Article: 214419 of rec.radio.amateur.antenna From: Owen Subject: Re: Receiving loop antenna design References: <1lCte.69055$HI.40107@edtnps84> Message-ID: Date: Sat, 25 Jun 2005 00:34:23 GMT Reg Edwards wrote: > "Owen" wrote > >>Reg, I mentioned in an earlier post that I was concerned about the >>estimate of the loop inductance. > > > Owen, > > The HF inductance of a square loop is - > > L = 0.8 * H * ( Ln( 4 * H / D ) - 1.467 ) microhenries, > > where H is length of one side, > > and D is diameter of circular conductor, > > both dimensions are in metres. > Though it looks a little different, that formula will always produce exactly the same results as the one that I have used. > There are half a dozen other formulas which at first appear to be > different from the above but can be mathematically transformed to be > identical. And then there are imperial and metric units. > > I got it out of one of one of my old notebooks. It's what I use in my > programs. I think I stole it from Terman. And Terman stole it from > Grover. So it's sure to be accurate enough for anything you are ever > likely to use it for. I looked in Terman, but didn't find it, and still can't. I might be blind! I got it from http://emcsun.ece.umr.edu/new-induct/ but it obviously shares the same root as yours. They attribute it to Grover. > > It is obviously an approximation because when a large conductor > diameter is comparable with a very short length of side, the > inductance has a negative value. Understood. > > As a sanity check, compare it with whatever formula you have used up > to now. See above. I think you are telling me I should be confident I am sane. If it was just that easy! Now I just have to find someone with access to an OATS to measure one of these things. Thanks Reg... Owen Article: 214420 of rec.radio.amateur.antenna From: "Fred W4JLE" References: Subject: Re: regolazione antenna Date: Fri, 24 Jun 2005 20:43:00 -0400 Message-ID: <614fc$42bca895$438df14a$7179@ALLTEL.NET> Translation: I would want to know how to establish the best position of an antenna for optimal reception "Hal Rosser" wrote in message news:E71ve.2652$gr.1363@bignews1.bellsouth.net... > > "Nico" wrote in message > news:y8wue.32955$b5.1435976@news3.tin.it... > > > > vorrei sapere come si fa a stabilire la migliore posizione dell'antenna > per > > un'ottima ricezione > > ... > > That's easy for you to say. > I can make out the word 'antenna', and 'Dell' and something like > Rice-a-Roni. > So - to answer your question - > If you spill Rice-a-Roni on your antenna, it won't hurt too bad, but it will > probably hurt the Dell computer. > > Article: 214421 of rec.radio.amateur.antenna Date: Fri, 24 Jun 2005 19:44:13 -0500 From: Cecil Moore Subject: Re: rich and Cecil momentum"Sloshing" EM Energy References: <42b337fc$1_1@spool9-west.superfeed.net> <18548-42B486DF-562@storefull-3256.bay.webtv.net> <1119188334.322677.10230@g49g2000cwa.googlegroups.com> <42bb6e3c$1_2@spool9-west.superfeed.net> Message-ID: <42bca9d5$1_2@spool9-west.superfeed.net> ml wrote: > then i think quantum things but even if i expertly understood all > these parts, would I have the answers?? (Quote from Max Planck) "A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it." -- 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: 214422 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: offset diople antenna Date: Fri, 24 Jun 2005 17:52:54 -0700 Message-ID: <11bpan6pobgvq5c@corp.supernews.com> References: <_K6dncKmBLpD0SHfRVn-uQ@rogers.com> Chuck Olson wrote: > > Hi, Larry, > > An off-center fed antenna doesn't necessarily produce unbalanced feeder > currents - - I'm sorry to say, it does. There's coupling from the feedline to each side of the antenna, and unlike a symmetrical dipole with feedline at right angles, the coupling from each side is unequal. This results in unbalanced feeder currents. If the feedline is twinlead or open wire line, this shows up as unequal currents on the two conductors. On coax it manifests itself as current on the outside of the shield. In both cases, the result is the same -- feedline radiation. This can be shown quite dramatically by simple modeling. I've also seen it myself by direct measurement(*). A current balun (NOT voltage balun) at the feedpoint will reduce the conducted common mode current just as it will with a dipole, but you still have to deal with common mode current due to coupling. Depending on the frequency and the feedline length and orientation, you might get lucky and not have too much feedline current. On the other hand, it can be bad enough to aggravate RFI problems if the feedline is routed near