Server Farms - Total Privacy via > >>>Encryption > >> > >>=---- > >> > >> > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Article: 214768 of rec.radio.amateur.antenna From: "Hal Rosser" References: <8upxe.25264$Xv.13407@bignews4.bellsouth.net> Subject: Re: MOBILE ANTENNA MAGNETS Message-ID: Date: Sat, 2 Jul 2005 16:28:04 -0400 I may have generalized too much. Since I found old mag-mount cb antennas at flea markets and hamfests I assumed anyone could do the same. They were not sold as "magnets" - they were sold as old mag-mount cb antennas. The magnets just happened to be at the bottom of the antennas. I suppose different flea markets have different offerings at different times. I should not generalize. I should have given you a story of how I had found magnets, and infer that similar actions may have similar results. My apologies. "theposter" wrote in message news:tdbv4i5bibvqlfw.010720052241@kirk... > I have never seen magnets at those places. I have been too distracted > by the "Magnificent Nuts" there, unless that was just a typo on your > end, and that is what you were referring to. Article: 214769 of rec.radio.amateur.antenna From: "Hal Rosser" References: Subject: Re: Support for a 90 ft folded dipole - suggestions Message-ID: Date: Sat, 2 Jul 2005 16:45:17 -0400 be careful attaching it to the house. The amount of overhang will affect that task. Take a look at the power company's service entrances to most homes. Most will penetrate the roof and come down a wall. Some use "unistrut" and "unistrut straps" to mount pipe to a wall - available at an Electrical Supply house like Graybar. If you use 2" heavywall galvanized conduit - and fill it with concrete, it will resist bending pretty good. Mount a pulley on the top to raise the antenna. If you try to attach the pipe to just a facia board, remember that the facia board *could* come loose. wrote in message news:q58dc1hnec9cvkg4htcotpb99n0v2gglt8@4ax.com... > I want to raise the center of my 91 ft folded dipole to at least 35 > feet. I live on the west coast of Florida with all the attendant > possibilites of hurricanes. I cannot afford a retractable tower and do > not have room for proper guy wires. I want to be able to put a pulley > at the top so I am able to lower the antenna in the event of high > winds. I have a cement block house with a roof peak of about 16 feet, > I would prefer not to have to pour a base for the "mast". > I would appreciate any advice on supporting the "mast" to the house > wall and what material to use for the "mast" so that it might not be > permanantly bent by 125 mph winds. > > Any constructive help gratefully welcomed > Article: 214770 of rec.radio.amateur.antenna From: "theposter" References: <8upxe.25264$Xv.13407@bignews4.bellsouth.net> Subject: Re: MOBILE ANTENNA MAGNETS Date: Sat, 2 Jul 2005 14:13:16 -0700 Message-ID: hal you pegged me, i do frequent those places, the bargains are too good to pass up you can pickup very powerful magnets on ebay though, a guy may wish to check that out "Hal Rosser" wrote in message news:qMCxe.21664$qm.437@bignews5.bellsouth.net... > > I may have generalized too much. Since I found old mag-mount cb > antennas at > flea markets and hamfests I assumed anyone could do the same. They > were not > sold as "magnets" - they were sold as old mag-mount cb antennas. The > magnets > just happened to be at the bottom of the antennas. > I suppose different flea markets have different offerings at > different > times. > I should not generalize. I should have given you a story of how I > had found > magnets, and infer that similar actions may have similar results. > My apologies. > > > "theposter" wrote in message > news:tdbv4i5bibvqlfw.010720052241@kirk... >> I have never seen magnets at those places. I have been too >> distracted >> by the "Magnificent Nuts" there, unless that was just a typo on >> your >> end, and that is what you were referring to. > > > Article: 214771 of rec.radio.amateur.antenna From: Howard Subject: Re: Support for a 90 ft folded dipole - suggestions Date: Sat, 02 Jul 2005 14:23:22 -0700 Message-ID: References: On Sat, 2 Jul 2005 16:45:17 -0400, "Hal Rosser" wrote: >be careful attaching it to the house. The amount of overhang will affect >that task. >Take a look at the power company's service entrances to most homes. Most >will penetrate the roof and come down a wall. Some use "unistrut" and >"unistrut straps" to mount pipe to a wall - available at an Electrical >Supply house like Graybar. If you use 2" heavywall galvanized conduit - and >fill it with concrete, it will resist bending pretty good. Mount a pulley on >the top to raise the antenna. > If you try to attach the pipe to just a facia board, remember that the >facia board *could* come loose. > Hal, I don't have an immediate need to put up a mast but like your idea with the unistrut! Hope I remember it when I need it. Howard Article: 214772 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Support for a 90 ft folded dipole - suggestions Message-ID: <1c1ec1lteinlroknug2egsva8sj7p6omdo@4ax.com> References: <1120315173.111624.311850@g43g2000cwa.googlegroups.com> Date: Sat, 02 Jul 2005 21:29:23 GMT On Sat, 2 Jul 2005 12:15:35 -0700, "Chuck Olson" wrote: > > wrote in message >news:1120315173.111624.311850@g43g2000cwa.googlegroups.com... >> A rat shack pushup pole, *properly* guyed, should do the >> trick. I'm not sure about 125 mph winds though. I'm not >> sure many would survive that...But... The pushup masts >> are retractable. What I do when a hurricane is coming, >> is to retract the mast down to it lowest level. That makes >> it super strong, and being low, there is little risk. I've >> had those masts ride out hurricanes, even all the way up. >> But...It wasn't 125 mph though... Maybe 100-105 mph or so... >> You can buy the brackets for the house. >> MK >> > >Yes, Radio Shack used to carry them, but not any more, unless you just >happen to find one in a store left over from when they had them. Someone >said Lowes had them, but the stores in the S.F. Bay Area don't - - and in an >on-line search of their stock they don't recognize the product, so maybe >that's dated information, too. I suspect with cable and satellite, hardly >anybody goes to the trouble of putting up an outside TV antenna any more, so >from disuse, we may have lost that resource. There still might be masts >available through small town TV installers in the fringe area around big >cities, but I don't see anything on line except for Wholesale Electronics >Inc who have no stock on hand. The latest manufacturer to take over some of >the business from Rohn, Nello Corp. says they will have a line of >telescoping masts in the Fall of 2005, so you might be able to get one then >through Array Solutions on the West coast or AN Wireless in the East.. > >If anyone reading this has a 30 ft 3-section TV mast they're willing to sell >for a reasonable price, I'd be interested myself. > >73, Chuck W6PKP > Hmm, Radio Shack used to carry telescoping masts; no more though, according to their web site. However, Lowe's Home Improvement does list a guyed 30-foot telescoping mast. Probably special order. Oh, well... bob k5qwg From news.my180.net Sat Jul 9 09:14:37 EDT 2005 Article: 214773 of rec.radio.amateur.antenna From: "denton" Newsgroups: rec.radio.amateur.antenna Subject: Re: Support for a 90 ft folded dipole - suggestions Date: Sat, 2 Jul 2005 15:13:09 -0700 Organization: Posted via Supernews, http://www.supernews.com Message-ID: <11ce4biofjggg74@corp.supernews.com> References: X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-RFC2646: Format=Flowed; Original X-Complaints-To: abuse@supernews.com Lines: 23 Path: news1.isis.unc.edu!canoe.uoregon.edu!hammer.uoregon.edu!news.glorb.com!sn-xit-04!sn-xit-06!sn-post-02!sn-post-01!supernews.com!corp.supernews.com!not-for-mail Xref: news1.isis.unc.edu rec.radio.amateur.antenna:214773 See if a farm supply house or welding shop has some of those square steel tubing...they usually come in 22 ft lengths. You can then get one that will telescope in a slightly larger one. A pier pad at the bottom should be enough to support the bottom and they are very stout, but still can be raised by one person, and you might find that kind of mast won't require guying. wrote in message news:q58dc1hnec9cvkg4htcotpb99n0v2gglt8@4ax.com... >I want to raise the center of my 91 ft folded dipole to at least 35 > feet. I live on the west coast of Florida with all the attendant > possibilites of hurricanes. I cannot afford a retractable tower and do > not have room for proper guy wires. I want to be able to put a pulley > at the top so I am able to lower the antenna in the event of high > winds. I have a cement block house with a roof peak of about 16 feet, > I would prefer not to have to pour a base for the "mast". > I would appreciate any advice on supporting the "mast" to the house > wall and what material to use for the "mast" so that it might not be > permanantly bent by 125 mph winds. > > Any constructive help gratefully welcomed > Article: 214774 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 08:21:11 +1000 From: atec Subject: Re: Support for a 90 ft folded dipole - suggestions References: Message-ID: <42c712fb$1@dnews.tpgi.com.au> none@none.com wrote: > I want to raise the center of my 91 ft folded dipole to at least 35 > feet. I live on the west coast of Florida with all the attendant > possibilites of hurricanes. I cannot afford a retractable tower and do > not have room for proper guy wires. I want to be able to put a pulley > at the top so I am able to lower the antenna in the event of high > winds. I have a cement block house with a roof peak of about 16 feet, > I would prefer not to have to pour a base for the "mast". > I would appreciate any advice on supporting the "mast" to the house > wall and what material to use for the "mast" so that it might not be > permanantly bent by 125 mph winds. > > Any constructive help gratefully welcomed > If you can find a competent machinist in your area then purchase two decent size pipes and have the machinist install a base seal so you can force mains pressure into the base , the centre pipe will lift and then can be locked at full height or dropped in moments.. hope you follow what I mean .Ten metres is very achievable for little outlay , a simple short guy and bracket to the house will strong if installed correctly , talk to a carpenter for good advice .Good luck. Article: 214775 of rec.radio.amateur.antenna From: "Edward A. Feustel" References: <1120315173.111624.311850@g43g2000cwa.googlegroups.com> Subject: Re: Support for a 90 ft folded dipole - suggestions Date: Sat, 2 Jul 2005 11:12:38 -0400 Message-ID: <42c7153d$1_1@spool9-west.superfeed.net> wrote in message news:1120315173.111624.311850@g43g2000cwa.googlegroups.com... >A rat shack pushup pole, *properly* guyed, should do the > trick. I'm not sure about 125 mph winds though. I'm not > sure many would survive that...But... The pushup masts > are retractable. What I do when a hurricane is coming, > is to retract the mast down to it lowest level. That makes > it super strong, and being low, there is little risk. I've > had those masts ride out hurricanes, even all the way up. > But...It wasn't 125 mph though... Maybe 100-105 mph or so... > You can buy the brackets for the house. > MK > > It is not clear that Radio Shack sells the pushup masts anymore. I got the last one at our store. Rohn made them and they went bankrupt. You might use Google to search the web for pushup antenna masts. I used to use a wooden mast to support my folded dipole. it was based on a mast in the ARRL Handbook or Antenna book. It consisted of an 8 foot treated 2 by 4 planted in the ground. This was "double carriage bolted" to a pair of 20 foot pair of 2 by 4 which was double carriage bolded to a single 20 foot 2 by 4. At least 3 feet overlap between sections is desired. I did not find it necessary to have a guy. I attached the center of the folded dipole to a hook at the top of the now 35 foot mast. The only problem I see is the cross section of the 2 by 4 in 125 mile per hour winds. If the lower 20 feet were up against the house, you might not have a problem. Otherwise guys will be essential. Probably 3 at the top of the pair of 2 by 4s and two (one to either flat side) of the top piece. Make certain that you get strong lumber, preferably not pine. Regards, Ed, N5EI ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 214776 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <1120333949.135501.228840@z14g2000cwz.googlegroups.com> Subject: Re: reflectivity of wire mesh (wire screen) Message-ID: Date: Sat, 2 Jul 2005 18:27:22 -0400 "Wimpie" wrote in message news:1120333949.135501.228840@z14g2000cwz.googlegroups.com... > Hello, > > Wire mesh or parallel bars are often used as a replacement for solid > reflectors. > > Is there any practical formula, computer program or graph for > calculating the (plane wave) reflectivity/reflection coefficient of > wire mesh (for example chicken mesh)? > > I am thinking of a formula where you have to enter cell/grid size, wire > thickness and frequency. > > With kind regards, > > Wim Telkamp If the cell dimension of the grid is 1/20 wl the grid is considered to be effective as a continuous reflective plane. The same dimension of spacing between parallel wires is also effective as a continuous reflector for EM waves whose polarization is parallel with the wires. Walt, W2DU Article: 214777 of rec.radio.amateur.antenna From: Owen Subject: Re: Modeling TL "dielectric" loss Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> Date: Sat, 02 Jul 2005 22:28:01 GMT On Sat, 02 Jul 2005 07:54:12 -0700, Wes Stewart wrote: >On Sat, 02 Jul 2005 05:31:02 GMT, Owen wrote: > > >0.0002 is from the ITT Handbook, fourth and fifth editions. Rechecking my sixth edition, it is 2e-4 at 100MHz, I need new glasses for these books with tiny print. Thanks... Owen -- Article: 214778 of rec.radio.amateur.antenna From: Owen Subject: Re: Modeling TL "dielectric" loss Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> Date: Sat, 02 Jul 2005 23:23:35 GMT On Sat, 2 Jul 2005 11:15:29 +0000 (UTC), "Reg Edwards" wrote: ... Noted. >The most accurate way to estimate D at HF is to measure attenuation >versus frequency over a wide frequency range on several miles of solid >polyethylene coaxial line. > >Then separate the constants A and B by plotting on graph paper >Attenuation/Sqrt(F) versus Sqrt(F). and then do a few simple >calculations. Ok, as I stated earlier, I am working from published specs rather than my own measurements, and I understand there are issues about the reliability of published specs. I didn't plot the values on graph paper to find A and B (or k1 and k2), but used a least squares regression to find A and B (and r**2, the correlation coefficient as an indicator of the quality of the fit). What I was trying to do was to develop an RLGC model for the line from published figures (attenuation at spot frequencies, nominal Ro, vf), and I can do that. The issue about the dielectric came up in trying to reconcile the G / D / k2 figures with the knowledge that the cable had PE dielectric and should have had D=2e-4 (I stand corrected on my misreading of the value 2e-5 from my ITT Handbook by Wes - thanks). The purpose of the model and validation are for my online transmission line loss calculator. The notes to the calculator show the modelled loss vs the data points in one of the graphs at http://www.vk1od.net/tl/tllc.php . >D can vary noticeably from one length of cable to another manufactured >from a different batch of nominally identical materials. > Ok, noted. I have added a few words to the explanatory notes on the calculator. Thanks for the help all. Owen -- Article: 214779 of rec.radio.amateur.antenna Date: Sat, 02 Jul 2005 19:41:35 -0500 From: Cecil Moore Subject: Re: Brown, Lewis & Epstein References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> <1120178173.488687.160210@f14g2000cwb.googlegroups.com> <42c5c04a_4@newsfeed.slurp.net> <42c5f1cc_4@newsfeed.slurp.net> <42c69612$1_2@spool9-west.superfeed.net> Message-ID: <42c7353d$1_2@spool9-west.superfeed.net> Walter Maxwell wrote: > 'ya know, Cecil, yer right, how could I have overlooked you. In fact, I've > always wondered why you gave up that illustrious call sign. A land of fruits and nuts call didn't fit very well in Texas, :-) just kidding. I was first licensed as WN5DXP in 1952 and just couldn't resist getting my old call back when I moved back to the same land as I lived on then, land homesteaded by my grandfather before the 20th century. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214780 of rec.radio.amateur.antenna From: Bob McConnell Subject: Re: reflectivity of wire mesh (wire screen) Message-ID: References: <1120333949.135501.228840@z14g2000cwz.googlegroups.com> Date: Sun, 03 Jul 2005 03:15:53 GMT On Sat, 2 Jul 2005 18:27:22 -0400, "Walter Maxwell" wrote: > >"Wimpie" wrote in message >news:1120333949.135501.228840@z14g2000cwz.googlegroups.com... >> Hello, >> >> Wire mesh or parallel bars are often used as a replacement for solid >> reflectors. >> >> Is there any practical formula, computer program or graph for >> calculating the (plane wave) reflectivity/reflection coefficient of >> wire mesh (for example chicken mesh)? >> >> I am thinking of a formula where you have to enter cell/grid size, wire >> thickness and frequency. >> >> With kind regards, >> >> Wim Telkamp > >If the cell dimension of the grid is 1/20 wl the grid is considered to be >effective as a continuous reflective plane. The same dimension of spacing >between parallel wires is also effective as a continuous reflector for EM waves >whose polarization is parallel with the wires. > >Walt, W2DU > I believe that when the openings in the grid are half of the wavelength, half the signal ( -3 dB) gets through and half is reflected. As the gaps get smaller, more signal is reflected. I've never seen a formula for it. Bob McConnell N2SPP Article: 214781 of rec.radio.amateur.antenna From: "Hal Rosser" References: <42c695c0$1_2@spool9-west.superfeed.net> Subject: Re: Can you solve this 2? Message-ID: Date: Sun, 3 Jul 2005 00:23:37 -0400 Just hook it up and see if it works. If not, change one the "thingys" and try again. Repeat until it works. end loop "Cecil Moore" wrote in message news:42c695c0$1_2@spool9-west.superfeed.net... > The first example was much too easy. How about this one? > > ---50 ohm feedline---+---300 ohm feedline--- > Pfwd1=100w--> Pfwd2 not given--> > <--Pref1=0w <--Pref2 not given > > Given a Z0-match at point '+': > Solve for Vfwd1, Ifwd1, Vref1, Iref1, Pfwd2, Vfwd2, Ifwd2, > Pref2, Vref2, Iref2, including magnitudes and phase angles > for all voltages and currents. Source is unknown. Load is > unknown. Lengths of feedlines are unknown. > > Who thinks this one is impossible to solve? > -- > 73, Cecil http://www.qsl.net/w5dxp > > > ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- > http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups > ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214782 of rec.radio.amateur.antenna From: "John Smith" References: <42c695c0$1_2@spool9-west.superfeed.net> Subject: Re: Can you solve this 2? Message-ID: Date: Sat, 2 Jul 2005 21:26:17 -0700 Hal: Could you explain that in less technical terms? John "Hal Rosser" wrote in message news:gKJxe.25351$qm.5904@bignews5.bellsouth.net... > Just hook it up and see if it works. > If not, change one the "thingys" and try again. > Repeat until it works. > end loop > > > "Cecil Moore" wrote in message > news:42c695c0$1_2@spool9-west.superfeed.net... >> The first example was much too easy. How about this one? >> >> ---50 ohm feedline---+---300 ohm feedline--- >> Pfwd1=100w--> Pfwd2 not given--> >> <--Pref1=0w <--Pref2 not given >> >> Given a Z0-match at point '+': >> Solve for Vfwd1, Ifwd1, Vref1, Iref1, Pfwd2, Vfwd2, Ifwd2, >> Pref2, Vref2, Iref2, including magnitudes and phase angles >> for all voltages and currents. Source is unknown. Load is >> unknown. Lengths of feedlines are unknown. >> >> Who thinks this one is impossible to solve? >> -- >> 73, Cecil http://www.qsl.net/w5dxp >> >> >> ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure >> Usenet > News==---- >> http://www.newsfeeds.com The #1 Newsgroup Service in the World! >> >100,000 > Newsgroups >> ---= East/West-Coast Server Farms - Total Privacy via Encryption >> =--- > > Article: 214783 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Radial Pattern For Vertical Antenna Date: Sun, 3 Jul 2005 01:05:21 -0400 Message-ID: <11cesg3kgpbe56b@corp.supernews.com> References: <7Nhxe.3458$iv3.990@fe02.lga> <6043-42C5F8E4-101@storefull-3258.bay.webtv.net> <11ccrvqrdeae804@corp.supernews.com> <1120314795.523639.121290@g49g2000cwa.googlegroups.com> Dear Mark: I had to look up your location in order to put your story into context. You are in Texas. Thanks for the story. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net wrote in message news:1120314795.523639.121290@g49g2000cwa.googlegroups.com... > I have worked 10 watt > backpack stations in the UK when they were by the sea side. No hope to > do > so when they are inland. > > > Three or four weeks ago I drove down to the beach to do > some fishing, bbqing, and general r&r. Of course, I had my > radio. I pulled my truck right up next to the water. Didn't > bother throwing a "water" ground wire out. Just ran normal > with my "extended" 14 ft mobile whip. The coil 8 ft above the > base of the whip. 100w. Was yakking on 40m late at night, and among > all the stations, mostly home stations, some running power, > I was one of the loudest ones on the freq. Can't beat a good > saltwater location. :) Also, a mobile late at night on 40m, > generally is as good as most normal height dipoles, etc. In fact, > I had one guy do a test. He was in the house in FLA, and I wagered > that his signal would increase if he went to his mobile. > He did, and it did. MK > Article: 214784 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Modeling TL "dielectric" loss Date: Sun, 3 Jul 2005 06:26:57 +0000 (UTC) Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> Owen, Are you aware of programs - RJELINE2, RJELINE3, for balanced pair lines, and COAXPAIR, COAXRATE for coaxial lines ? These are based on exact, classical transmission line formulae and will tell you all you could wish to know about behaviour of transmission lines versus any complex termination from open circuit to short circuit. No approximation of critical parameters. However, in the coaxial case, dielectric loss is an input quantity. ;o) ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 214785 of rec.radio.amateur.antenna From: Owen Subject: Re: Modeling TL "dielectric" loss Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> Date: Sun, 03 Jul 2005 07:16:42 GMT On Sun, 3 Jul 2005 06:26:57 +0000 (UTC), "Reg Edwards" wrote: >Owen, > >Are you aware of programs - Yes, of course, Reg, they and the rest of the suite are interesting... In validating my calcualator, I have compared it to yours, Dan's XLZIZL / TLD, Dean's TLA and Kevin's java applet. They all produce slightly different results, one of the reasons I have tried to document the assumptions that underly my calculator. > >RJELINE2, RJELINE3, for balanced pair lines, > >and COAXPAIR, COAXRATE for coaxial lines ? > >These are based on exact, classical transmission line formulae and >will tell you all you could wish to know about behaviour of >transmission lines versus any complex termination from open circuit to >short circuit. No approximation of critical parameters. > >However, in the coaxial case, dielectric loss is an input quantity. >;o) Yes, I played with a model of Belden 8262, it is pasted below, and will probably be line wrapped by a lot of news readers. I have plugged in the dimensions from the 8262 spec sheet, and it produces some results that are inconsistent with the specs. The insulant diameter from the spec sheet is 4.5mm, loss/Km 13dB. (The value for O was chosen to calibrate the DC loop resistance.) At 1GHZ, the calculated loss was 35dB against spec of 21dB. I played with it for a while trying to calibrate against the B8262 specs, but was unsuccessful. Owen N. Nominal Zo, ohms . 50.0 TERMINATION/LOAD ------------- ohms --- D. Inner diameter, mm 0.889 R. Series Resistance 0.0 O. Outer thickness mm 0.080 X. Series Reactance 50.0 V. Velocity Factor Vf 0.6600 EQUIVALENT TERMINATION ------- ohms --- T. Loss Factor ...... 0.000200 S. Shunt Resistance 2500000000.0 L. Line Length metres 100.000 Y. Shunt Reactance 50.0 F. Freq, kilo-Hertz . 1000.00 ----------------------------- LINE CHARACTERISTICS --------------------------- Insulant diameter 3.14 millimetres. Total Attn 10.5898 dB/kilo-m Magnitude of Zo 51.79 ohms. Dielectric Loss 0.0275 dB/kilo-m Angle of Zo -2.112 degrees. RF Resistance 0.1258 ohms/metre Relative Velocity 0.6373 Inductance 0.2705 uH/metre Electrical length 0.523 wavelengths. Capacitance 101.1476 pF/metre DC Loop resistance 49.063 ohms/kilo-m. Conductance 0.1271 uS/metre ----------------------------- INPUT IMPEDANCE Zin ---------------------------- Series Resistance 16.51 ohms. Equivalent Shunt R 271.28 ohms Series Reactance 64.86 ohms. Equivalent Shunt X 69.07 ohms Magnitude of Zin 66.93 ohms. Angle of Zin 75.716 degrees -------------------------- TRANSMISSION PERFORMANCE -------------------------- Reflection coeff. 1.0375 Line loss when matched 1.0590 dB Refl.coeff. angle 92.01 degrees. Actual line loss 70.8624 dB VSWR at termination 54.296 Actual power loss in line 100.000 percent VSWR at line input 9.696 Skin Depth 0.066 mm Q 13.5 Length = Q(1/4-wave) A(dd 1/4-wave) 3(dB) 6(0dB) =(.2%) -(.2%) Hit N,D,O,V,T,L,F,R,X,S,Y to change data. B(egin again), E(xit program) -- Article: 214786 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Modeling TL "dielectric" loss Date: Sun, 03 Jul 2005 01:33:42 -0700 Message-ID: <11cf8n9cu87h933@corp.supernews.com> References: <11c9gbor38jn1da@corp.supernews.com> If you want to work from published specs, you should find this interesting, from the Belden catalog: It looks like 8214 and 9913F7 are the same except that 9913F7 has a solid aluminum shield between the insulation and the braided copper shield. 9913F7 claims lower loss, amounting to 0.9 dB at 400 MHz. One might conclude that the difference is due to the extra shield, presumably because it's smooth and not braided. It looks like 9914 is the same as 9913F7 except that 9914 has a solid rather than stranded center conductor. The spec for 9914 shows less loss, amounting to 0.4 dB less at 400 MHz. One might conclude that the difference is due to stranded vs. solid center conductor. I think your analysis isn't valid for two reasons. The first is that you're relying on published specifications. (For example, I just measured the Z0 of ten "50 ohm" cables of different brands and types I have on hand -- it ranged from 44.6 to 56.8 ohms. I already reported a loss measurement that was quite different from the spec.) The second is that your model is overly simplified. It looks like you're trying to account for all the loss mechanisms in a coax cable by considering only the dielectric and conductor losses in idealized materials, or at best two factors which are proportional to F and proportional to the square root of F. In order to get a decent fit, I think you'll have to include additional factors for such things as the effect of stranding the center conductor and the extra loss associated with a braided shield, which might well be different functions of frequency. Of course, tinned conductors, which are very common, will alter the loss characteristics depending on the composition of the plating, and change the shape of the loss vs. frequency curve at a frequency depending on the depth of the plating. Once you start really digging, I think you'll find other mechanisms, such as perhaps how tight a woven shield is -- it wouldn't take much of an air gap between the shield and the insulation to have some pretty noticeable effects. I went through this excercise of attempting to predict coax cable loss many years ago (my notes say 1991) and abandoned the effort as being too time consuming. I hope you'll be willing to devote the time and effort necessary to come up with a reasonably accurate model. Roy Lewallen, W7EL Article: 214787 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Modeling TL "dielectric" loss Date: Sun, 3 Jul 2005 11:20:01 +0000 (UTC) Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> <11cf8n9cu87h933@corp.supernews.com> Roy said - > I think your analysis isn't valid for two reasons. The first is that > you're relying on published specifications. (For example, I just > measured the Z0 of ten "50 ohm" cables of different brands and types I > have on hand -- it ranged from 44.6 to 56.8 ohms. I already reported a > loss measurement that was quite different from the spec.) ======================================== The greatest source of divergence between manufacturers' specifications and what you think you've actually got is due to manufacturing variation in cable dimensions. Such as : Inner coaxial wire diameter as it is drawn through diamond dies. Ovality of wire drawn through worn dies. Tightness of stranded inner conductors affecting diameter. Diameter over the extruded polyethylene insulant. Affected by temperature. Off-centre eccentricity of inner conductor within the insulant. Ovality of the polyethylene extrusion. Diameter of braiding wires. Tightness of braid over polyethylene. Longitudinal tension in braid. Tightness of copper or aluminium tapes over polyethylene. Tightness of PVC jacket or other protection over braid or tapes. - and a dozen other dimensional factors which I have long forgotten. There's also variation in the conductivity of annealed copper wire and contaminants in polyethylene due to lack of cleanliness in storage. During manufacture, as the product is drawn through machinery, electrical characteristics change. They can become cyclic. When measuring long lengths small reflections can accumulate causing attenuation versus frequency curves to exhibit a slow ripple about the average slope of A*Sqrt(F)+B*F dB. ( The most unreliable manufacturer's specification I have seen, associated with attenuation and power rating, allowed cable to be used at a temperature of the melting point of polyethylene. Would burn the skin off your hands. Testing equipment???? ) Important factors are the inevitable errors in all measuring instruments, especially so-called SWR meters, and the delusions of accuracy usually suffered by everybody involved. It's so easy to draw the wrong conclusions! ---- Reg, G4FGQ Article: 214788 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Brown, Lewis & Epstein Message-ID: References: <67p7c1ppcdm5piv42018h3qekfbt7bp339@4ax.com> Date: Sun, 03 Jul 2005 12:59:00 GMT On Thu, 30 Jun 2005 05:32:33 -0700, Dan Richardson arrlnet> wrote: > >Therefore, I have placed on my web site a scanned copy of "Ground >Systems As A Factor In Antenna Efficiency" by G.H. Brown, R.F. Lewis >and J. Epstein which was publish by Institute of Radio Engineers in >June 1937. This scanned copy is identical in format as a copy I >obtained from the library. I downloaded your PDF file and burned it to a disk. Very interesting paper -- I can even understand much of it (I ain't no engineer) -- Intrigued by the picture of the "plow" they used to lay miles and miles of radials -- wish I had one. bob k5qwg > >Be advised that you need Adobe Reader for viewing. Additionally, this >is a rather large file (about 3MB). > >You may view this document at: > >http://users.adelphia.net/~k6mhe/BLE.html > >73, >Danny, K6MHE Article: 214789 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 08:04:20 -0500 From: Cecil Moore Subject: Re: Tram Penetrator dipole and other things References: <1120357889.380362.40300@g49g2000cwa.googlegroups.com> Message-ID: <42c7e352$1_2@spool9-west.superfeed.net> Blue Dawg wrote: > Where in the same hill will I be able to put the Penetrator at? My GMC pickup has three trailer hitch holes. My screwdriver is mounted in one of them. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214790 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 08:23:34 -0500 From: Cecil Moore Subject: Re: Can you solve this 2? References: <42c695c0$1_2@spool9-west.superfeed.net> Message-ID: <42c7e7d4$1_2@spool9-west.superfeed.net> Cecil Moore wrote: > The first example was much too easy. How about this one? > > ---50 ohm feedline---+---300 ohm feedline--- > Pfwd1=100w--> Pfwd2 not given--> > <--Pref1=0w <--Pref2 not given > > Given a Z0-match at point '+': > Solve for Vfwd1, Ifwd1, Vref1, Iref1, Pfwd2, Vfwd2, Ifwd2, > Pref2, Vref2, Iref2, including magnitudes and phase angles > for all voltages and currents. Source is unknown. Load is > unknown. Lengths of feedlines are unknown. > > Who thinks this one is impossible to solve? I just received an email from someone who solved it. Now who says an energy analysis is impossible or meaningless? -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214791 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: Rotate TriBand to vertical? Message-ID: References: <4eodc19qrjp629jgjgaah8rtn66an6uatn@4ax.com> Date: Sun, 03 Jul 2005 13:25:40 GMT That would work. The problem that it is pricy (Yaesu-$320), heavy (8 pounds), may not be enough to handle an HF tribander. On Sat, 02 Jul 2005 14:49:56 -0400, Buck wrote: >Install an elevation rotor. > >On Fri, 01 Jul 2005 19:26:56 GMT, John Ferrell > wrote: > >>I have a Cushcraft A3 beam on a crank up/tilt over tower. When I tilt >>it over, it still requires a ladder to work on it due to the length of >>the elements. >> >>What I would like to do is to be able to rotate it as though I were >>trying for vertical polarization before or during the tilt over >>process. That would bring the antenna to a "flat" attitude for >>maintenance and storm protection. >> >>Any thoughts? The usual old fashioned Ham parameters apply: Little >>cost as possible, build as much as I can my self, etc...... >> >>BTW, I have several good TV rotators I might use, but none with a hole >>all the way through! >> >>de W8CCW Article: 214792 of rec.radio.amateur.antenna From: Buck Subject: Re: Rotate TriBand to vertical? Date: Sun, 03 Jul 2005 09:43:53 -0400 Message-ID: References: <4eodc19qrjp629jgjgaah8rtn66an6uatn@4ax.com> On Sun, 03 Jul 2005 13:25:40 GMT, John Ferrell wrote: >That would work. The problem that it is pricy (Yaesu-$320), heavy (8 >pounds), may not be enough to handle an HF tribander. > >On Sat, 02 Jul 2005 14:49:56 -0400, Buck wrote: > >>Install an elevation rotor. >> I had an Alliance Tenna Rotor for years. It worked well and only cost $50 used. The only other alternative might be to create yourself a bracket that you can loosen. Lower the antenna part way, Loosen the bracket and turn the antenna by hand. Then finish lowering the tower. The only other alternative I see that you haven't rejected is to mount the beam vertical and leave it that way when you raise the tower. Good luck N4PGW -- 73 for now Buck N4PGW Article: 214793 of rec.radio.amateur.antenna From: "Dennis Gibbs" Subject: Evaluating location for radio activities Message-ID: Date: Sun, 3 Jul 2005 10:55:29 -0400 Hello all, I am beginning the process of searching for some land on which to build a home. It will be located in the Pacific Northwest, in a fairly rural area. I expect to indulge myself heavily in my radio hobbies, including ham radio (especially on the HF bands) as well as a fair amount of Short Wave Listening. I would like to solicit advice on how to evaluate a potential location for quality of radio reception. Aside from the obvious (i.e., a high elevation, away from high voltage power lines, plenty of room for antennas, etc.), are there any other attributes I should consider to ensure the location will be conducive to my radio activities? Dennis R390A@Cox.net Article: 214794 of rec.radio.amateur.antenna From: W9DMK (Robert Lay) Subject: Re: Can you solve this 2? Date: Sun, 03 Jul 2005 15:05:32 GMT Message-ID: <42c7f8f6.3567850@news.crosslink.net> References: <42c695c0$1_2@spool9-west.superfeed.net> On Sat, 02 Jul 2005 08:21:07 -0500, Cecil Moore wrote: >The first example was much too easy. How about this one? > >---50 ohm feedline---+---300 ohm feedline--- > Pfwd1=100w--> Pfwd2 not given--> > <--Pref1=0w <--Pref2 not given > >Given a Z0-match at point '+': >Solve for Vfwd1, Ifwd1, Vref1, Iref1, Pfwd2, Vfwd2, Ifwd2, >Pref2, Vref2, Iref2, including magnitudes and phase angles >for all voltages and currents. Source is unknown. Load is >unknown. Lengths of feedlines are unknown. Without disclosing the answers or the exact procedure for solving the "brain teaser", I would like to draw attention to some of the implicit relationships that "ought" to help. 1) It is assumed that both feelines have purely resistive characteristic impedances (imaginary component, Xo, is zero). 2) Regardless of the length of the 300 ohm line and its termination impedance, the standing wave pattern and the voltages and currents, both incident and reflected as a function of distance x along that line are determined completely by the requirement/condition that there is a Z0 match at point "+". 3) There are an infinite number of lengths of the 300 ohm line and a corresponding infinite number of termination impedances for that line that will produce a Z0 match at point "+". However, because of (2), above, some of those combinations are well known combinations with well understood results (e.g., odd multiple of quarter wavelength or an integer number of half wavelengths). 