power or telephone lines, or cause trouble with your rig or shack accessories. > just a different feeding impedance level, which he will no > doubt take care of with a tuner or a 4:1 ratio in the balun if single band > use is all he wants and he can find the right spot for the feeder. Of course > the balun takes care of any unbalance that might be due to the feeder > not making a 90 degree angle with the antenna. There's nothing wrong > with his idea. See above comments. Routing the feeder at right angles to the antenna doesn't eliminate current due to mutual coupling, and neither does a feedpoint balun. >. . . (*) You'll find some measured values of feedline current and more discussion about it in "The Off-Center-Fed Dipole Revisited: A Broadband, Multiband Antenna" by John Belrose, VE2CV and Peter Bouliane, VE3KLO, QST, Aug. 1990. Roy Lewallen, W7EL Article: 214423 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: Using the matchbox Date: Fri, 24 Jun 2005 17:57:23 -0700 Message-ID: <11bpavkng2gkfd3@corp.supernews.com> References: <1119554991.240126.47990@g49g2000cwa.googlegroups.com> <1119618054.991193.201730@z14g2000cwz.googlegroups.com> <42bc1ddf$1_2@spool9-west.superfeed.net> Richard Clark wrote: > . . . > Ptolemy also reduced much of his theory of Astronomy and Optics to > geometric construction techniques in many Handbooks and offered scads > of tables of observations - some of which were condemned by Newton: > "[Ptolemy] developed certain astronomical theories and discovered > that they were not consistent with observation. Instead of > abandoning the theories, he deliberately fabricated observations > from the theories so that he could claim that the observations > prove the validity of his theories. In every scientific or > scholarly setting known, this practice is called fraud, and it is > a crime against science and scholarship." > . . . How ironic! I recall an article in _Scientific American_ many years ago which presented credible evidence that Newton himself fudged his data. The author argued, and gave examples to show, that some of Newton's data were much too accurate and consistent for the techniques and equipment he used. Roy Lewallen, W7EL Article: 214424 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <11bhb2khc92phf0@corp.supernews.com> <20290-42B8E899-1291@storefull-3255.bay.webtv.net> Subject: Re: How to measure soil constants at HF Message-ID: <7a3ve.5467$B_3.113@fe05.lga> Date: Fri, 24 Jun 2005 22:18:42 -0400 This is a multi-part message in MIME format. ------=_NextPart_000_004B_01C5790A.AF1C79C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable "Reg Edwards" wrote in message = news:d9h6q9$iss$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com... >=20 > "Ian White GM3SEK" wrote >=20 >> That was an administrative policy decision rather than a technical > one. >> From the technical viewpoint, everybody agrees that 120*0.25wl is > more >> than enough to override the local ground conditions under the tower >> irrelevant. >> > = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >=20 > - - - - and since soil resistivity decreases with increasing > frequency, and the impedance due to soil capacitance also decreases > with increasing frequency, everybody agrees that 1/8th wavelength or > less is more than long enough. Reg, do you really mean what you said above, 'soil resistivity decreases = with increasing frequency'? Are you sure you didn't mean soil = conductivity decreases with increasing frequency? In my experience with = AM BC antennas I've found that conductivity decreases, not resistivity.=20 The FCC charts showing signal level vs conductivity and frequency = overwhelmingly show conductivity decreasing with frequency. So you ask, = what proof is there that the FCC charts are correct? Well, Reg, soil = conductivity measurements of thousands of AM antenna systems world wide = have proved them correct. As an example that I posted a few days ago, consider the coverage area = >from afforded by a single 1/4wl vertical radiating 250 watts at 550 KHz = with a signal strength of 1 mv/meter at one mile and a conductivity of = 8. If the frequency were raised to 1500 KHz with a 1/4wl vertical at = that frequency, the power required to cover the same area is 47 KW. =20 Does this example indicate a decreasing soil resitivity with increasing = frequency or a decreasing soil conductivity? Walt, W2DU ------=_NextPart_000_004B_01C5790A.AF1C79C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
"Reg Edwards" <g4fgq.regp@ZZZbtinternet.com> wrote=20 in message news:d9h6q9$iss$1@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com...
>
> "Ian White GM3SEK" =20 wrote
>
>> That was an administrative policy decision = rather=20 than a technical
> one.
>>  From the technical = viewpoint,=20 everybody agrees that 120*0.25wl is
> more
>> than enough = to=20 override the local ground conditions under the tower
>>=20 irrelevant.
>>
> = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>=20
> - - - -  and since soil resistivity decreases with=20 increasing
> frequency, and the impedance due to soil capacitance = also=20 decreases
> with increasing frequency, everybody agrees that 1/8th = wavelength or
> less is more than long enough.
 
Reg, do you really mean what you said=20 above, 'soil resistivity decreases with increasing frequency'? Are = you sure=20 you didn't mean soil conductivity decreases with increasing = frequency? In=20 my experience with AM BC antennas I've found that conductivity = decreases, not=20 resistivity.
 
The FCC charts showing signal level vs = conductivity=20 and frequency overwhelmingly show conductivity decreasing with = frequency. So you=20 ask, what proof is there that the FCC charts are correct? Well, Reg, = soil=20 conductivity measurements of thousands of AM antenna systems world wide = have=20 proved them correct.
 
As an example that I posted a few days = ago,=20 consider the coverage area from afforded by a single 1/4wl vertical=20 radiating 250 watts at 550 KHz with a signal strength of 1 mv/meter = at=20 one mile and a conductivity of 8. If the frequency were raised = to 1500=20 KHz with a 1/4wl vertical at that frequency, the power required to cover = the=20 same area is 47 KW.  
 
Does this example indicate a decreasing = soil=20 resitivity with increasing frequency or a decreasing=20 soil conductivity?
 
Walt, W2DU
------=_NextPart_000_004B_01C5790A.AF1C79C0-- Article: 214425 of rec.radio.amateur.antenna From: "Hal Rosser" References: <614fc$42bca895$438df14a$7179@ALLTEL.NET> Subject: Re: regolazione antenna Message-ID: Date: Fri, 24 Jun 2005 22:54:34 -0400 "Fred W4JLE" wrote in message news:614fc$42bca895$438df14a$7179@ALLTEL.NET... > Translation: > I would want to know how to establish the best position of an antenna for > optimal reception Kool - New answer based on that translation: Best position is Up HIGH!!! big altitude on top of bigum pole maximus hight sky-high Article: 214426 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: offset diople antenna Date: Sat, 25 Jun 2005 04:12:32 +0000 (UTC) Message-ID: References: <_K6dncKmBLpD0SHfRVn-uQ@rogers.com> I'm not quite clear what you are talking about, but the impedance seen looking into the feedpoint of a 1/2-wave resonant dipole when the feedpoint is at the centre, is a purely resistive 70 to 73 ohms. As the feedpoint is moved away from the centre the impedance rapidly increases (approximately proportional to the square of the offset) BUT REMAINS PURELY RESISTIVE until, as the feedpoint nears the end of the dipole, it rises to several thousand ohms, purely resistive. This is the impedance which terminates the twin feedline. But if there is a choke in the line at this point then the choke can be considered to be a short length of line of the same length and Zo as is wound on the choke. The short length of line on the choke will then TRANSFORM the antenna input impedance to a somwhat different value to terminate the line. (For the purpose of calculating SWR on the line, and the line's input impedance, etc.) Now carry on from there. ;o) ---- Reg, G4FGQ "Chuck Olson" wrote in message news:Iradne3JiLfrGCHfRVn-sA@comcast.com... > > "larry" wrote in message > news:_K6dncKmBLpD0SHfRVn-uQ@rogers.com... > > Greetings > > > > A gentleman on another group.. is telling me that he wants to put up an > > offset dipole antenna and feed it with a balum.. He is a new amateur and I > > can tell he does't have much antenna knowledge... > > > > He is being advise to use an offset antenna wich in my mind isn't the best > > answer to his problem.... > > > > Does anyone know of a website that describes the offset antenna better > than > > I can.... > > > > Larry ve3fxq > > Hi, Larry, > > An off-center fed antenna doesn't necessarily produce unbalanced feeder > currents - - just a different feeding impedance level, which he will no > doubt take care of with a tuner or a 4:1 ratio in the balun if single band > use is