4) Due to conditions (1) and (2) above, the phase relations between all of the voltages and currents immediately adjacent to either side of point "+" are trivial (i.e., any two quantities chosen will be either exactly in phase or exactly 180 degrees out of phase with one another). Due to (3) and (4) above, it would seem that an arbitrary choice of either a quarter wave line with an 1800 ohm termination or a half wave line with a 50 ohm termination would provide a convenient example with which to begin an analysis. However, that is not necessary and only provides a crutch to get off dead center. If all of the above elements are kept in mind, then it becomes a matter of solving a simple algebraic relationship involving 4 equations with 4 unknowns (the incident and reflected voltages and currents at the right hand side of point "+"). The actual numerical answer to such a problem is irrelevant. The points to be learned from all this are really the implicit relationships (2), (3) and (4) above. Without an understanding of those points, it is virtually impossible to even know where to start. I think that is the real point that Cecil is trying to make. Bob, W9DMK, Dahlgren, VA Replace "nobody" with my callsign for e-mail http://www.qsl.net/w9dmk http://zaffora/f2o.org/W9DMK/W9dmk.html Article: 214795 of rec.radio.amateur.antenna From: David Subject: Re: Evaluating location for radio activities Message-ID: References: Date: Sun, 03 Jul 2005 15:11:18 GMT On Sun, 3 Jul 2005 10:55:29 -0400, "Dennis Gibbs" wrote: > >Hello all, > >I am beginning the process of searching for some land on which to build a >home. It will be located in the Pacific Northwest, in a fairly rural area. >I expect to indulge myself heavily in my radio hobbies, including ham radio >(especially on the HF bands) as well as a fair amount of Short Wave >Listening. I would like to solicit advice on how to evaluate a potential >location for quality of radio reception. > >Aside from the obvious (i.e., a high elevation, away from high voltage power >lines, plenty of room for antennas, etc.), are there any other attributes I >should consider to ensure the location will be conducive to my radio >activities? > >Dennis >R390A@Cox.net > > Why just ''high voltage'' power lines? I'd avoid all power lines. Article: 214796 of rec.radio.amateur.antenna From: "John Plimmer" Subject: Re: Evaluating location for radio activities Date: Sun, 3 Jul 2005 17:21:29 +0200 Message-ID: References: Yes, the single most important location for outstanding DX on LF, MW and HF is to site yourself right on the beach. Much discussion has taken place about the "ideal" DX site and there is considerable consensus among serious DXer's that DXing on the waters edge at the beachside gives a major boost to signals. Good luck in finding the Holy Grail of DX sites -- John Plimmer, Montagu, Western Cape Province, South Africa South 33 d 47 m 32 s, East 20 d 07 m 32 s Icom IC-756 PRO III with MW mods RX Drake R8B, SW8 & ERGO software Sony 7600D GE SRIII BW XCR 30, Braun T1000, Sangean 818 & 803A. Hallicrafters SX-100, Eddystone 940 GE circa 50's radiogram Antenna's RF Systems DX 1 Pro, Datong AD-270 Kiwa MW Loop http://www.dxing.info/about/dxers/plimmer.dx "Dennis Gibbs" wrote in message news:I%Sxe.52790$R21.3417@lakeread06... > Hello all, > > I am beginning the process of searching for some land on which to build a > home. It will be located in the Pacific Northwest, in a fairly rural area. > I expect to indulge myself heavily in my radio hobbies, including ham radio > (especially on the HF bands) as well as a fair amount of Short Wave > Listening. I would like to solicit advice on how to evaluate a potential > location for quality of radio reception. > > Aside from the obvious (i.e., a high elevation, away from high voltage power > lines, plenty of room for antennas, etc.), are there any other attributes I > should consider to ensure the location will be conducive to my radio > activities? > > Dennis > R390A@Cox.net > > Article: 214797 of rec.radio.amateur.antenna From: David Subject: Re: Evaluating location for radio activities Message-ID: References: Date: Sun, 03 Jul 2005 16:10:07 GMT On Sun, 3 Jul 2005 17:21:29 +0200, "John Plimmer" wrote: > >Yes, the single most important location for outstanding DX on LF, MW and HF >is to site yourself right on the beach. >Much discussion has taken place about the "ideal" DX site and there is >considerable consensus among serious DXer's that DXing on the waters edge at >the beachside gives a major boost to signals. > >Good luck in finding the Holy Grail of DX sites Pacific Northwest is Tsunami Country. All the good cliffs are taken. Article: 214798 of rec.radio.amateur.antenna From: "Pat Whelton" Subject: Feed Line Length - Ladder Line Message-ID: <3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net> Date: Sun, 03 Jul 2005 17:50:55 GMT I've had a store bought (so sue me) dipole fed with 600 ohm ladder line up 35 feet for about a year and a half now and I love this antenna. It's 66 feet in length and I can pretty much tune everything from 40 through 10 meters with a Dentron Super Tuner. This thing came with 50 feet of ladder line and I have it draped all over the place trying to take up the slack before it finally feeds into the shack. My question is can I safely cut some of this excess ladder line off? I assume that it will impact the tuning but I'm also assuming the tuner will take care of it. I guess I can always cut it off and if it doesn't work I can wire nut it back together again. It just looks sloppy with all this extra feed line drooping off the roof and suspended by the fence (and over to grandma's house we go) before it finally comes into the shack. Your thoughts are appreciated. Article: 214799 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 13:43:12 -0500 From: Cecil Moore Subject: Re: Can you solve this 2? References: <42c695c0$1_2@spool9-west.superfeed.net> <42c7f8f6.3567850@news.crosslink.net> Message-ID: <42c832be$1_2@spool9-west.superfeed.net> W9DMK (Robert Lay) wrote: > The actual numerical answer to such a problem is irrelevant. The > points to be learned from all this are really the implicit > relationships (2), (3) and (4) above. Without an understanding of > those points, it is virtually impossible to even know where to start. > I think that is the real point that Cecil is trying to make. Actually, it is one mm broader than that. In the above analysis, an energy analysis works just as well as any other, contrary to the Sacred Cow Lamentations I and II of some experts on this newsgroup. There is so much redundancy built into the voltage, current, and power relationships in a transmission line that there are a number of valid ways to skin the cat. An energy analysis is one of those valid ways. Two people have sent me emails with correct solutions. Here's how to approach the solution from an energy standpoint. ---50 ohm feedline---+---300 ohm feedline--- Pfwd1=100w--> Pfwd2 not given--> <--Pref1=0w <--Pref2 not given rho=250/350=0.7143, rho^2 = 0.51, (1-rho^2) = 0.49 rho^2 is the power reflection coefficient. (1-rho^2) is the power transmission coefficient. Pfwd1*rho^2 = 100*0.51 = 51w reflected back toward the source at the match point. My article labels that quantity 'P3' Pfwd1*(1-rho^2) = 100*0.49 = 49 watts transmitted through the match point toward the load. My article labels that quantity 'P1' (as does Dr. Best's QEX article). For a match to exist Pref2(1-rho^2) must equal 51w, the part of Pref2 transmitted back through the match point, i.e. not re-reflected. My article labels that quantity 'P4' That makes Pref2 = 51w/0.49 = 104.1w, and makes Pref2(rho^2) = 53.1w, the part initially re-reflected. My article labels that quantity 'P2' as does Dr. Best's QEX article. So Pfwd2 = P1 + P2 + P3 + P4 = 49w + 53.1w + 51w + 51w = 204.1w Who said powers can never be added? Pfwd2 is indeed 204.1w. Now that we know all the powers (without knowing a single voltage) we can calculate the voltages and currents whose phase angles are all either zero degrees or 180 degrees. As Bob sez, phase angles are trivial at a Z0-match point. Is there anybody out there who still believes that an energy analysis is impossible and/or "gobbledegook"? Incidentally, the two 51w component powers represent the amount of destructive interference energy involved in wave cancellation and the amount of constructive interference energy re-reflected toward the load as a result of that wave cancellation. This is something that Dr. Best completely missed in his QEX article. He correctly identified P1 and P2 but completely ignored P3 and P4. Thus he came up with the equation: Ptot = 75w + 8.33w = 133.33w. Remember that argument on this newsgroup from spring of 2001? -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214800 of rec.radio.amateur.antenna From: "Hal Rosser" References: <42c695c0$1_2@spool9-west.superfeed.net> Subject: Re: Can you solve this 2? Message-ID: Date: Sun, 3 Jul 2005 14:43:38 -0400 I would have used the term "Whatchacallit", but "thingy" seems to work. "John Smith" wrote in message news:JNJxe.23942$b_3.21074043@news.sisna.com... > Hal: > > Could you explain that in less technical terms? > > John > > "Hal Rosser" wrote in message > news:gKJxe.25351$qm.5904@bignews5.bellsouth.net... > > Just hook it up and see if it works. > > If not, change one the "thingys" and try again. > > Repeat until it works. > > end loop > > > > > > "Cecil Moore" wrote in message > > news:42c695c0$1_2@spool9-west.superfeed.net... > >> The first example was much too easy. How about this one? > >> > >> ---50 ohm feedline---+---300 ohm feedline--- > >> Pfwd1=100w--> Pfwd2 not given--> > >> <--Pref1=0w <--Pref2 not given > >> > >> Given a Z0-match at point '+': > >> Solve for Vfwd1, Ifwd1, Vref1, Iref1, Pfwd2, Vfwd2, Ifwd2, > >> Pref2, Vref2, Iref2, including magnitudes and phase angles > >> for all voltages and currents. Source is unknown. Load is > >> unknown. Lengths of feedlines are unknown. > >> > >> Who thinks this one is impossible to solve? > >> -- > >> 73, Cecil http://www.qsl.net/w5dxp > >> > >> > >> ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure > >> Usenet > > News==---- > >> http://www.newsfeeds.com The #1 Newsgroup Service in the World! > >> >100,000 > > Newsgroups > >> ---= East/West-Coast Server Farms - Total Privacy via Encryption > >> =--- > > > > > > Article: 214801 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 13:44:06 -0500 From: Cecil Moore Subject: Re: Evaluating location for radio activities References: Message-ID: <42c832f4$1_2@spool9-west.superfeed.net> David wrote: > Why just ''high voltage'' power lines? I'd avoid all power lines. Hard to do inside a house with power lines. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214802 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 13:48:38 -0500 From: Cecil Moore Subject: Re: Feed Line Length - Ladder Line References: <3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net> Message-ID: <42c83404$1_2@spool9-west.superfeed.net> Pat Whelton wrote: > My question is can I safely cut some of this excess ladder line off? I > assume that it will impact the tuning but I'm also assuming the tuner will > take care of it. May be a rash assumption. Trimming the feedline will change the impedance the tuner sees and the tuner may (or may not) like the new impedances. How about downloading the free demo version of EZNEC from www.eznec.com and seeing for yourself what the tuner will see? -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214803 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: Rotate TriBand to vertical? Message-ID: <0jfgc1p7q6ilue7ll1mv3og6ih0gc4ejbd@4ax.com> References: <4eodc19qrjp629jgjgaah8rtn66an6uatn@4ax.com> Date: Sun, 03 Jul 2005 19:41:01 GMT Thanks for the ideas. It takes a taller ladder than I like to loosen the boom mount bolts. I may eventually work it out. Or, may be I will live with what I have. John, de W8CCW On Sun, 03 Jul 2005 09:43:53 -0400, Buck wrote: >On Sun, 03 Jul 2005 13:25:40 GMT, John Ferrell > wrote: > >>That would work. The problem that it is pricy (Yaesu-$320), heavy (8 >>pounds), may not be enough to handle an HF tribander. >> >>On Sat, 02 Jul 2005 14:49:56 -0400, Buck wrote: >> >>>Install an elevation rotor. >>> > > >I had an Alliance Tenna Rotor for years. It worked well and only cost >$50 used. > >The only other alternative might be to create yourself a bracket that >you can loosen. Lower the antenna part way, Loosen the bracket and >turn the antenna by hand. Then finish lowering the tower. > >The only other alternative I see that you haven't rejected is to mount >the beam vertical and leave it that way when you raise the tower. > >Good luck >N4PGW Article: 214804 of rec.radio.amateur.antenna From: "Joe S." Subject: Re: Evaluating location for radio activities Date: Sun, 3 Jul 2005 15:42:39 -0500 Message-ID: References: "Dennis Gibbs" wrote in message news:I%Sxe.52790$R21.3417@lakeread06... > Hello all, > > I am beginning the process of searching for some land on which to build a > home. It will be located in the Pacific Northwest, in a fairly rural area. > I expect to indulge myself heavily in my radio hobbies, including ham radio > (especially on the HF bands) as well as a fair amount of Short Wave > Listening. I would like to solicit advice on how to evaluate a potential > location for quality of radio reception. > > Aside from the obvious (i.e., a high elevation, away from high voltage power > lines, plenty of room for antennas, etc.), are there any other attributes I > should consider to ensure the location will be conducive to my radio > activities? > > Dennis > R390A@Cox.net > > You need to drop by the local building codes office. Your home site will be located in a county or inside a city or town limit. Rules vary from place to place but every place has building codes and inspectors who inspect construction to ensure the codes are enforced. Code enforcement varies from place to place -- I built houses in West Virginia, southwest Virginia, northeast Tennessee, and southeast Kentucky -- there were some counties where we never saw an inspector and the guy who issued our building permit at the county courthouse could not even read blueprint house plans -- but in other counties they inspected us at every turn. If you are building in the county -- outside city or town limits -- the county will inspect you. If you are building inside a city or town limit, their inspectors will inspect your construction or they may use the county inspectors, or, your construction may be inspected by both county and town/city. You need to check with the inspector's office or whichever office issues building permits to see if they enforce codes on towers and antennas. You may find that you can put up any tower, any height, anywhere you want -- or -- you may find that putting up even the simplest antenna support will require engineering drawings, environmental impact statement, and several inspections. Remember, too, if you are in the flight path of an airport, even a local grass strip, you will have height limits and lighting requirements on towers. Also, you are likely to be wiring your house for a ham station, which means one room or one corner of the house will have several 110VAC outlets plus one or more 220VAC outlets for linear(s). The electrical inspector will find this strange and you need to talk with him BEFORE you even think about building so you get him on board with you -- he will tell you what the codes require so you don't have to rip out any wiring. Don't forget, too, that you will need some way for cables to go out of the house to the antennas -- and anytime you poke a hole in a wall, the inspectors get nosy -- you will need to ensure that the cable egress location has proper sealing, fire blocking, insulation, etc. Also, you'll need to ground the station -- talk to the inspector about that because he may look askance at a #4 copper wire running to a ground rod in addition to the one required at the entrance panel. Remember, too, when you start laying out your floor plan -- if you have water (a sink) within a few feet of the ham station, the outlets may be required to be GFCI protected -- and you don't want GFCI on your ham station outlets because you will forever be tripping the GFCI and shutting off the power -- so locate the ham station away from sinks and faucets. Bottom line: Find your local building codes office and get to know them LONG before you select a building site. -- ----- Joe S. Article: 214805 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net> Subject: Re: Feed Line Length - Ladder Line Date: Sun, 3 Jul 2005 17:08:46 -0400 Message-ID: 50 foot is a neat length in that if you plot all the impedances at the various bands you fill find a current max fairly close to 50 feet. Cutting the length may move you closer to a match on some frequencies and further away, and beyond the range of your tuner on others. I am not familiar with the specs of your tuner so can not be more definitive. All this being said, cut it, if your tuner matches it your golden. If not reattach the cut section. Take a look at Cecil's site, he has an antenna that he tunes via feedline length. He has a number of graphs and a smith chart that will answer your questions. http://www.qsl.net/w5dxp/notuner.htm "Pat Whelton" wrote in message news:3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net... > I've had a store bought (so sue me) dipole fed with 600 ohm ladder line up > 35 feet for about a year and a half now and I love this antenna. It's 66 > feet in length and I can pretty much tune everything from 40 through 10 > meters with a Dentron Super Tuner. This thing came with 50 feet of ladder > line and I have it draped all over the place trying to take up the slack > before it finally feeds into the shack. > > My question is can I safely cut some of this excess ladder line off? I > assume that it will impact the tuning but I'm also assuming the tuner will > take care of it. I guess I can always cut it off and if it doesn't work I > can wire nut it back together again. It just looks sloppy with all this > extra feed line drooping off the roof and suspended by the fence (and over > to grandma's house we go) before it finally comes into the shack. > > Your thoughts are appreciated. > > Article: 214806 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net> Subject: Re: Feed Line Length - Ladder Line Message-ID: Date: Sun, 3 Jul 2005 18:34:03 -0400 Pat, the correct length for a feedline is that which reaches from the feed point of the antenna to the terminals of the tuner. Having used the Dentron Supertuner I doubt if you'll have any trouble matching any impedance you'll find at the input of the feed line. If it doesn't match on any particular band there are four ways to achieve the match, depending on the specific impedance at the input of the line. Try a series cap in the line, or try a parallel cap across the line, or do the same thing with an inductor to see which works. It's cut and try, but it's better than having the line coiled up in the bathtub. Walt, W2DU Article: 214807 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Can you solve this 2? References: <42c695c0$1_2@spool9-west.superfeed.net> <42c7f8f6.3567850@news.crosslink.net> Message-ID: Date: Sun, 03 Jul 2005 22:48:51 GMT W9DMK (Robert Lay) wrote: > On Sat, 02 Jul 2005 08:21:07 -0500, Cecil Moore > wrote: > > >>The first example was much too easy. How about this one? >> >>---50 ohm feedline---+---300 ohm feedline--- >> Pfwd1=100w--> Pfwd2 not given--> >> <--Pref1=0w <--Pref2 not given >> >>Given a Z0-match at point '+': >>Solve for Vfwd1, Ifwd1, Vref1, Iref1, Pfwd2, Vfwd2, Ifwd2, >>Pref2, Vref2, Iref2, including magnitudes and phase angles >>for all voltages and currents. Source is unknown. Load is >>unknown. Lengths of feedlines are unknown. > > > Without disclosing the answers or the exact procedure for solving the > "brain teaser", I would like to draw attention to some of the implicit > relationships that "ought" to help. > 1) It is assumed that both feelines have purely resistive > characteristic impedances (imaginary component, Xo, is zero). > 2) Regardless of the length of the 300 ohm line and its termination > impedance, the standing wave pattern and the voltages and currents, > both incident and reflected as a function of distance x along that > line are determined completely by the requirement/condition that there > is a Z0 match at point "+". > 3) There are an infinite number of lengths of the 300 ohm line and a > corresponding infinite number of termination impedances for that line > that will produce a Z0 match at point "+". However, because of (2), > above, some of those combinations are well known combinations with > well understood results (e.g., odd multiple of quarter wavelength or > an integer number of half wavelengths). > 4) Due to conditions (1) and (2) above, the phase relations between > all of the voltages and currents immediately adjacent to either side > of point "+" are trivial (i.e., any two quantities chosen will be > either exactly in phase or exactly 180 degrees out of phase with one > another). > > Due to (3) and (4) above, it would seem that an arbitrary choice of > either a quarter wave line with an 1800 ohm termination or a half wave > line with a 50 ohm termination would provide a convenient example with > which to begin an analysis. However, that is not necessary and only > provides a crutch to get off dead center. > > If all of the above elements are kept in mind, then it becomes a > matter of solving a simple algebraic relationship involving 4 > equations with 4 unknowns (the incident and reflected voltages and > currents at the right hand side of point "+"). > > The actual numerical answer to such a problem is irrelevant. The > points to be learned from all this are really the implicit > relationships (2), (3) and (4) above. Without an understanding of > those points, it is virtually impossible to even know where to start. > I think that is the real point that Cecil is trying to make. > > Bob, W9DMK, Dahlgren, VA > Replace "nobody" with my callsign for e-mail > http://www.qsl.net/w9dmk > http://zaffora/f2o.org/W9DMK/W9dmk.html > Cecil already defined the voltage and current at the match point when he gave the characteristic impedances of the two lines and the rate of energy transfer through them. Knowing the voltage and current, anyone can calculate Pfwd2 and Prev2 using Pfwd2 = |(V+IZ0)/2sqrt(Z0)|^2 and Prev = |(V-IZ0)/2sqrt(Z0)|^2, where Z0 is the characteristic impedance of the second transmission line. Cecil's ability to add powers together, which he did in this instance, isn't anything unique, and doesn't really teach anything about the general case. In fact, for a quarter wave transformer, you can do the following trick: compute the value of the power as it just comes through the impedance discontinuity for the first time and call it Pa. Call Rho^2 at the load P. Then the power delivered to the load will be Pa( 1 + P + P^2 + P^3 + P^4 ....) which looks the same as if the power reflection coefficient looking back toward the generator was 1 and the power at the load was the result of the addition of an infinite number of reflections. Such an interpretation, though, can be shown to be absolutely wrong. Can anyone see why? 73, Tom Donaly, KA6RUH Article: 214808 of rec.radio.amateur.antenna From: Owen Subject: Re: Modeling TL "dielectric" loss Message-ID: References: <11c9gbor38jn1da@corp.supernews.com> <11cf8n9cu87h933@corp.supernews.com> Date: Sun, 03 Jul 2005 22:53:11 GMT On Sun, 3 Jul 2005 11:20:01 +0000 (UTC), "Reg Edwards" wrote: >Roy said - >> I think your analysis isn't valid for two reasons. The first is that >> you're relying on published specifications. (For example, I just >> measured the Z0 of ten "50 ohm" cables of different brands and types >I >> have on hand -- it ranged from 44.6 to 56.8 ohms. I already reported >a >> loss measurement that was quite different from the spec.) > >======================================== > >The greatest source of divergence between manufacturers' >specifications and what you think you've actually got is due to >manufacturing variation in cable dimensions. > Thanks Roy and Reg, I understand your point that the calculation engine is more precise than the model accuracy (against specs), and the product manufacturing tolerances introduce an even larger error in the predictions. Not mentioned, but installation and through life degradation introduces yet another uncertain and possibly greater issue. Appreciate all the input. I am sure you are right Roy, this could go on indefinitely. I think I have gone far enough for the purpose, probably too far, but that is the cost of confidence that I have gone far enough! Thanks again. Owen -- Article: 214809 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 18:37:34 -0500 From: Cecil Moore Subject: Re: Antenna Tuner for 20m Dipole - Build References: <42c5265f@news.iconz.co.nz> <42c53602$1_1@spool9-west.superfeed.net> <4nZxe.12578$jX6.11054@newsread2.news.pas.earthlink.net> Message-ID: <42c877bc$1_2@spool9-west.superfeed.net> Old Ed wrote: > And you suggest he deliberately create a 5:1 or so SWR at the antenna > by using a mismatched feedline, just so he can have the joy of building > and using a tuned feeder??? Sheesh! Horses for courses, Cecil. I'm not familiar with the TS-830 so I assumed he had a real problem. It's a sub-set of the same problem I solved with my 20m rotatable dipole. I provided the same solution I presently use and with it he gets the added bonus of 20m-10m operation. BTW, 13 cent/ft 450 ohm ladder-line with a 9:1 SWR is a lot less lossy than 13 cent/ft coax with an SWR of 1:1. He gets all band operation above 14 MHz and greater efficiency for half the price. Why is that over the top? :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214810 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 19:17:58 -0500 From: Cecil Moore Subject: Re: Can you solve this 2? References: <42c695c0$1_2@spool9-west.superfeed.net> <42c7f8f6.3567850@news.crosslink.net> Message-ID: <42c88135$1_1@spool9-west.superfeed.net> Tom Donaly wrote: > Cecil's ability to add powers together, which he did in > this instance, isn't anything unique, and doesn't > really teach anything about the general case. I'm glad you agree, Tom. Other experts on this newsgroup will argue with you as they have with me for four years ever since Dr. Best posted his infamous Z0-match equation: Ptot = 75w + 8.33w = 133.33w to which I objected back then, only to have most of the rest of the posters agree with Dr. Best. I was dumbfounded to see so many otherwise knowledgable engineers agree to a violation of the principle of conservation of energy. I was told not to worry about conservation of energy - that it takes care of itself. > In fact, for a quarter wave transformer, you can > do the following trick: compute the value of the > power as it just comes through the impedance discontinuity > for the first time and call it Pa. Call Rho^2 at the > load P. Then the power delivered to the load will be > Pa( 1 + P + P^2 + P^3 + P^4 ....) which looks the > same as if the power reflection coefficient looking > back toward the generator was 1 and the power at the > load was the result of the addition of an infinite > number of reflections. Such an interpretation, though, > can be shown to be absolutely wrong. Can anyone see why? Destructive interference between the external reflection at the match point and the internal reflection from the load supplies additional constructive interference energy to the forward wave in the quarter wave transformer. You didn't include that constructive interference energy above. Hint: That virtual power reflection coefficient looking rearward into the match point doesn't reach 1 until steady- state is reached (wrong premise above). The virtual power reflection coefficient looking forward into the match point also doesn't reach 0 until steady-state is reached. Those two virtual power reflection coefficients actually start out the same value and proceed in opposite directions during the transient buildup to steady-state. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214811 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 19:25:09 -0500 From: Cecil Moore Subject: Re: Antenna Tuner for 20m Dipole - Build References: <42c5265f@news.iconz.co.nz> <42c53602$1_1@spool9-west.superfeed.net> <4nZxe.12578$jX6.11054@newsread2.news.pas.earthlink.net> Message-ID: <42c882e3$1_1@spool9-west.superfeed.net> Dan Richardson wrote: > wrote: >>I know you like to tout ladder-line/tuned feeder as the solution for >>everything from SHF to ingrown toenails... > > My thoughts exactly, but more eloquently stated. I had no idea what a TS-830 was. I was just trying to be helpful. And that's exactly the solution I use with my SGC-500. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214812 of rec.radio.amateur.antenna From: "Tom Donaly" Subject: Re: Can you solve this 2? References: <42c695c0$1_2@spool9-west.superfeed.net> <42c7f8f6.3567850@news.crosslink.net> <42c88135$1_1@spool9-west.superfeed.net> Message-ID: <8R%xe.217$Tc6.201@newssvr13.news.prodigy.com> Date: Mon, 04 Jul 2005 00:58:44 GMT Cecil Moore wrote: > Tom Donaly wrote: > >> Cecil's ability to add powers together, which he did in >> this instance, isn't anything unique, and doesn't >> really teach anything about the general case. > > > I'm glad you agree, Tom. Other experts on this newsgroup > will argue with you as they have with me for four years > ever since Dr. Best posted his infamous Z0-match equation: > > Ptot = 75w + 8.33w = 133.33w > > to which I objected back then, only to have most of > the rest of the posters agree with Dr. Best. I was > dumbfounded to see so many otherwise knowledgable > engineers agree to a violation of the principle of > conservation of energy. I was told not to worry about > conservation of energy - that it takes care of itself. > >> In fact, for a quarter wave transformer, you can >> do the following trick: compute the value of the >> power as it just comes through the impedance discontinuity >> for the first time and call it Pa. Call Rho^2 at the >> load P. Then the power delivered to the load will be >> Pa( 1 + P + P^2 + P^3 + P^4 ....) which looks the >> same as if the power reflection coefficient looking >> back toward the generator was 1 and the power at the >> load was the result of the addition of an infinite >> number of reflections. Such an interpretation, though, >> can be shown to be absolutely wrong. Can anyone see why? > > > Destructive interference between the external reflection > at the match point and the internal reflection from the > load supplies additional constructive interference > energy to the forward wave in the quarter wave transformer. > You didn't include that constructive interference energy > above. Hint: That virtual power reflection coefficient looking > rearward into the match point doesn't reach 1 until steady- > state is reached (wrong premise above). The virtual power > reflection coefficient looking forward into the match point > also doesn't reach 0 until steady-state is reached. Those > two virtual power reflection coefficients actually start out > the same value and proceed in opposite directions during > the transient buildup to steady-state. Hi Cecil, you come up with the right answer, but is your interpretation correct? Can you do the same thing in a general sense? If there is no Z0 match between the two transmission lines, does your method still work? The little conundrum I posed is an example of a procedure that will actually give the right answer, but the interpretation I gave of how it works is wrong. Can you be sure your method doesn't have the same flaw? 73, Tom Donaly, KA6RUH (P.S. The method of using V and I and the junction of the two xmission lines to find the forward and reverse powers on a transmission line doesn't prove the powers exist. It works just as easily with a pair of resistors and is more an algebraic stunt that works than anything else. It does agree with you, however.) Article: 214813 of rec.radio.amateur.antenna From: N7ZZT - Eric Oyen Subject: Re: Can U solve this? References: <42c43383$1_1@spool9-west.superfeed.net> Message-ID: Date: Sun, 03 Jul 2005 20:47:24 -0700 This is solvable, you just need to figure out which unknown term to solve for first. Cecil Moore wrote: > It would be interesting to find out who, among the > experts on this group, cannot solve this problem > for Vfwd1, Ifwd1, Vref1, Iref1, Vfwd2, Ifwd2, > Vref2, Iref2 including magnitudes and phase > angles. > > Given: a Z0-match at an impedance discontinuity in > a transmission line. Source is unknown. Load is > unknown. Lengths of transmission lines are unknown. > Reference phase: Vfwd1 is incident upon the Z0-match > at a reference phase angle of zero degrees. > > ---50 ohm feedline---+---200 ohm feedline--- > Pfwd1=100w--> Pfwd2=156.25w--> > <--Pref1=0w <--Pref2=56.25w > > Contrary to what some people assert, is it possible > to calculate the magnitudes and phases of the > above voltages and currents knowing only the > Z0's and the forward and reflected powers? -- DE N7ZZT Eric Oyen Phoenix, Arizona e-mail: n7zzt(at)hotmail(dot)com the difference between intelligence and stupidity is that intelligence has its limits. Article: 214814 of rec.radio.amateur.antenna From: "Old Ed" References: <42c5265f@news.iconz.co.nz> <42c53602$1_1@spool9-west.superfeed.net> <4nZxe.12578$jX6.11054@newsread2.news.pas.earthlink.net> <42c877bc$1_2@spool9-west.superfeed.net> Subject: Re: Antenna Tuner for 20m Dipole - Build Message-ID: <%C2ye.3504$8f7.978@newsread1.news.pas.earthlink.net> Date: Mon, 04 Jul 2005 04:08:27 GMT "Cecil Moore" wrote in message news:42c877bc$1_2@spool9-west.superfeed.net... > Old Ed wrote: > > And you suggest he deliberately create a 5:1 or so SWR at the antenna > > by using a mismatched feedline, just so he can have the joy of building > > and using a tuned feeder??? Sheesh! Horses for courses, Cecil. > > I'm not familiar with the TS-830 so I assumed he had a real problem. > It's a sub-set of the same problem I solved with my 20m rotatable > dipole. I provided the same solution I presently use and with it he > gets the added bonus of 20m-10m operation. BTW, 13 cent/ft 450 ohm > ladder-line with a 9:1 SWR is a lot less lossy than 13 cent/ft coax > with an SWR of 1:1. He gets all band operation above 14 MHz and greater > efficiency for half the price. Why is that over the top? :-) > -- > 73, Cecil http://www.qsl.net/w5dxp > Hi again, Cecil... I think the "problem" here is that you tend to superimpose your priorities over those of the original questioner: "I know that I can only use it close to the cut frequency, but want to build a small tuner to allow me to go off the cut slightly. I only want the tuner to be used on 20m..." Multiband operation, while desirable in my book, was not something Kevin asked for. He also did not say he wanted the cheapest possible feedline. As to loss, if Kevin needs as much as 100 feet of feedline, and wants to use a conveniently small cable like RG-8X, he can expect to lose 1.5 dB or so. That might be a dB or so worse than window line--if the latter is in a favorable environment. Kevin would need mighty sharp ears to tell the difference. 73, Ed > > ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- > http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups > ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214815 of rec.radio.amateur.antenna Date: Sun, 03 Jul 2005 23:37:00 -0500 From: Cecil Moore Subject: Re: Can you solve this 2? References: <42c695c0$1_2@spool9-west.superfeed.net> <42c7f8f6.3567850@news.crosslink.net> <42c88135$1_1@spool9-west.superfeed.net> <8R%xe.217$Tc6.201@newssvr13.news.prodigy.com> Message-ID: <42c8bdea$1_1@spool9-west.superfeed.net> Tom Donaly wrote: > you come up with the right answer, but is your > interpretation correct? Can you do the same thing in a > general sense? If there is no Z0 match between the two > transmission lines, does your method still work? As a stand alone analysis, it yields two possible solutions but the purpose of this discussion is not to come up with a new stand alone method of analysis. The purpose is, given a standard analysis, to add TRACKING OF THE ENERGY COMPONENTS through an impedance discontinuity, something many people believe to be impossible. It wasn't designed to work as a stand alone analysis but it does for Z0-matched systems, the most usual ham configuration. However, an additional piece of information is required in the general case to be able to tell which voltage is leading and which is lagging. > (P.S. The method of using V and I and the junction of > the two xmission lines to find the forward and reverse > powers on a transmission line doesn't prove the powers exist. Do you think the powers defined in HP App Note 95-1 exist? Remember my one second long transmission line example where the number of stored joules exactly equaled the number of joules required by the forward wave and the reflected wave? If the energy is not in those waves, where is it? Nobody has provided any explaination of how standing waves can exist without forward and reflected waves. Under "standing wave", The IEEE Dictionary says: "A pure standing wave results >from the interference of two oppositely directed traveling waves of the same frequency and amplitude." i.e. standing waves are the result (effect), two oppositely directed traveling waves are the *cause*. Most of my references agree. The forward and reflected wave energy components must exist as causes before standing waves can materialize as an effect. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214816 of rec.radio.amateur.antenna Date: Mon, 04 Jul 2005 08:00:20 -0500 From: Cecil Moore Subject: Re: Tram Penetrator dipole and other things References: <1120357889.380362.40300@g49g2000cwa.googlegroups.com> <42c7e352$1_2@spool9-west.superfeed.net> <1120458850.045354.231320@f14g2000cwb.googlegroups.com> Message-ID: <42c933e3$1_1@spool9-west.superfeed.net> Blue Dawg wrote: > If I mount the Penetrator there, the very top of it might come even > with the top of the cab. I have been told, by them, whomever them is, > that the loading coil on any antenna needs to be above cab height. Seems you might be talking vhf/uhf while I am talking HF. > I am not familiar with a screwdriver antenna setup. Is it for 2-4-6 or > even 10 meter? It's all of HF. I am not familiar with the Penetrator. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! >100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- Article: 214817 of rec.radio.amateur.antenna From: mzenier@eskimo.com (Mark Zenier) Subject: Re: Evaluating location for radio activities Date: Sun, 3 Jul 2005 18:30:33 GMT Message-ID: References: In article , David wrote: >On Sun, 3 Jul 2005 17:21:29 +0200, "John Plimmer" > wrote: > >> >>Yes, the single most important location for outstanding DX on LF, MW and HF >>is to site yourself right on the beach. >>Much discussion has taken place about the "ideal" DX site and there is >>considerable consensus among serious DXer's that DXing on the waters edge at >>the beachside gives a major boost to signals. >> >>Good luck in finding the Holy Grail of DX sites >Pacific Northwest is Tsunami Country. All the good cliffs are taken. No kidding. If Guy Atkins and his friends are out at Greylands when The Big One hits, they'll be operating maritime mobile. It's a good 3-5 miles to high ground, according to my DeLorme state atlas. Mark Zenier mzenier@eskimo.com Washington State resident Article: 214818 of rec.radio.amateur.antenna From: "Ed Price" References: Subject: Re: Evaluating location for radio activities Message-ID: Date: Mon, 4 Jul 2005 10:33:58 -0700 "Mark Zenier" wrote in message news:dabofk$elp$1@eskinews.eskimo.com... > In article , > David wrote: >>On Sun, 3 Jul 2005 17:21:29 +0200, "John Plimmer" >> wrote: >> >>> >>>Yes, the single most important location for outstanding DX on LF, MW and >>>HF >>>is to site yourself right on the beach. >>>Much discussion has taken place about the "ideal" DX site and there is >>>considerable consensus among serious DXer's that DXing on the waters edge >>>at >>>the beachside gives a major boost to signals. >>> >>>Good luck in finding the Holy Grail of DX sites > >>Pacific Northwest is Tsunami Country. All the good cliffs are taken. > > No kidding. If Guy Atkins and his friends are out at Greylands when > The Big One hits, they'll be operating maritime mobile. Sounds like a old-style long-board might be good for that maritime mobile! -- Ed WB6WSN El Cajon, CA USA Article: 214819 of rec.radio.amateur.antenna From: "Lucky" Subject: Re: Evaluating location for radio activities Date: Mon, 4 Jul 2005 14:11:37 -0400 Message-ID: <11ciuur2ihrsfe2@corp.supernews.com> References: "John Plimmer" wrote in message news:da901r$er7$1@ctb-nnrp2.saix.net... > Yes, the single most important location for outstanding DX on LF, MW and > HF > is to site yourself right on the beach. > Much discussion has taken place about the "ideal" DX site and there is > considerable consensus among serious DXer's that DXing on the waters edge > at > the beachside gives a major boost to signals. > > Good luck in finding the Holy Grail of DX sites > -- > John Plimmer, Montagu, Western Cape Province, South Africa > South 33 d 47 m 32 s, East 20 d 07 m 32 s > Icom IC-756 PRO III with MW mods > RX Drake R8B, SW8 & ERGO software > Sony 7600D GE SRIII > BW XCR 30, Braun T1000, Sangean 818 & 803A. > Hallicrafters SX-100, Eddystone 940 > GE circa 50's radiogram > Antenna's RF Systems DX 1 Pro, Datong AD-270 > Kiwa MW Loop > http://www.dxing.info/about/dxers/plimmer.dx > > "Dennis Gibbs" wrote in message > news:I%Sxe.52790$R21.3417@lakeread06... >> Hello all, >> >> I am beginning the process of searching for some land on which to build a >> home. It will be located in the Pacific Northwest, in a fairly rural > area. >> I expect to indulge myself heavily in my radio hobbies, including ham > radio >> (especially on the HF bands) as well as a fair amount of Short Wave >> Listening. I would like to solicit advice on how to evaluate a potential >> location for quality of radio reception. >> >> Aside from the obvious (i.e., a high elevation, away from high voltage > power >> lines, plenty of room for antennas, etc.), are there any other attributes > I >> should consider to ensure the location will be conducive to my radio >> activities? >> >> Dennis >> R390A@Cox.net >> >> > > Hi I totally agree. I live a couple blocks from the beach, and when I take my portable down to the beach, I pick up tons of SSB frequencies. I mean a bunch. It's like the signals have an unobstructed line completely. Lucky Article: 214820 of rec.radio.amateur.antenna From: W9DMK (Robert Lay) Subject: Re: Electrical length Date: Mon, 04 Jul 2005 18:20:05 GMT Message-ID: <42c97d01.539185@news.crosslink.net> References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> On 4 Jul 2005 11:09:25 -0700, "redhat" wrote: >what is the electrical length of a transmission line in degree? > >regards > Electrical Length in degrees = 360 degrees for each wavelength divided by the velocity factor. Bob, W9DMK, Dahlgren, VA Replace "nobody" with my callsign for e-mail http://www.qsl.net/w9dmk http://zaffora/f2o.org/W9DMK/W9dmk.html Article: 214821 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Electrical length Date: Mon, 4 Jul 2005 18:52:34 +0000 (UTC) Message-ID: References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> > what is the electrical length of a transmission line in degree? > ====================================== It depends on frequency, its physical length and on its propagation velocity. Velocity Factor (VF) = Actual velocity on line / Velocity of light. It is sometimes better to refer to length in wavelengths rather than degrees. One wavelength = 360 degrees. 1/4-wave line length = 90 degrees. I'll leave somebody else to write down the actual formula for the number of degrees in a given length of line in metres, at a given frequency in MHz and given VF. I'm too tired. ---- Reg. Article: 214822 of rec.radio.amateur.antenna Date: Mon, 04 Jul 2005 13:58:20 -0500 From: Cecil Moore Subject: Re: Electrical length References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> Message-ID: <42c987cb$1_2@spool9-west.superfeed.net> Reg Edwards wrote: > I'm too tired. Me too, Reg, too much vino. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 214823 of rec.radio.amateur.antenna From: "John Smith" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> Subject: Re: Electrical length Message-ID: <5rfye.3152$Sj4.4134049@news.sisna.com> Date: Mon, 4 Jul 2005 11:43:09 -0700 0.366L(feet)F(MHz) L(degrees) = ------------------- VF --or-- 1.20L(meters)F(MHz) L(degrees) = --------------------- VF John "redhat" wrote in message news:1120500565.034856.267090@g43g2000cwa.googlegroups.com... > what is the electrical length of a transmission line in degree? > > regards > Article: 214824 of rec.radio.amateur.antenna From: "John Smith" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> <42c987cb$1_2@spool9-west.superfeed.net> Subject: Re: Electrical length Message-ID: <5Vfye.3754$tZ4.4598945@news.sisna.com> Date: Mon, 4 Jul 2005 12:15:10 -0700 Cecil: I am growing rather suspicious of you here, we seem to only hear from you when the wine glass (wine bottle?) is empty! It does bypass the argument over if half-full or half-empty, which is of a great practical assistance! ... and more wine has always fixed most of my perceived problems. Well, at least it has worked as an immediate fix--not long term however. John "Cecil Moore" wrote in message news:42c987cb$1_2@spool9-west.superfeed.net... > Reg Edwards wrote: >> I'm too tired. > > Me too, Reg, too much vino. :-) > -- > 73, Cecil http://www.qsl.net/w5dxp > > ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet > News==---- > http://www.newsfeeds.com The #1 Newsgroup Service in the World! > 120,000+ Newsgroups > ----= East and West-Coast Server Farms - Total Privacy via > Encryption =---- Article: 214825 of rec.radio.amateur.antenna From: "John Smith" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> <42c987cb$1_2@spool9-west.superfeed.net> <11cj44m9ef3lm4b@corp.supernews.com> Subject: Re: Electrical length Message-ID: Date: Mon, 4 Jul 2005 12:52:46 -0700 Jim: Yeah. Cecil is getting old, you can tell, most of us got a jump on that late hour. In California we are given a two hour head start (by PST) just to keep up with those texans! However, we don't pop the top on the bottle of viagra till 5 p.m., before that just isn't considered civilized! John "RST Engineering" wrote in message news:11cj44m9ef3lm4b@corp.supernews.com... > At 11 o'clock in the freakin' morning? > > Jim > > > "Cecil Moore" wrote in message > news:42c987cb$1_2@spool9-west.superfeed.net... >> Reg Edwards wrote: >>> I'm too tired. >> >> Me too, Reg, too much vino. :-) > =---- > > Article: 214826 of rec.radio.amateur.antenna From: "Ken Bessler" Subject: Mosely TA-33M info help Message-ID: <8nlye.7396$Eo.5443@fed1read04> Date: Mon, 4 Jul 2005 20:28:33 -0500 I just picked up a TA-33M in great shape for $100. Got 30' of Rohn 25G for another $60. I marked all the components so there will be no cunfusion but I am unclear on one point. I've got the locations of all elements marked but I need to know if the driven element is closer to the reflector or the director? I've got the boom marked where the elements go but I forgot to put a mark as to which end of the boom is "forward" hence gets the director. Also, how high (minimum) should this antenna go? I've got a friend who has one at 20' and he thinks I should try for twice that. Help? -- Just my 2¢... 73 es gd dx de Ken KGØWX Grid EM17ip, Flying Pigs #-1055 Proud builder & owner of Elecraft K2 #4913 Article: 214827 of rec.radio.amateur.antenna From: "John Smith" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> <86240$42c9cc2d$471c63fb$11132@ALLTEL.NET> Subject: Re: Electrical length Message-ID: Date: Mon, 4 Jul 2005 17:34:27 -0700 Fred: "How much string was on ball of string at the beginning" --MINUS-- "How much string is on the ball when you have cut the string off you need" = L(length of string) gessh! amateurs really should know that formula! I just hate having to unwind the ball, measure the string, then do it again after cutting! John "Fred W4JLE" wrote in message news:86240$42c9cc2d$471c63fb$11132@ALLTEL.NET... > How long is a piece of string? > > "redhat" wrote in message > news:1120500565.034856.267090@g43g2000cwa.googlegroups.com... >> what is the electrical length of a transmission line in degree? >> >> regards >> > > Article: 214828 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> <86240$42c9cc2d$471c63fb$11132@ALLTEL.NET> Subject: Re: Electrical length Date: Mon, 4 Jul 2005 22:15:24 -0400 Message-ID: The correct answer is "No, How Long is a Chinaman" "John Smith" wrote in message news:pAkye.9988$8Q.7821421@news.sisna.com... > Fred: > > "How much string was on ball of string at the beginning" --MINUS-- > "How much string is on the ball when you have cut the string off you > need" = L(length of string) > > gessh! amateurs really should know that formula! > > > I just hate having to unwind the ball, measure the string, then do it > again after cutting! > > John > > "Fred W4JLE" wrote in message > news:86240$42c9cc2d$471c63fb$11132@ALLTEL.NET... > > How long is a piece of string? > > > > "redhat" wrote in message > > news:1120500565.034856.267090@g43g2000cwa.googlegroups.com... > >> what is the electrical length of a transmission line in degree? > >> > >> regards > >> > > > > > > Article: 214829 of rec.radio.amateur.antenna From: "John" References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <11bv2l61vm5red4@corp.supernews.com> <11c0kb4s0hdg1d9@news.supernews.com> Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: Date: Mon, 4 Jul 2005 22:34:23 -0400 If an agent, a representative of an insurance company, sells and the company accepts a property then anything that happens (if fortuitous, or accidental) to that property is covered as long as it falls within the policy language, perils insured against and property covered. The company can't come back AFTER a loss and deny payment because of something not defined in the policy. They can't just make it up after the fact. 73 "Rick Scott" wrote in message news:VbWdnUxeUpeBQFjfRVn-2Q@comcast.com... >> Unfortunately, your local agent will have little or no input into any >> damage or property loss claim that you may make -- that is the adjusters >> and claim reps -- >> a whole another breed of cat (and not the domestic kind). >> If you get into personal injury or loss of life - it gets complicated >> very quickly. Fortunate that you don't have close neighbors. >> >> gb > > Yep underwriters are more than willing to add things to make more bucks. > > Getting the claim later is an all together another proposition. Article: 214830 of rec.radio.amateur.antenna From: John Ferrell Subject: Re: Rotate TriBand to vertical? Message-ID: References: Date: Sat, 02 Jul 2005 18:59:36 GMT I had not thought about pointing it up/down, I was fixated on rolling the boom. I will think on that. Thanks! John, de W8CCW On Sat, 2 Jul 2005 10:28:02 -0400, "Tam/WB2TT" wrote: > >"John Ferrell" wrote in message >news:el5bc1hseukbfhdrgn1mjf5hlnp5feojue@4ax.com... >>I have a Cushcraft A3 beam on a crank up/tilt over tower. When I tilt >> it over, it still requires a ladder to work on it due to the length of >> the elements. >> >> What I would like to do is to be able to rotate it as though I were >> trying for vertical polarization before or during the tilt over >> process. That would bring the antenna to a "flat" attitude for >> maintenance and storm protection. >> >> Any thoughts? The usual old fashioned Ham parameters apply: Little >> cost as possible, build as much as I can my self, etc...... >> >> BTW, I have several good TV rotators I might use, but none with a hole >> all the way through! >> >> de W8CCW >> >I have a Hygain TH3Mk4, which is on a 14 foot boom. What I do is to first >rotate the antenna so that when the tower is tilted down, the antenna is >pointed straight up, with the reflector parallel to the ground. I tilt the >tower until the rotator is resting on the part of an 8 foot step ladder that >the paint can is supposed to go on. This gives access to the reflector and >driven element. At that point I would take the antenna off the boom if I had >to do anything other than work on the feedline, but have had no reason to do >that. > >Here is something else you could try: drill a hole through the boom, mast, >and mounting plate, and insert a 1/4 inch bolt through the whole thing. Now, >remove the U bolts that fasten the plate to the mast. You can now swing the >boom parallel to the mast. I don't need to do this for the HyGain, but it >should work with the CushCraft. > >Tam/WB2TT > Article: 214831 of rec.radio.amateur.antenna From: Howard Subject: Re: Electrical length Date: Mon, 04 Jul 2005 20:26:30 -0700 Message-ID: References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> <86240$42c9cc2d$471c63fb$11132@ALLTEL.NET> On Mon, 4 Jul 2005 22:15:24 -0400, "Fred W4JLE" wrote: >The correct answer is "No, How Long is a Chinaman" > Yes, his is. Article: 214832 of rec.radio.amateur.antenna From: "Hal Rosser" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> Subject: Re: Electrical length Message-ID: Date: Mon, 4 Jul 2005 23:30:58 -0400 Take the line outside at night where you can hear crickets chirp. Count the number of times it chirps in 15 seconds, and add 40. Thats the degrees. (temperature). http://www.srh.noaa.gov/elp/wxcalc/formulas/cricketChirp.html Now measure the transmission line, Then get a copy of the ARRL Antenna Handbook or the ARRL Amateur Radio handbook, and find out why you asked the wrong question. "redhat" wrote in message news:1120500565.034856.267090@g43g2000cwa.googlegroups.com... > what is the electrical length of a transmission line in degree? > > regards > Article: 214833 of rec.radio.amateur.antenna From: "John Smith" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> <86240$42c9cc2d$471c63fb$11132@ALLTEL.NET> Subject: Re: Electrical length Message-ID: Date: Mon, 4 Jul 2005 17:40:40 -0700 Fred: I should have pointed out: It is easier and quicker to work with small balls, than large balls--of string. The women seem especially good when it comes to this, I am studying them closely to see why. John "Fred W4JLE" wrote in message news:86240$42c9cc2d$471c63fb$11132@ALLTEL.NET... > How long is a piece of string? > > "redhat" wrote in message > news:1120500565.034856.267090@g43g2000cwa.googlegroups.com... >> what is the electrical length of a transmission line in degree? >> >> regards >> > > Article: 214834 of rec.radio.amateur.antenna From: "Ed Price" References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <11bv2l61vm5red4@corp.supernews.com> <11c0kb4s0hdg1d9@news.supernews.com> Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: Date: Mon, 4 Jul 2005 22:53:34 -0700 "John" wrote in message news:Wkmye.61939$%Z2.8135@lakeread08... > If an agent, a representative of an insurance company, sells and the > company accepts a property then anything that happens (if fortuitous, or > accidental) to that property is covered as long as it falls within the > policy language, perils insured against and property covered. > > The company can't come back AFTER a loss and deny payment because of > something not defined in the policy. They can't just make it up after the > fact. > > 73 I'll bet that there's "language in the policy" that is sufficiently vague and flexible such that the company can stretch a loophole for anything that it wants. Maybe I'm too paranoid, but the insurance company expects that an insured property is a normal and typical example of materials and construction, and that due care was applied to the design. Further, the property should be in compliance with local existing building codes and standards. If you wired half your house with lamp cord, never got a permit, and have no record of inspection, do you think the company agent should know this by himself? If the loss is big enough, and especially if there's some unusual circumstances (fire inspector's report, neighbor's claims), then the company's lawyers have plenty of room to work in. You