all he wants and he can find the right spot for the feeder. Of course > the balun takes care of any unbalance that might be due to the feeder > not making a 90 degree angle with the antenna. There's nothing wrong > with his idea. > > I just typed it balum, too, so don't be concerned - - we all make typos. > > 73, Chuck W6PKP > > > > Article: 214427 of rec.radio.amateur.antenna From: "J. Mc Laughlin" Subject: Re: Using the matchbox Date: Sat, 25 Jun 2005 00:22:28 -0400 Message-ID: <11bpmtiaq7flee@corp.supernews.com> References: <1119554991.240126.47990@g49g2000cwa.googlegroups.com> <1119618054.991193.201730@z14g2000cwz.googlegroups.com> <42bc1ddf$1_2@spool9-west.superfeed.net> <11bpavkng2gkfd3@corp.supernews.com> ... and, while I may have misplaced the place where this happened (I could have heard this when I was at U of Manchester), it seems that an extensive set of early measurements of c were deliberately "sorted" and produced an expected value and std that was outside of the actual value of c. When the logbooks containing all of the measurements were consulted many decades later, it was found that if one used all of the measurements the actual expected value of c was within the expected error. It is late and I have not quite said everything right. The (old) published expected c and its std were well outside of the actual c. When the old data was used in its entirety, the newly calculated expected c and its std encompassed the actual value of c. (Note "expected" has a technical meaning.) The moral is to keep a complete log and be honest. It is much more easy to do both when one has numbers. Before some of my work at Ohio State, one had to extract numbers from strip chart recordings using slave labor. Mac (who should be in bed) N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: JCM@Power-Net.Net "Roy Lewallen" wrote in message news:11bpavkng2gkfd3@corp.supernews.com... > Richard Clark wrote: > > . . . > > Ptolemy also reduced much of his theory of Astronomy and Optics to > > geometric construction techniques in many Handbooks and offered scads > > of tables of observations - some of which were condemned by Newton: > > "[Ptolemy] developed certain astronomical theories and discovered > > that they were not consistent with observation. Instead of > > abandoning the theories, he deliberately fabricated observations > > from the theories so that he could claim that the observations > > prove the validity of his theories. In every scientific or > > scholarly setting known, this practice is called fraud, and it is > > a crime against science and scholarship." > > . . . > > How ironic! I recall an article in _Scientific American_ many years ago > which presented credible evidence that Newton himself fudged his data. > The author argued, and gave examples to show, that some of Newton's data > were much too accurate and consistent for the techniques and equipment > he used. > > Roy Lewallen, W7EL Article: 214428 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: How to measure soil constants at HF Date: Sat, 25 Jun 2005 05:42:31 +0000 (UTC) Message-ID: References: <11bhb2khc92phf0@corp.supernews.com> <20290-42B8E899-1291@storefull-3255.bay.webtv.net> <7a3ve.5467$B_3.113@fe05.lga> Walter, Your ancient charts, which I think I have once seen but don't now have ready access to, apply to LF. Permittivity was ignored when they were calculated. The curves were intended to be used as a guide, better than nothing, rather than the Bible on the subject. But amateurs are concerned with what happens at HF. There are a lot of MHz between 16 KHz, 500 KHz and 40 MHz I think the discrepancy about conductivity vs frequency is due to simplification of the equivalent circuit of soil which, in its most simple form, is a resistor in shunt with a capacitor. As frequency increases the capacitative impedance decreases and drags the equivalent resistive component down with it. There is a significant decrease at around 7 MHz. At 30 or 40 MHz the soil has changed from being mainly resistive at LF to being mainly capacitative and not nearly so lossy. The capacitance between a pair of 1 metre square plates, spaced 1 metre apart, is only 8.8 pF. But when muliplied by the permittivity of damp soil the impedance at 30 MHz is quite low. The permittivity of water is 80. Simple conductivity