may have the utmost confidence in your own workmanship, but, if the insurance company is trying to avoid a $500k claim, all they have to do is say "no." So then what happens? You take the insurance company to court, and they ask you about your experience in soils engineering, concrete construction, structural engineering, calculation of wind loading, welding certifications, experience with lightning protection, etc. They will cut you up into very small pieces. Everything unusual about your property should be defined, and if your agent is still eager to sell you a policy despite your "creative engineering", then I would start to wonder why the agent is so desperate to sell policies. -- Ed WB6WSN El Cajon, CA USA Article: 214835 of rec.radio.amateur.antenna From: Ron Subject: Re: AD5TH Tower Project Completed - Pics Online Date: 05 Jul 2005 12:00:56 EDT Message-ID: <42CAAF91.50507@yahoo.com> References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <11bv2l61vm5red4@corp.supernews.com> <11c0kb4s0hdg1d9@news.supernews.com> <4Uxye.1368$BK1.479@newsread3.news.pas.earthlink.net> Hank Oredson wrote: > "Ed Price" wrote in message > news:Ifpye.27243$ro.18610@fed1read02... > >>"John" wrote in message >>news:Wkmye.61939$%Z2.8135@lakeread08... >> >>>If an agent, a representative of an insurance company, sells and the >>>company accepts a property then anything that happens (if fortuitous, or >>>accidental) to that property is covered as long as it falls within the >>>policy language, perils insured against and property covered. >>> >>>The company can't come back AFTER a loss and deny payment because of >>>something not defined in the policy. They can't just make it up after the >>>fact. >>> >>>73 >> >>I'll bet that there's "language in the policy" that is sufficiently vague >>and flexible such that the company can stretch a loophole for anything >>that it wants. Maybe I'm too paranoid, but the insurance company expects >>that an insured property is a normal and typical example of materials and >>construction, and that due care was applied to the design. Further, the >>property should be in compliance with local existing building codes and >>standards. >> >>If you wired half your house with lamp cord, never got a permit, and have >>no record of inspection, do you think the company agent should know this >>by himself? If the loss is big enough, and especially if there's some >>unusual circumstances (fire inspector's report, neighbor's claims), then >>the company's lawyers have plenty of room to work in. You may have the >>utmost confidence in your own workmanship, but, if the insurance company >>is trying to avoid a $500k claim, all they have to do is say "no." So then >>what happens? You take the insurance company to court, and they ask you >>about your experience in soils engineering, concrete construction, >>structural engineering, calculation of wind loading, welding >>certifications, experience with lightning protection, etc. They will cut >>you up into very small pieces. >> >>Everything unusual about your property should be defined, and if your >>agent is still eager to sell you a policy despite your "creative >>engineering", then I would start to wonder why the agent is so desperate >>to sell policies. > > > > Um ... let me guess ... you don't carry a general liability rider? > Or if you do, you were not careful to read the details? > > They are not expensive, and will cover anything ... and can even > cover intentional neglegence by the owner. Every ham with a tower > (or a pool, or horses, or a big dog, or ...) should have one. > Yes but you need everything first insurance with one company and then at the maximum but the minimums. You pay dearly for a general liability rider if you take it all into account. Yes you are protected. Article: 214836 of rec.radio.amateur.antenna Message-ID: <313030303837383542CAD10809@zetnet.co.uk> Date: Tue, 5 Jul 2005 18:27:20 +0100 From: Dave Piggin Subject: Re: Support for a 90 ft folded dipole - suggestions References: > I want to raise the centre of my 91 ft folded dipole to at least 35 > feet. I live on the west coast of Florida with all the attendant > possibilities of hurricanes. I cannot afford a retractable tower and do > not have room for proper guy wires. I want to be able to put a pulley > at the top so I am able to lower the antenna in the event of high > winds. I have a cement block house with a roof peak of about 16 feet, > I would prefer not to have to pour a base for the "mast". > I would appreciate any advice on supporting the "mast" to the house > wall and what material to use for the "mast" so that it might not be > permanently bent by 125 mph winds. > Any constructive help gratefully welcomed Hey, I take it you guys don't have military surplus outlets? Surely !! What about pump up field masts and the like.......... Otherwise square steel tube reducing in diameter size until you achieve the required total height. Using a piece of heavy steel plate, 900mmx900mm, obtain a 150mm length of box section just wider than your bottom box section piece and weld that section to the plate [ your bottom section sits in this ] Drill a hole straight through this to accommodate a bolt through both box sections [ stops the section being lifted out ] Weld a plate that will accommodate a galvanized hand winch [ the type used on boat trailers ] to the largest bottom section, weld an eye to the top smallest box section [ the winching cable attaches to this ] Leaving at least 600mm in each extended section, fabricate a collar that will lock each section in place as it is risen upwards [ to stop it falling ] Or weld two nuts on each top section side, drilling the centres away for a bolt/set screw to fix through, which will then stop the box sections from sliding back down. Choose a cable of suffcient winching breaking strain. Crank away until the desired height is obtained, locking each section in place. Reverse the procedure for dropping down. Attach any guy wires to additional eyes on various sections, which should be welded on at each section top. Choose a secure and fixed location for the floor plate. If you don't utilise or need a floor plate, fabricate fixings that will be able for the bottom section to be fixed to the wall [ stand off's ] Sounds a big job but it's easy done and not megga bucks either. Not knowing what a 125MPH hurricane is like in the UK, do's it make yer jowls chatter in the wind? LOL Hey Bobs yer uncle, job done. Cheers Dave -- Amateur Radio Call Sign M1BTI, Located in Manchester England. Locator square IO83TK Chairman Of Trafford Radio Club. Club Call Signs G0TRG & M1BBP Located at Umist, University Of Manchester Institute For Science And Technology Share What You Know, Learn What You Don't. Article: 214837 of rec.radio.amateur.antenna Date: Tue, 05 Jul 2005 14:44:47 -0500 From: Cecil Moore Subject: Re: AD5TH Tower Project Completed - Pics Online References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <11bv2l61vm5red4@corp.supernews.com> <11c0kb4s0hdg1d9@news.supernews.com> <4Uxye.1368$BK1.479@newsread3.news.pas.earthlink.net> Message-ID: <42cae42f_2@spool9-west.superfeed.net> Hank Oredson wrote: > Um ... let me guess ... you don't carry a general liability rider? > Or if you do, you were not careful to read the details? > > They are not expensive, and will cover anything ... and can even > cover intentional neglegence by the owner. Every ham with a tower > (or a pool, or horses, or a big dog, or ...) should have one. ... or kids. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 214838 of rec.radio.amateur.antenna From: "Roger Conroy" Subject: Re: Electrical length Date: Tue, 5 Jul 2005 20:06:39 +0200 Message-ID: References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> "Hal Rosser" wrote in message news:X8nye.34929$qm.24764@bignews5.bellsouth.net... > Take the line outside at night where you can hear crickets chirp. > Count the number of times it chirps in 15 seconds, and add 40. > Thats the degrees. (temperature). > http://www.srh.noaa.gov/elp/wxcalc/formulas/cricketChirp.html Ummmm..... You have to specify the species of cricket. Each species has a characteristic chirp factor. Also are your degrees F, C or K? Article: 214839 of rec.radio.amateur.antenna From: "John Smith" References: <11bsdqpir7o54fa@news.supernews.com> Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: <6xBye.14610$xO3.14771332@news.sisna.com> Date: Tue, 5 Jul 2005 12:51:22 -0700 Charlie: Bet when you started out, you would never have thought so many petty hams existed. All you need to do is beef up that setup a bit and smile at all the losers here. Jealous "old women hams" of a envious and vindictive nature. Just laugh a bit when they sit out there eating the signal off the 90 foot beast. Perhaps you can, once in a awhile, be kind and offer to, "Let them sit on it!" John "Charlie" wrote in message news:11bsdqpir7o54fa@news.supernews.com... > 75 ft guyed tower with 21 foot mast. 2M M2 HO LOOP antenna at 95 > ft. M2 2M9SSB beam antenna at 90 ft. > The difference from antennas at around 30 ft to the same antennas at > 90-95 ft is astonishing. Anyone considering raising their antennas > should "just do it" > > 1. http://deepsouthnet.net/tower.html > > I am founder and net control for the Deep South 2 Meter SSB Net > located in Union,Mississippi. Come join us 7 nights a week at 8:30PM > CDT on 144.240 MHz USB. We have 10-15 or more check-ins nightly > with 38 on our All Time Total Roster and nearly 25 on our Active > Roster! The net has grown from it's first Roll Call on April > 8,2005 at an amazing rate. > > -- > > Charlie > Ham Radio - AD5TH > www.ad5th.com > Deep South 2 Meter SSB Net > www.deepsouthnet.net > > > > > > Article: 214840 of rec.radio.amateur.antenna From: Yodar Subject: Re: Feed Line Length - Ladder Line References: <3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net> Message-ID: <0DDye.141591$VH2.135782@tornado.tampabay.rr.com> Date: Tue, 05 Jul 2005 22:14:20 GMT Pat Whelton wrote: > I've had a store bought (so sue me) dipole fed with 600 ohm ladder line up > 35 feet for about a year and a half now and I love this antenna. It's 66 > feet in length and I can pretty much tune everything from 40 through 10 > meters with a Dentron Super Tuner. This thing came with 50 feet of ladder > line and I have it draped all over the place trying to take up the slack > before it finally feeds into the shack. > > My question is can I safely cut some of this excess ladder line off? I > assume that it will impact the tuning but I'm also assuming the tuner will > take care of it. I guess I can always cut it off and if it doesn't work I > can wire nut it back together again. It just looks sloppy with all this > extra feed line drooping off the roof and suspended by the fence (and over > to grandma's house we go) before it finally comes into the shack. > > Your thoughts are appreciated. > > I'M SHOPPING FOR SUCH AN ANTENNA Who sells it? specs, price etc. remove nospam Yodar in O'do jstrain4nospam@cfl.rr.com Article: 214841 of rec.radio.amateur.antenna From: "Charlie" Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Tue, 5 Jul 2005 19:44:21 -0500 Message-ID: <11cmacogllv4q16@news.supernews.com> References: <11bsdqpir7o54fa@news.supernews.com> <6xBye.14610$xO3.14771332@news.sisna.com> Hi John and thanks for those remarks.... Well no I did not expect so many "petty hams" but it is just human nature and the heart of man I suppose to be that way for some folks. Tropical storm Cindy is coming our way now and I'll see how the tower holds up. I can sure tell everyone and anyone that the difference from 30 ft to 90-95ft is really astonishing. I doubt this smile will leave my face for some time. 73 / DX -- Charlie Ham Radio - AD5TH www.ad5th.com Deep South 2 Meter SSB Net www.deepsouthnet.net "John Smith" wrote in message news:6xBye.14610$xO3.14771332@news.sisna.com... > Charlie: > > Bet when you started out, you would never have thought so many petty hams > existed. > > All you need to do is beef up that setup a bit and smile at all the losers > here. Jealous "old women hams" of a envious and vindictive nature. > > Just laugh a bit when they sit out there eating the signal off the 90 foot > beast. > > Perhaps you can, once in a awhile, be kind and offer to, "Let them sit on > it!" > > John > > "Charlie" wrote in message > news:11bsdqpir7o54fa@news.supernews.com... >> 75 ft guyed tower with 21 foot mast. 2M M2 HO LOOP antenna at 95 ft. M2 >> 2M9SSB beam antenna at 90 ft. >> The difference from antennas at around 30 ft to the same antennas at >> 90-95 ft is astonishing. Anyone considering raising their antennas >> should "just do it" >> >> 1. http://deepsouthnet.net/tower.html >> >> I am founder and net control for the Deep South 2 Meter SSB Net located >> in Union,Mississippi. Come join us 7 nights a week at 8:30PM CDT on >> 144.240 MHz USB. We have 10-15 or more check-ins nightly with 38 on our >> All Time Total Roster and nearly 25 on our Active Roster! The net has >> grown from it's first Roll Call on April 8,2005 at an amazing rate. >> >> -- >> >> Charlie >> Ham Radio - AD5TH >> www.ad5th.com >> Deep South 2 Meter SSB Net >> www.deepsouthnet.net >> >> >> >> >> >> > > Article: 214842 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Feed Line Length - Ladder Line Message-ID: <90jmc194dk5rsieg574n3mtdgbqvvmoh52@4ax.com> References: <3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net> <0DDye.141591$VH2.135782@tornado.tampabay.rr.com> Date: Wed, 06 Jul 2005 03:14:53 GMT On Tue, 05 Jul 2005 22:14:20 GMT, Yodar wrote: >Pat Whelton wrote: >> I've had a store bought (so sue me) dipole fed with 600 ohm ladder line up >> 35 feet for about a year and a half now and I love this antenna. It's 66 >> feet in length and I can pretty much tune everything from 40 through 10 >> meters with a Dentron Super Tuner. This thing came with 50 feet of ladder >> line and I have it draped all over the place trying to take up the slack >> before it finally feeds into the shack. >> >> My question is can I safely cut some of this excess ladder line off? I >> assume that it will impact the tuning but I'm also assuming the tuner will >> take care of it. I guess I can always cut it off and if it doesn't work I >> can wire nut it back together again. It just looks sloppy with all this >> extra feed line drooping off the roof and suspended by the fence (and over >> to grandma's house we go) before it finally comes into the shack. >> >> Your thoughts are appreciated. >> >> >I'M SHOPPING FOR SUCH AN ANTENNA > > Who sells it? specs, price etc. > >remove nospam >Yodar in O'do >jstrain4nospam@cfl.rr.com he probably has one of the 600-ohm fed dipoles from www.w7fg.com try their web site. there are also lots of dipole kits at www.thewireman.com or get the arrl's antenna book & do-it-yrself. fun. bob k5qwg Article: 214843 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Support for a 90 ft folded dipole - suggestions Message-ID: References: Date: Wed, 06 Jul 2005 03:18:21 GMT On Sat, 02 Jul 2005 14:22:51 GMT, none@none.com wrote: >I want to raise the center of my 91 ft folded dipole to at least 35 >feet. I live on the west coast of Florida with all the attendant >possibilites of hurricanes. I cannot afford a retractable tower and do >not have room for proper guy wires. I want to be able to put a pulley >at the top so I am able to lower the antenna in the event of high >winds. I have a cement block house with a roof peak of about 16 feet, >I would prefer not to have to pour a base for the "mast". >I would appreciate any advice on supporting the "mast" to the house >wall and what material to use for the "mast" so that it might not be >permanantly bent by 125 mph winds. > >Any constructive help gratefully welcomed There's a nice A-frame wood mast in the ARRL Handbook that's about 40 feet high, and can be made from just a few pieces of lumber. Bob k5qwg Article: 214844 of rec.radio.amateur.antenna From: "Hal Rosser" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> Subject: Re: Electrical length Message-ID: Date: Tue, 5 Jul 2005 23:54:55 -0400 > > Ummmm..... You have to specify the species of cricket. Each species has a > characteristic chirp factor. > Also are your degrees F, C or K? > This is from http://www.noblenet.org/reference/crickets.htm The formula for this is to count the number of chirps in 15 seconds and add 39 to calculate the temperature (degrees Farenheit.) If there are 30 chirps in 15 seconds, the temperature should be about 69 degrees F. This formula is said to be accurate within one degree. A variation is to count the chirps in 13 seconds, and add 40. Sources: "Cricket thermometers," Field & Stream, July 1993, Vol. 98 Issue 3, p21. and from http://www.almanac.com/outdoors/crickets.php we have this: To convert cricket chirps to degrees Fahrenheit, count number of chirps in 14 seconds then add 40 to get temperature. Example: 30 chirps + 40 = 70° F To convert cricket chirps to degrees Celsius, count number of chirps in 25 seconds, divide by 3, then add 4 to get temperature. Example: 48 chirps /(divided by) 3 + 4 = 20° C =========== there's apparently a small descrepancy (1 degree) in the sources. Article: 214845 of rec.radio.amateur.antenna From: "Arnold Schwarzenegger" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> Subject: Re: Electrical length Date: Tue, 5 Jul 2005 21:00:08 -0700 Message-ID: only girly men count cricket chirps arnold "Hal Rosser" wrote in message news:eBIye.40185$Tt.36707@bignews3.bellsouth.net... > > >> Ummmm..... You have to specify the species of cricket. Each species >> has a >> characteristic chirp factor. >> Also are your degrees F, C or K? >> > > This is from > http://www.noblenet.org/reference/crickets.htm > > The formula for this is to count the number of chirps in 15 seconds > and add > 39 to calculate the temperature (degrees Farenheit.) If there are 30 > chirps > in 15 seconds, the temperature should be about 69 degrees F. This > formula is > said to be accurate within one degree. A variation is to count the > chirps in > 13 seconds, and add 40. > Sources: > "Cricket thermometers," Field & Stream, July 1993, Vol. 98 Issue 3, > p21. > > > > and from http://www.almanac.com/outdoors/crickets.php > > we have this: > > To convert cricket chirps to degrees Fahrenheit, count number of > chirps in > 14 seconds then add 40 to get temperature. > Example: 30 chirps + 40 = 700 F > > To convert cricket chirps to degrees Celsius, count number of chirps > in 25 > seconds, divide by 3, then add 4 to get temperature. > Example: 48 chirps /(divided by) 3 + 4 = 200 C > > =========== > > there's apparently a small descrepancy (1 degree) in the sources. > > > Article: 214846 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: dipole question Date: Tue, 05 Jul 2005 23:47:01 -0700 Message-ID: <11cmvjb5jvlt692@corp.supernews.com> References: <1120620023.203039.55420@g44g2000cwa.googlegroups.com> The short answer is no. One of the best readily-available ferrites for VHF use is Fair-Rite type 61. At 6 meters, one core of this material will look like a resistor of a few ohms in parallel with an inductor whose reactance is also a few ohms. That combination won't do what you're asking. Even if you locate a better material, you'll still only have a few ohms of reactance for a single core at that frequency, and the Q is likely to still be not very good. It'll be a long way from making a trap, which is what you're trying to do. Roy Lewallen, W7EL pdrunen@aol.com wrote: > Hi Group, > > Let's say I have a 15 meter dipole. If I were to take a ferrite core > and place a core along the dipole for the lenght of 6 meters, having > two cores on either side. > > The question is would this antenna now work as a dipole on 6 meters but > not on 15 unless the reactance of the core was low at 21 MHz? > > Does the core act as a RF block but not as a inductance with a > reactance at 15meters? > > If it is a inductive reactance, then reducting the lenght of the dipole > would bring down swr on 15m. > > I have seen the ferrite emi cores which clamp around the wire, would > these work for 100 watts? > > If I had a way to move the cores along the dipole, I could create a > multiband antenna, true? > > I am sure there are better ways to do such, aka trap dipole but I like > to give this some thought. > > De KJ4UO > Article: 214847 of rec.radio.amateur.antenna From: Buck Subject: Re: dipole question Date: Wed, 06 Jul 2005 07:47:55 -0400 Message-ID: <3ngnc1140l4nh70tcbhnogsferah3mip66@4ax.com> References: <1120620023.203039.55420@g44g2000cwa.googlegroups.com> On 5 Jul 2005 20:20:23 -0700, "pdrunen@aol.com" wrote: >Hi Group, > >Let's say I have a 15 meter dipole. If I were to take a ferrite core >and place a core along the dipole for the lenght of 6 meters, having >two cores on either side. > >The question is would this antenna now work as a dipole on 6 meters but >not on 15 unless the reactance of the core was low at 21 MHz? > >Does the core act as a RF block but not as a inductance with a >reactance at 15meters? > >If it is a inductive reactance, then reducting the lenght of the dipole >would bring down swr on 15m. > >I have seen the ferrite emi cores which clamp around the wire, would >these work for 100 watts? > >If I had a way to move the cores along the dipole, I could create a >multiband antenna, true? > >I am sure there are better ways to do such, aka trap dipole but I like >to give this some thought. > >De KJ4UO If you want to have a single antenna for 15 meters and 6 meters, you may find it easiest and more efficient to do what I did with my 20 meter dipole. I cut a 6 meter dipole and hung it under my 20 meter dipole. I happened to cut the length perfect for 50.125, which is about where I wanted it. The 20 meter dipole resonance dropped. however, it was a bit on the high side, a perfect match for 14.336 before hanging the 6 meter dipole. now it is a bit lower, but it is broad banded enough to cover the entire band at 1.3:1 or less so I didn't need to trim it. The two dipoles come together at the coax connector and an 8" piece of PVC pipe is used as an insulator and hangs from the 20 meter dipole to the end of the 6 meter dipole to keep the ends away from the 20 meter dipole. I have been making and using antennas like this since I was a novice. The only thing I have ever noticed different from single dipoles is that the lower bands are more broad-banded on the parallel dipoles. BTW, the six meter dipole is great. It doesn't compare to my neighbors with beams, but it is better than nothing, and it is a dipole. -- 73 for now Buck N4PGW Article: 214848 of rec.radio.amateur.antenna From: "AAA RF Products" Subject: New Coax Connector & Adapter Catalog Now Available Message-ID: Date: Wed, 6 Jul 2005 06:36:25 -0700 Please email or call for your free copy of our latest coax connector, adapter, cable assembly & bulk coaxial cable catalog. No minimum order No handling fees. web: www.aaarfproducts.com email: sales@aaarfproducts.com call: 949 481 3154 fax: 949 388 5448 mail: AAA RF Products, 949 Calle Amanecer, San Clemente, CA 92673 USA Article: 214850 of rec.radio.amateur.antenna From: Allodoxaphobia Subject: Re: dipole question Date: 6 Jul 2005 14:48:54 GMT Message-ID: References: <1120620023.203039.55420@g44g2000cwa.googlegroups.com> <3ngnc1140l4nh70tcbhnogsferah3mip66@4ax.com> On Wed, 06 Jul 2005 07:47:55 -0400, Buck wrote: > On 5 Jul 2005 20:20:23 -0700, "pdrunen@aol.com" > wrote: > >>Hi Group, >> >>Let's say I have a 15 meter dipole. If I were to take a ferrite core >>and place a core along the dipole for the lenght of 6 meters, having >>two cores on either side. >> >>The question is would this antenna now work as a dipole on 6 meters but >>not on 15 unless the reactance of the core was low at 21 MHz? > > If you want to have a single antenna for 15 meters and 6 meters, you > may find it easiest and more efficient to do what I did with my 20 > meter dipole. I cut a 6 meter dipole and hung it under my 20 meter > dipole. A dipole cut for the low end of 40M should work "OK" (for selected definitions of "OK") on both 15M and 6M, as well. I often work fellas on 6M who apologize for "using a 40M dipole." Their sigs are usually every bit as strong as others. 73 Jonesy -- Marvin L Jones | jonz | W3DHJ | linux Pueblo, Colorado | @ | Jonesy | OS/2 __ | config.com | DM78rf | SK Article: 214851 of rec.radio.amateur.antenna From: "Christopher O'Callaghan" Subject: A car with 6 antennas Date: Wed, 6 Jul 2005 16:29:15 +0100 Message-ID: never saw a car with 6 big antennas(3-4 feet)and 3 small ones all on mag mounts...WOW Article: 214852 of rec.radio.amateur.antenna Date: Wed, 06 Jul 2005 10:31:29 -0500 From: Cecil Moore Subject: Re: dipole question References: <1120620023.203039.55420@g44g2000cwa.googlegroups.com> <3ngnc1140l4nh70tcbhnogsferah3mip66@4ax.com> Message-ID: <42cbfa51$1_2@spool9-west.superfeed.net> Allodoxaphobia wrote: > I often work fellas on 6M who apologize for "using a 40M dipole." > Their sigs are usually every bit as strong as others. For a 40m dipole running North/South, the major lobes on 6m would be N27W, N27E, S27W, S27E, i.e. pretty much end fire. I use my 20m rotatable dipole as an emergency TV antenna when cable is down. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Article: 214853 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Wed, 6 Jul 2005 12:16:23 -0400 Message-ID: <11co0u5kch91hbd@corp.supernews.com> References: <11bsdqpir7o54fa@news.supernews.com> <6xBye.14610$xO3.14771332@news.sisna.com> <42CBDF40.38F9CFED@gmail.com> Dear Rick (N7HJT): Who is the subject of your message? 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "R. Scott" wrote in message news:42CBDF40.38F9CFED@gmail.com... > Charlies typing style - Check > Supports Charlie 100% - Check > Never Posted on Net before (except 3 messages on how to post direct to > newsgroups) - Check > SAME NEWSSERVER As charlie - Check > > Yep, Back to your old tricks again. > When are you going to FAKE other hams Names again. Article: 214854 of rec.radio.amateur.antenna From: "John Smith" References: <11bsdqpir7o54fa@news.supernews.com> <6xBye.14610$xO3.14771332@news.sisna.com> <1120660466.321576.164590@o13g2000cwo.googlegroups.com> Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: Date: Wed, 6 Jul 2005 07:53:05 -0700 Rick: Do you know the difference between a real amateur and a goof ball which thinks everyone wants to be an engineer? Do you know the difference between an individual who can get along with others and enjoys communicating with them, and them with he--as opposed to someone which is drain on the groups energy? Do you know the difference between someone who doesn't wish to impose his thoughts on someone else and one who does? Do you know the difference between someone who enjoys life and having fun and someone just sitting their trying to look half-way intelligent by telling everyone else what it wrong with everything in the world? Get a real life. Look around you, it is quite apparent that people, your neighbors and those around you will have the same opinion of you which we form here. A leopard cannot change his spots, these social disabilities you pack through life with you are a burden on those around you. Get a therapist and get some help son. John "Rick Scott" wrote in message news:1120660466.321576.164590@o13g2000cwo.googlegroups.com... > So Mr SMITH > > In your Expert Opinion, and full 100% support of Charlie, let us see > your Calculations that this thing is Safe. Im not a tower expert by > any means. But working at the Worlds largest Aircraft company as a > technical Design Engineer, I know what looks BAD. AND I have helped > put many towers up and climbed my share of towers, and I know what > is > safe and what isnt. I would not go up that one for any money on > earth. > > Tell me what those trees can hold in upward pulling momentum from > those > 3 guy lines, and how that thing has not exceeded the capacity for > the > trees to not eventually SNAP. Tell me how the Power pole, set in > the > verticle with, will hold those three guy lines perfectly secure, > while > they are pulling at it in a side and upward movement How with no > secure pins are the turnbuckles not going to give way. > > The force of the tower alone in the wind and pulling on those trees > is > enough to make one Queesy just to look at it. Oh and He still > hasnt > answered what he plans to tell the Power company when they discover > his > little field mod to thier power pole. Hell its a 200 buck fine if > they see you putting a nail in one here. > > So please do tell us again Mr Smith. > Article: 214855 of rec.radio.amateur.antenna From: "John Smith" References: <11bsdqpir7o54fa@news.supernews.com> <6xBye.14610$xO3.14771332@news.sisna.com> <1120660466.321576.164590@o13g2000cwo.googlegroups.com> <1120676230.552202.119280@o13g2000cwo.googlegroups.com> Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: Date: Wed, 6 Jul 2005 13:05:37 -0700 Rick: Get something straight here. You will NOT be telling me what to do, or setting up little cute tricks to bait me into your game. You can sit there like a fool and attempting all the manipulations you care to--indeed, you can sit there till hell freezes over. I can't believe you people, does this chit really work on other people? Get a life! Go find some bum on the street, perhaps he will play your game with you for a bit of pocket change... ROFLOL! John "Rick Scott" wrote in message news:1120676230.552202.119280@o13g2000cwo.googlegroups.com... > >> Get a therapist and get some help son. > > Typical, Rather than answer the questions on the issues at hand > attack > the poster in some Veiled attempt and being superior. Sorry dont > need a > therapist or help. > > Charlie came here posting his tower crowing to the world about his > install and asked for opionions. When He got quite the opposite of > what he thought was glowing props he whined. And now you come in > supporting him 100% and even sound like him. > > > Heck you even post from exactly the same Posting site as him. Are > you > RELATED? > Article: 214856 of rec.radio.amateur.antenna From: "George Washington Bush" References: <11bsdqpir7o54fa@news.supernews.com> <6xBye.14610$xO3.14771332@news.sisna.com> <1120660466.321576.164590@o13g2000cwo.googlegroups.com> <1120676230.552202.119280@o13g2000cwo.googlegroups.com> Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Wed, 6 Jul 2005 13:09:42 -0700 Message-ID: the man is right rich see a therapist get a life your country and your president is behind you son now be on about it G.W.B. "Rick Scott" wrote in message news:1120676230.552202.119280@o13g2000cwo.googlegroups.com... > >> Get a therapist and get some help son. > > Typical, Rather than answer the questions on the issues at hand > attack > the poster in some Veiled attempt and being superior. Sorry dont > need a > therapist or help. > > Charlie came here posting his tower crowing to the world about his > install and asked for opionions. When He got quite the opposite of > what he thought was glowing props he whined. And now you come in > supporting him 100% and even sound like him. > > > Heck you even post from exactly the same Posting site as him. Are > you > RELATED? > > Article: 214857 of rec.radio.amateur.antenna From: "Hal Rosser" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> Subject: Re: Electrical length Message-ID: Date: Wed, 6 Jul 2005 16:39:39 -0400 Yah That's why I use a thermometer - - or - make Arnold count the chirps for me. He's a real chirpinator "Arnold Schwarzenegger" wrote in message news:ir7wmcjgcvulegj.050720052100@kirk... > only girly men count cricket chirps > > arnold > Article: 214858 of rec.radio.amateur.antenna From: "George Washington Bush" References: <1120500565.034856.267090@g43g2000cwa.googlegroups.com> Subject: Re: Electrical length Date: Wed, 6 Jul 2005 14:13:25 -0700 Message-ID: <4qmkdpfrb723j7u.060720051413@kirk> Hal; Now don't be picking on my good buddy arnie, he is doing a fine job out there in california for me. We need him to get those drivers licenses for the illegal aliens. By this time next year I would like to have all the truck drivers which are buying homes, cars and sending their children through college reduced to receiving welfare checks. It doesn't take a genius to drive a truck and that is one of the last areas a working fellow can still earn a half decent living, time for those illegals to start driving those big rigs for a minimum wage. With those illegals living 10 family's to a home they can get by on a lot less. Get with the plan man. We used to export our standard of living to the rest of the world pulling them out from under poverty, disease and death, but that got darn tiring (and our profits from ripping them off under that system were too low.) We replaced that tired old plan with the new one, 'import 3'rd world conditions to america.' Now get out there, support your president, your congress and the supreme court and employ an illegal alien today. I am counting on you to be a team player here hal. Now put down those silly crickets and the thermometer and get to work man! G.W.B. "Hal Rosser" wrote in message news:bjXye.46379$Tt.26779@bignews3.bellsouth.net... > Yah > That's why I use a thermometer - > - or - make Arnold count the chirps for me. > He's a real chirpinator > > > > "Arnold Schwarzenegger" wrote in message > news:ir7wmcjgcvulegj.050720052100@kirk... >> only girly men count cricket chirps >> >> arnold >> > > > Article: 214859 of rec.radio.amateur.antenna From: "Walter Maxwell" References: Subject: Re: A car with 6 antennas Message-ID: Date: Wed, 6 Jul 2005 17:36:43 -0400 "Dave" wrote in message news:Euydnbm6CoQoYlbfRVn-pw@crocker.com... > then you have never been to any decent sized hamfest/fleamarket. > > "Christopher O'Callaghan" wrote in message > news:dagtcc$dt9$1@reader01.news.esat.net... > > never saw a car with 6 big antennas(3-4 feet)and 3 small ones all on mag > > mounts...WOW He was probably conducting a mutual impedance measuring test to see which one would out couple the other. Walt,W2DU Article: 214860 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: A car with 6 antennas Message-ID: <2okoc1d8tqkqjrmappgf1t55s0t3q5eo9e@4ax.com> References: Date: Wed, 06 Jul 2005 21:59:03 GMT On Wed, 6 Jul 2005 15:58:35 -0000, "Dave" wrote: >then you have never been to any decent sized hamfest/fleamarket. > >"Christopher O'Callaghan" wrote in message >news:dagtcc$dt9$1@reader01.news.esat.net... >> never saw a car with 6 big antennas(3-4 feet)and 3 small ones all on mag >> mounts...WOW >> >> >> > Or seen a San Antonian cop drive by with 17 tiny aeraels sticking up >from his cruiser roof, looking like a dead cockroach. Those guys must use a lotta radios... bob k5qwg Article: 214861 of rec.radio.amateur.antenna From: Owen Subject: Calculating loss on a mismatched line Message-ID: Date: Wed, 06 Jul 2005 22:07:41 GMT Apparently, Michaels described in "Technical Correspondence" in QST NOV 1997 a method for calculating loss on a mismatched line. I don't have the article, and haven't been able to find it on the net, so I am working from references to it that I have seen, mainly in Usenet. Apparently, the method involves calculation of a factor (let's call it MR) as MR=|(Zl-Zo*)/(Zl+Zo)|, and the line loss between two points is given by 10*log((1-MR1**2)/(1-MR2**2)) where MR1 and MR2 are the values for MR at points 1 and 2. I have compared the results of this on lines with Xo<0 and high VSWR, and the results are identical to calcuating the loss by subtraction of Real(VI*) at point 1 from Real(VI*) at point 2. Has anyone a link to, or a reference to the derivation of the formula? Owen -- Article: 214862 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: A car with 6 antennas Date: Wed, 06 Jul 2005 15:15:23 -0700 Message-ID: <11com00fa5n1r74@corp.supernews.com> References: That's really just one antenna with six feedpoints. Roy Lewallen, W7EL Article: 214863 of rec.radio.amateur.antenna From: Buck Subject: Re: A car with 6 antennas Date: Wed, 06 Jul 2005 18:26:55 -0400 Message-ID: References: On Wed, 6 Jul 2005 16:29:15 +0100, "Christopher O'Callaghan" wrote: >never saw a car with 6 big antennas(3-4 feet)and 3 small ones all on mag >mounts...WOW > > You missed mine when it had 8 antennas on it, or when I was in atlanta with 10 antennas. -- 73 for now Buck N4PGW Article: 214864 of rec.radio.amateur.antenna From: Owen Subject: Re: Calculating loss on a mismatched line Message-ID: References: Date: Wed, 06 Jul 2005 22:27:08 GMT On Wed, 06 Jul 2005 22:07:41 GMT, Owen wrote: > >Apparently, the method involves calculation of a factor (let's call it >MR) as MR=|(Zl-Zo*)/(Zl+Zo)|, and the line loss between two points is >given by 10*log((1-MR1**2)/(1-MR2**2)) where MR1 and MR2 are the >values for MR at points 1 and 2. Sorry, that gives the additional loss "due to SWR" which has to be added to the matched line loss to obtain the total loss between points 1 and 2. Zl in the formulas is the impedance (V/I) at the point where MR is calculated. Owen -- Article: 214865 of rec.radio.amateur.antenna From: "Walter Maxwell" References: Subject: Re: Calculating loss on a mismatched line Message-ID: <3%Yye.13220$Si3.1138@fe06.lga> Date: Wed, 6 Jul 2005 18:32:50 -0400 "Owen" wrote in message news:limoc1pl0c47tqc886j56h9gfuopo5irt5@4ax.com... > On Wed, 06 Jul 2005 22:07:41 GMT, Owen wrote: > > > > >Apparently, the method involves calculation of a factor (let's call it > >MR) as MR=|(Zl-Zo*)/(Zl+Zo)|, and the line loss between two points is > >given by 10*log((1-MR1**2)/(1-MR2**2)) where MR1 and MR2 are the > >values for MR at points 1 and 2. > > Sorry, that gives the additional loss "due to SWR" which has to be > added to the matched line loss to obtain the total loss between points > 1 and 2. > > Zl in the formulas is the impedance (V/I) at the point where MR is > calculated. > > Owen Well, Owen, you might take a look at Appendix 8 of Reflections 2, which can be found on my web site at w2du.com. Click on 'Read Appendices from Reflections 2', the click on Appendix 8. I think what you'll see there will be of interest. Walt, W2DU Article: 214866 of rec.radio.amateur.antenna From: Me Subject: Re: A car with 6 antennas References: <11com00fa5n1r74@corp.supernews.com> Message-ID: Date: Wed, 06 Jul 2005 22:41:25 GMT In article <11com00fa5n1r74@corp.supernews.com>, Roy Lewallen wrote: > That's really just one antenna with six feedpoints. > > Roy Lewallen, W7EL Maybe a Phased Array for signal tracking........ Me who used to drive one of those for the FCC........... Article: 214867 of rec.radio.amateur.antenna From: "H. Adam Stevens, NQ5H" Subject: Re: A car with 6 antennas Date: Wed, 6 Jul 2005 18:01:30 -0500 Message-ID: <11coomcq9n75661@corp.supernews.com> References: Walt is always the tru guru. Chuckle. 73 OM H. NQ5H "Walter Maxwell" wrote in message news:saYye.234$zA.139@fe04.lga... > > "Dave" wrote in message > news:Euydnbm6CoQoYlbfRVn-pw@crocker.com... >> then you have never been to any decent sized hamfest/fleamarket. >> >> "Christopher O'Callaghan" wrote in message >> news:dagtcc$dt9$1@reader01.news.esat.net... >> > never saw a car with 6 big antennas(3-4 feet)and 3 small ones all on >> > mag >> > mounts...WOW > > He was probably conducting a mutual impedance measuring test to see which > one would out couple the other. > > Walt,W2DU > > Article: 214868 of rec.radio.amateur.antenna From: Owen Subject: Re: Calculating loss on a mismatched line Message-ID: References: <3%Yye.13220$Si3.1138@fe06.lga> Date: Wed, 06 Jul 2005 23:01:26 GMT On Wed, 6 Jul 2005 18:32:50 -0400, "Walter Maxwell" wrote: >Well, Owen, you might take a look at Appendix 8 of Reflections 2, which can >be found on my web site at w2du.com. Click on 'Read Appendices from >Reflections 2', the click on Appendix 8. I think what you'll see there will >be of interest. Thanks Walt. I had a look at it, and although it doesn't state as much, isn't it correct only for distortionless lines (Xo=0)? Owen -- Article: 214869 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: New program. Two SWR meters. Date: Wed, 6 Jul 2005 23:12:36 +0000 (UTC) Message-ID: This program models the behaviour of a transmission line plus antenna. The line impedance can have any Zo. The antenna feedpoint impedance can be any value of R+jX. Line length can be any fraction and number of wavelengths. Line overall attenuation can be any value of dBs. There is an SWR meter located at each end of the line. The meters also indicate the reflection coefficients at the locations. Meter Zo can be set equal to line Zo or to the standard 50 ohms. Line input impedance can be observed to change versus line length in wave-lengths, line attenuation and antenna impedance. The transforming action of the line can be demonstrated. The smaller SWR and reflection coefficient at the transmitter end of the line can be seen. The exact increase in loss due to standing waves on the line is calculated. The program can be used in practical applications and also for educational purposes. It is hoped it may prevent the outbreaks in violence which frequently occur in newsgroups about the meanings of SWR and the notions of reflected power. Download program SWRARGUE from website below in a few seconds. File size = 41 Kbytes. Run immediately. No unzipping inconvenience. ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 214870 of rec.radio.amateur.antenna From: "John Smith" References: Subject: Re: New program. Two SWR meters. Message-ID: <3FZye.69$Rq1.3947655@news.sisna.com> Date: Wed, 6 Jul 2005 16:18:03 -0700 Reg: Great idea for a program but, I don't like the name. Would you consider renaming it: SWR-PISSING-MATCH.exe John "Reg Edwards" wrote in message news:dahoh4$kaa$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com... > This program models the behaviour of a transmission line plus > antenna. > The line impedance can have any Zo. The antenna feedpoint impedance > can be any value of R+jX. Line length can be any fraction and > number > of wavelengths. Line overall attenuation can be any value of dBs. > > There is an SWR meter located at each end of the line. The meters > also > indicate the reflection coefficients at the locations. Meter Zo can > be set equal to line Zo or to the standard 50 ohms. > > Line input impedance can be observed to change versus line length in > wave-lengths, line attenuation and antenna impedance. The > transforming > action of the line can be demonstrated. The smaller SWR and > reflection > coefficient at the transmitter end of the line can be seen. The > exact > increase in loss due to standing waves on the line is calculated. > > The program can be used in practical applications and also for > educational purposes. It is hoped it may prevent the outbreaks in > violence which frequently occur in newsgroups about the meanings of > SWR and the notions of reflected power. > > Download program SWRARGUE from website below in a few seconds. File > size = 41 Kbytes. Run immediately. No unzipping inconvenience. > ---- > ........................................................... > Regards from Reg, G4FGQ > For Free Radio Design Software go to > http://www.btinternet.com/~g4fgq.regp > ........................................................... > > Article: 214871 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: New program. Two SWR meters Date: Wed, 6 Jul 2005 23:21:26 +0000 (UTC) Message-ID: This program models the behaviour of a transmission line plus antenna. The line impedance can have any Zo. The antenna feedpoint impedance can be any value of R+jX. Line length can be any fraction and number of wavelengths. Line overall attenuation can be any value of dBs. There is an SWR meter located at each end of the line. The meters also indicate the reflection coefficients at the locations. Meter Zo can be set equal to line Zo or to the standard 50 ohms. Line input impedance can be observed to change versus line length in wave-lengths, line attenuation and antenna impedance. The transforming action of the line can be demonstrated. The smaller SWR and reflection coefficient at the transmitter end of the line can be seen. The exact increase in loss due to standing waves on the line is calculated. The program can be used in practical applications and also for educational purposes. It is hoped it may prevent the outbreaks in violence which frequently occur in newsgroups about the meanings of SWR and the notions of reflected power. Download program SWRARGUE from website below in a few seconds. File size = 41 Kbytes. Run immediately. No unzipping inconvenience. ---- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 214872 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Calculating loss on a mismatched line Date: Wed, 6 Jul 2005 23:48:53 +0000 (UTC) Message-ID: References: Owen, Your formula is too short to be anything but an approximation. It may be a very good approximation. On the other hand it may contain exactly the same errors as whatever you may have checked it against. The exact formula is exceedingly involved and occupies about half a dozen lines of source code in new program SWRARGUE which by coincidence I have just placed in my website. You can check your formula against my program. Let us know how you get on. ---- Reg, G4FGQ --------------------------------------------------------------- "Owen" wrote in message news:e1loc1554j1hec26o62l5c7sn5ugublgrp@4ax.com... > > Apparently, Michaels described in "Technical Correspondence" in QST > NOV 1997 a method for calculating loss on a mismatched line. > > I don't have the article, and haven't been able to find it on the net, > so I am working from references to it that I have seen, mainly in > Usenet. > > Apparently, the method involves calculation of a factor (let's call it > MR) as MR=|(Zl-Zo*)/(Zl+Zo)|, and the line loss between two points is > given by 10*log((1-MR1**2)/(1-MR2**2)) where MR1 and MR2 are the > values for MR at points 1 and 2. > > I have compared the results of this on lines with Xo<0 and high VSWR, > and the results are identical to calcuating the loss by subtraction of > Real(VI*) at point 1 from Real(VI*) at point 2. > > Has anyone a link to, or a reference to the derivation of the formula? > > Owen > -- Article: 214873 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: New program. Two SWR meters. Date: Wed, 6 Jul 2005 23:52:24 +0000 (UTC) Message-ID: References: <3FZye.69$Rq1.3947655@news.sisna.com> "John Smith" wrote in message news:3FZye.69$Rq1.3947655@news.sisna.com... > Reg: > > Great idea for a program but, I don't like the name. > > Would you consider renaming it: > SWR-PISSING-MATCH.exe > > ------------------------------------------------------------- Unfortunately, DOS filenames are restricted to a maximum of 8 characters. ---- Reg Article: 214874 of rec.radio.amateur.antenna From: Yodar Subject: Re: Feed Line Length - Ladder Line References: <3AVxe.429$BK1.219@newsread3.news.pas.earthlink.net> <0DDye.141591$VH2.135782@tornado.tampabay.rr.com> <1120605853.135291.115510@z14g2000cwz.googlegroups.com> Message-ID: Date: Wed, 06 Jul 2005 23:54:05 GMT > > Yodar wrote: >> >>I'M SHOPPING FOR SUCH AN ANTENNA >> >> Who sells it? specs, price etc. >> >>remove nospam >>Yodar in O'do >>jstrain4nospam@cfl.rr.com > > > Yodar, where are you shopping? Go to Lowes or Home Depot and get #14 > stranded wire, plexiglas for insulators, and screws, nuts and bolts to > put it together. Get some 450 ohm ladder line (Wireman, w7fg I think), > or make your own from wire and PVC from Lowes. To put the whole thing > together should be 30 minutes or less, I do it every year at field day. > Make the dipole as long and high (within reason) as you have room for, > and the 450 ohm line long enough to get from the antenna feedpoint to > your tuner. There you have what you have been shopping for. > Radioworks among other folks have pre-put together antennas, but > where is the fun in that? > Gary N4AST > Thank you for the clues. The 66' length and 10-40 M was very attractive. This is for SWL only ! (apartment attached) We HAVE an Ham Radio Supply branch store in O'do from whom i bought a Grundig R350 a while back. their antennas were overkill for my application and TOOOO BIG! Had been using a vertical slinky but it really poopsout above 40M Yodar Article: 214875 of rec.radio.amateur.antenna From: Owen Subject: Re: Calculating loss on a mismatched line Message-ID: <2kroc19319ui4fk7q6b2im6k4fda47s136@4ax.com> References: Date: Wed, 06 Jul 2005 23:56:26 GMT On Wed, 6 Jul 2005 23:48:53 +0000 (UTC), "Reg Edwards" wrote: >Owen, > >Your formula is too short to be anything but an approximation. It may >be a very good approximation. On the other hand it may contain >exactly the same errors as whatever you may have checked it against. > >The exact formula is exceedingly involved and occupies about half a >dozen lines of source code in new program SWRARGUE which by >coincidence I have just placed in my website. I have calculated the loss using P=Real(V*I*) at the two points, and it is long winded. Michaels approach produces the same result, and the coding is more elegant, probably faster to calculate. He is a SK, so I can't ask him, but in the hope that it is well known, someone might know of the derivation. > >You can check your formula against my program. Let us know how you get >on. Your calculator does not allow complex Zo does it? Doesn't that mean it assumes a distortionless line. I am calculating loss in the general case. Thanks... Owen -- Article: 214876 of rec.radio.amateur.antenna From: "John Smith" References: <3FZye.69$Rq1.3947655@news.sisna.com> Subject: Re: New program. Two SWR meters. Message-ID: Date: Wed, 6 Jul 2005 17:00:42 -0700 Reg: TOUCHÉ! I stand corrected... LOL! John "Reg Edwards" wrote in message news:dahqro$68j$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com... > > "John Smith" wrote in message > news:3FZye.69$Rq1.3947655@news.sisna.com... >> Reg: >> >> Great idea for a program but, I don't like the name. >> >> Would you consider renaming it: >> SWR-PISSING-MATCH.exe >> >> > ------------------------------------------------------------- > > Unfortunately, DOS filenames are restricted to a maximum of 8 > characters. > ---- > Reg > > Article: 214877 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <3%Yye.13220$Si3.1138@fe06.lga> Subject: Re: Calculating loss on a mismatched line Message-ID: Date: Wed, 6 Jul 2005 20:06:13 -0400 "Owen" wrote in message news:miooc1dkd6cj93rvh181no9cg9o28vkc6k@4ax.com... > On Wed, 6 Jul 2005 18:32:50 -0400, "Walter Maxwell" > wrote: > > >Well, Owen, you might take a look at Appendix 8 of Reflections 2, which can > >be found on my web site at w2du.com. Click on 'Read Appendices from > >Reflections 2', the click on Appendix 8. I think what you'll see there will > >be of interest. > > Thanks Walt. I had a look at it, and although it doesn't state as > much, isn't it correct only for distortionless lines (Xo=0)? > Owen > As I understand it, Owen, a line has to be lossless for Xo to be 0, while distortionless lines have loss but have equal series R and shunt G. All lines that I've measured have a small negative X, that would be zero if the line were lossless. So I'd have to say that the material in Appendix is is correct for standard lines. Distortionless lines are normally found only in long-distance phone lines used at voice frequencies, not RF. Or am I missing something? Walt,W2DU Article: 214878 of rec.radio.amateur.antenna From: "John Smith" References: <2kroc19319ui4fk7q6b2im6k4fda47s136@4ax.com> Subject: Re: Calculating loss on a mismatched line Message-ID: Date: Wed, 6 Jul 2005 17:08:33 -0700 Owen: Right of you to be cautious of that wise and crafty old brit. Not only has he survived in this den of treacherous and particularly vicious hams--he has THRIVED--this is quite suspicious in itself! However, most often you will find there is true wisdom in his words and programs... and it is of a highly practical nature. He is a welcomed resource here... John "Owen" wrote in message news:2kroc19319ui4fk7q6b2im6k4fda47s136@4ax.com... > On Wed, 6 Jul 2005 23:48:53 +0000 (UTC), "Reg Edwards" > wrote: > >>Owen, >> >>Your formula is too short to be anything but an approximation. It >>may >>be a very good approximation. On the other hand it may contain >>exactly the same errors as whatever you may have checked it against. >> >>The exact formula is exceedingly involved and occupies about half a >>dozen lines of source code in new program SWRARGUE which by >>coincidence I have just placed in my website. > > I have calculated the loss using P=Real(V*I*) at the two points, and > it is long winded. Michaels approach produces the same result, and > the > coding is more elegant, probably faster to calculate. He is a SK, so > I > can't ask him, but in the hope that it is well known, someone might > know of the derivation. > >> >>You can check your formula against my program. Let us know how you >>get >>on. > > Your calculator does not allow complex Zo does it? Doesn't that mean > it assumes a distortionless line. I am calculating loss in the > general > case. > > Thanks... > > Owen > > -- Article: 214879 of rec.radio.amateur.antenna From: "Walter Maxwell" References: Subject: Re: New program. Two SWR meters Message-ID: Date: Wed, 6 Jul 2005 20:11:28 -0400 "Reg Edwards" wrote in message news:dahp1m$18h$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com... > This program models the behaviour of a transmission line plus antenna. > The line impedance can have any Zo. The antenna feedpoint impedance > can be any value of R+jX. Line length can be any fraction and number > of wavelengths. Line overall attenuation can be any value of dBs. > > There is an SWR meter located at each end of the line. The meters also > indicate the reflection coefficients at the locations. Meter Zo can > be set equal to line Zo or to the standard 50 ohms. > > Line input impedance can be observed to change versus line length in > wave-lengths, line attenuation and antenna impedance. The transforming > action of the line can be demonstrated. The smaller SWR and reflection > coefficient at the transmitter end of the line can be seen. The exact > increase in loss due to standing waves on the line is calculated. > > The program can be used in practical applications and also for > educational purposes. It is hoped it may prevent the outbreaks in > violence which frequently occur in newsgroups about the meanings of > SWR and the notions of reflected power. > > Download program SWRARGUE from website below in a few seconds. File > size = 41 Kbytes. Run immediately. No unzipping inconvenience. > ---- > ........................................................... > Regards from Reg, G4FGQ > For Free Radio Design Software go to > http://www.btinternet.com/~g4fgq.regp > ........................................................... Reg, the two SWR meters, one at each of the line, follows precisely the method I presented in Appendix 8 of Reflections 2 to explain how to determine the additional line attenuation attributed to SWR. Appendix 8 can be found on my web site at w2du.com. Click on 'Read Appendices from Reflections 2', then click on Appendix 8. Walt, W2DU Article: 214880 of rec.radio.amateur.antenna From: Owen Subject: Re: Calculating loss on a mismatched line Message-ID: <25toc1129od79tf8anm67h16an9fajpit1@4ax.com> References: <3%Yye.13220$Si3.1138@fe06.lga> Date: Thu, 07 Jul 2005 00:22:32 GMT On Wed, 6 Jul 2005 20:06:13 -0400, "Walter Maxwell" wrote: >As I understand it, Owen, a line has to be lossless for Xo to be 0, while >distortionless lines have loss but have equal series R and shunt G. All Walt, I learnt that a distortionless line is one where attenuation and phase velocity are constant for all frequencies, and that requires that R/XL=G/XC in the RLGC model of a lines characteristics, and the result is that Zo is purely real. A lossless line is a special case of a distortionless line. >lines that I've measured have a small negative X, that would be zero if the >line were lossless. So I'd have to say that the material in Appendix is is >correct for standard lines. Distortionless lines are normally found only in >long-distance phone lines used at voice frequencies, not RF. Or am I missing >something? If you like, I am saying your approach is valid for lossless lines, it is also valid for all distortionless lines, but I think it is not accurate for lines in the general case because it isn't correct if Xo!=0. Owen --