does not apply. We are not talking about the same things. Actually, its not worth arguing about. The uncertainty in soil characteristics is plus or minus 30 or 40 percent. And it makes less than 1 S-unit difference to the performance of radials and Eznec take off angles at HF. No doubt Roy will disagree as a matter of Boston Tea Party principles. And Richard, KB7QHC, will spin off at a tangent into Shakesperian verse. Hope this clarifies my Altzeimer's thoughts on the matter. ---- Reg, G4FGQ Article: 214429 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: How to measure soil constants at HF Date: Sat, 25 Jun 2005 07:56:38 +0000 (UTC) Message-ID: References: <11bhb2khc92phf0@corp.supernews.com> <20290-42B8E899-1291@storefull-3255.bay.webtv.net> <7a3ve.5467$B_3.113@fe05.lga> "Richard Clark" wrote in message news:vptpb1dl52464l44vebachnu36do3jphbf@4ax.com... > On Sat, 25 Jun 2005 05:42:31 +0000 (UTC), "Reg Edwards" > wrote: > > >Richard, KB7QHC, will spin off at a tangent into Shakesperian verse. > > Hi Reg, > > Let's draw a chord between 3 soil samples to see how fruitless knowing > "How to measure soil constants at HF" really is: > > You are in farm country where the annual rainfall is 835mm. Where the > mean temperature is 12.8°C. Where the soil is 20% sand, 65% silt, and > 15% clay. > > What is the Conductivity in the 80M band? > > You are in farm country where the annual rainfall is 360mm. Where the > mean temperature is 4.9°C. Where the soil is 65% sand, 20% silt, and > 15% clay. > > What is the Conductivity in the 80M band? > > You are in farm country where the annual rainfall is 790mm. Where the > mean temperature is 6.9°C. Where the soil is 31% sand, 33% silt, and > 36% clay. > > What is the Conductivity in the 80M band? > > OR > > We return to our regularly scheduled "More Les Dames d'Escoffier > Recipes with your host Punchinello." Today we discuss packing coaxial > tubes with meringue to measure propagation delay for custards. > > 73's > Richard Clark, KB7QHC ==================================== I don't know. And neither do you or anybody else. If you DID know you would not have the foggiest idea what to do with the data anyway. I might! Havn't I recently said the uncertainty in ascertaining soil characteristics is in the order of 30 to 40 percent and not worth arguing or making yourself appear ridiculous about. There's missing data. You forgot the iron oxide content and soil permeability. ---- Punchinello. Article: 214430 of rec.radio.amateur.antenna From: Mark Subject: Correct cable for 920Mhz Mobile, Yagi Date: Sat, 25 Jun 2005 11:19:42 +0200 Message-ID: Please could somebody tell me the best cable (compromise between cost and loss) for use with an external Yagi antenna connected to a mobile phone. I live in a Very poor reception area, and I need to fit an external antenna. I have found somewhere that sells 10 element Yagi's, and I can mount the thing as high as need be, but I read somewhere that the longer the connecting cable, can negate the benefits of long mounting poles. I have freinds in the surrounding area that have the same problem, so I could do with a "rule of thumb" that I can use for fitting these things. The shop where I got the antenna from is offering me RG58 cable for this purpose, which is cheap enough, but is it the best compromise for what I am trying to achieve? Your assistance would be most welcome. Mark Article: 214431 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: How to measure soil constants at HF Date: Sat, 25 Jun 2005 02:42:51 -0700 Message-ID: <11bq9oriipqncd8@corp.supernews.com> References: <11bhb2khc92phf0@corp.supernews.com> <20290-42B8E899-1291@storefull-3255.bay.webtv.net> Reg Edwards wrote: > . . . > The attenuation due to skin effect and wire inductance along lossy > radial wires is rather high. There's negligible current flowing in > them at distances greater than 1/4-wavelength at their own velocity. > The wires may just as well not be there. > . . . I'm afraid your oversimplified model of how radials work has once again led you astray. B, L, & E's measurements show the following: For an 88 degree high vertical, where n is the number of radials, the following fraction of the current at the center is flowing in the radial 1/4 wavelength (at a velocity factor of 0.2, the approximate VF in the radial's environment), from Fig. 42 of their paper: n Fraction 15 0.67 30 0.68 60 0.90 113 ~ 1.0 1/4 *free space* wavelength from the center: n Fraction 15 0.19 30 0.14 60 0.26 [This is a minimum; it rises then drops further out] 113 0.61 " " Note that the results are quite different when the radiator is only 22 degrees high (Fig. 43) -- the resonant effects apparent on the 60 and 113 radial measurements are absent, and the currents decay monotonically. There isn't nearly as much difference between 15 and 113 radials. But with 15 radials, the current 1/4 in-ground wavelength from the center is still about 67% of the current at the center. Again I see evidence that your analysis overlooks the interaction among radials. There's less interaction when there are only a few, but even with 15 your analysis has led you badly astray. And does it account for the considerable differences with different radiator heights? But I've pointed this out to you before yet you keep promoting this myth, so I guess you just don't want to be confused by the facts. > If B. L & E, made any errors, they made sure they erred on the safe > side regarding numbers. One of their key results is that ". . .the ground system consisting of only 15 radial wires need not be more than 0.1 [free space] wave length long, while the system consisting of 113 radials is still effective out to 0.5 [free space] wave length." Their results agree reasonably well with NEC-4 modeling. But I'm sure glad we've got you to set us straight about how well they did and how they could have improved their methods. You've surely got a clearer perspective, not having been prejudiced by actually reading their paper. Oops, here I am nitpicking again -- pointing out that .67 doesn't equal zero. Roy Lewallen, W7EL Certified Reg's Old Wife and Nit-Picker Article: 214432 of rec.radio.amateur.antenna From: ml Subject: re ian/Re: rich and Cecil momentum"Sloshing" EM Energy References: <42b337fc$1_1@spool9-west.superfeed.net> <18548-42B486DF-562@storefull-3256.bay.webtv.net> <1119188334.322677.10230@g49g2000cwa.googlegroups.com> <42bb6e3c$1_2@spool9-west.superfeed.net> <0fwn6EIGQRvCFAsv@ifwtech.co.uk> Message-ID: Date: Sat, 25 Jun 2005 10:10:51 GMT thanks for responding Ian: No doubt your correct about alot, and clasically speaking i wouldn't argue, however 2 points firstly my comparsion to einstein wasn't regarding myself i was making a joke that my 'theories /ideas' are often thought of as crazy but who knows regarding your being so firm saying that rf is typically just conventional physics, I dunno.. who says it's confirmed to our space?? we are only just begining to see the possibilities that things in our deminsion/ or time "e space" do in fact have relationships with 'other ' things, some of which might be having effects out of phase, 'time' or having somthing corresponding in another dimension so to speak (for example) it's not unfathomable to think that the sum of our current knowledge might no be infinate, perhaps we've simply failed to measure ? who knows what tomorrows proved new theories will bring? already here waves(rf) conventional were compared to photonic 'energy'(now thats something few can understand alone) and those photos do some really strange things w/regards to the above (even more strange) conventionally speaking your correct of course, but i always keep an open mind towards possibilities, and crazy theories, since rf is still such a not understood umm blackhole or i am just crazy yeah i am just a nutty non scientific type throwing wackey ideas i have into that round black hole hoping that i'll find the right sized peg(my best asylm analogy rich) not cause i want to be known, but it's just fun for me to ponder these things i've already learned alot from you ian thanks again rich and cecil thanks too m In article <0fwn6EIGQRvCFAsv@ifwtech.co.uk>, Ian White GM3SEK wrote: > ml wrote: > > > >then i think quantum things but even if i expertly understood all > >these parts, would I have the answers?? > > > You don't need to "think quantum things" about this problem. > > The discovery of quantum physics was that energy levels aren't > continuous. A "system" (whatever it may be) can only have certain levels > of energy - in-between energy levels are not allowed. To change between > energy level, the system must emit or absorb quanta of energy. > > Quantum energy E is related to frequency (f, Hz) by E = h*f, where h is > Planck's constant = 6.6 x 10^-34 Joule seconds. > > At 10MHz, the quantum energy is 0.000 000 000 000 000 000 000 000 0066 > joules. This is so small that - for all practical purposes - ANY energy > level is possible, and quantum effects at radio frequencies are so small > they are irrelevant. > > So quantum physics has just *confirmed* that, at radio frequencies, > classical EM physics is all you need to know. > > > >hey people thought people like einstein were nutz too and he was smart > > > The question is: are there any Einsteins here? > > Antennas and transmission lines are home territory for classical EM > physics, right in the middle of our map of existing knowledge. There are > still lots of interesting new things to be discovered there; but we know > in advance that they MUST join up with the existing map, because it > surrounds us on every side. > > Anybody who imagines he's an Einstein, exploring the outer boundaries... > is just plain lost. Article: 214433 of rec.radio.amateur.antenna From: "Asimov" Subject: Attic antenna: rotator upside-down work? Message-ID: Date: Friday, 24 Jun 2005 16:58:38 -500 References: "Bob B." bravely wrote to "All" (24 Jun 05 11:01:20) --- on the heady topic of "Attic antenna: rotator upside-down work?" BB> From: Bob B. BB> Xref: aeinews rec.radio.amateur.antenna:33120 BB> Hello... BB> Will an antenna rotator like a Radio Shack or Channel Master work if BB> hung upside-down from a roof beam, or should I try to come up with a BB> way to secure it to the attic floor? BB> I know rotators are designed to handle a certain weight, but I can't BB> guess at what they'd do with a "negative" weight... BB> The antenna I'm looking to rotate is a Channel Master 8-bay bowtie. BB> (CM4228) BB> Thanks, BB> -Bob- BB> N1GYL I think it might work because rotators are rated for a large wind load and hanging upside down doesn't even seem to come close to that. However, I'd call the mfr first to ask for their recommendation before doing it. I doubt any gears in the rotator depend on gravity to stay in place. OTOH do you think fix mounting the rotator shaft and having the antenna hanging off the mast fixture instead might work? A*s*i*m*o*v ... Thank Thor Friday Nears! Article: 214434 of rec.radio.amateur.antenna From: "Ed Price" References: <1119677469.165116.283260@o13g2000cwo.googlegroups.com> Subject: Re: 28mhz Message-ID: Date: Sat, 25 Jun 2005 05:13:18 -0700 "KI4CER" wrote in message news:1119677469.165116.283260@o13g2000cwo.googlegroups.com... >I have never seen a bigger bunch of crap than the crap posted on this > sight.I didn't see one call sign on the entire message post.The stuff > listed (and all it was was stuff)meant nothing to no one.sounds like to > me a bunch of wan a be's.Well don't let me catch you talking on 28mhz's > if you don't have a valid F.C.C. certificate of issue.I live to smight > the wicked truckerness on 28mhz.I run the full legal limit and our GOD > HOLY RILEY HOLLINGSWORTH hath given me the power to smight thy > truckerness and thy lewdness,and there ain't a damn thing you can do > about it.So I will look foward to warming up my equipment and standing > guard waiting for one peep from an un licenced asshole.Get the > message???????KI4CER > Thus all the non-hams monitoring this ham antenna group have been suitably warned. -- Ed WB6WSN El Cajon, CA USA Article: 214435 of rec.radio.amateur.antenna Date: Sat, 25 Jun 2005 09:02:04 -0500 From: Cecil Moore Subject: Re: re ian/Re: rich and Cecil momentum"Sloshing" EM Energy References: <42b337fc$1_1@spool9-west.superfeed.net> <18548-42B486DF-562@storefull-3256.bay.webtv.net> <1119188334.322677.10230@g49g2000cwa.googlegroups.com> <42bb6e3c$1_2@spool9-west.superfeed.net> <0fwn6EIGQRvCFAsv@ifwtech.co.uk> Message-ID: <42bd64d4$1_1@spool9-west.superfeed.net> ml wrote: > already here waves(rf) conventional were compared to photonic > 'energy' One conceptual mistake that a lot of people make concerns the roll of free electrons in a transmission line. It is the fields/photons that move at the speed of light, not the electrons. EM energy stored in excited free electrons is unstable and fleeting. The electron always gives up that extra energy very quickly in the form of photons which must necessarily travel at the speed of light and are incapable of some Old Wives' Tale "sloshing" response. Just because the electrons are capable of "sloshing" around doesn't mean that the EM energy can slosh around. The EM wave energy is not confined to the electrons, it exists ultimately in the fields/photons in the form of ExH wave energy/time moving at the speed of light. -- 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: 214436 of rec.radio.amateur.antenna From: "Fred W4JLE" References: <1119677469.165116.283260@o13g2000cwo.googlegroups.com> Subject: Re: 28mhz Date: Sat, 25 Jun 2005 10:20:26 -0400 Message-ID: I am curious as to why you would post such nonsense. You are simply inviting a contestant in the who has the largest member contest. The typical response will be something like "You (profanity omitted) hams ain't got (P.O.) Iz runin 10KW with a (P.O.) 92 pill Dave made and a balum to co-fazed... " Ad nasuium... What's the point? "KI4CER" wrote in message news:1119677469.165116.283260@o13g2000cwo.googlegroups.com... > I have never seen a bigger bunch of crap than the crap posted on this > sight.I didn't see one call sign on the entire message post.The stuff > listed (and all it was was stuff)meant nothing to no one.sounds like to > me a bunch of wan a be's.Well don't let me catch you talking on 28mhz's > if you don't have a valid F.C.C. certificate of issue.I live to smight > the wicked truckerness on 28mhz.I run the full legal limit and our GOD > HOLY RILEY HOLLINGSWORTH hath given me the power to smight thy > truckerness and thy lewdness,and there ain't a damn thing you can do > about it.So I will look foward to warming up my equipment and standing > guard waiting for one peep from an un licenced asshole.Get the > message???????KI4CER > Article: 214437 of rec.radio.amateur.antenna From: "RST Engineering" Subject: Re: 28mhz Date: Sat, 25 Jun 2005 08:23:04 -0700 Message-ID: <11bqtn2s9ioil61@corp.supernews.com> References: <1119677469.165116.283260@o13g2000cwo.googlegroups.com> Well, if you are waiting for a reply on this "sight" (sic) for some 28 millihertz discussion, you will be waiting a very long time. Jim "KI4CER" wrote in message news:1119677469.165116.283260@o13g2000cwo.googlegroups.com... >I have never seen a bigger bunch of crap than the crap posted on this > sight. Article: 214438 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: How to measure soil constants at HF Date: Sat, 25 Jun 2005 10:30:08 -0500 Message-ID: <17269-42BD7880-249@storefull-3254.bay.webtv.net> References: Reg, G4FGQ wrote: "Your ancient charts, which I think I have once seen but don`t now have access to, apply only to LF. Permittivity was ignored when they were calculated." True, they are not for HF. My edition was reprinted by the Seabrooke Printing Company, Inc. and covers the range ftom 540 KHz to 1600 KHz. Dielectric constant (permittivity) is assumed to be 15 in all cases. The reason there are graphs for frequency segments such as 1560 kc to 1640 kc is that loss increases with frequency. Skin effect is an important faxtor. The higher the frequency, the less it penetrates the earth, so the crust carrying the r-f is thinner. The decline of field intensity versus distance from the transmitter is steeper at HF. My set of curves has a page which gives the formulas used to construct "surface wave field intensity versus numerical distance over plane earth". It has separate sets of formulas for vertical and horizontal polarizations. Curves in the book are for vertical polarization, the only thing of interest to a broadcaster. One option would be to construct your own set of curves. Another would be to find some curves which have already been constructed. I don`t know of any but expect that they exist. Best regards, Richard Harrison, KB5WZI Article: 214439 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: Using the matchbox Date: Sat, 25 Jun 2005 17:01:21 +0000 (UTC) Message-ID: References: <1119554991.240126.47990@g49g2000cwa.googlegroups.com> <1119618054.991193.201730@z14g2000cwz.googlegroups.com> <42bc1ddf$1_2@spool9-west.superfeed.net> > > Nothing has changed since Oliver Heaviside, 1875 - 1925. > > > > If anybody mentions G5RV I shall cry. > > ---- > > Reg, G4FGQ > > > > G5RV > 73, > Tom Donaly, KA6RUH =============================== Bwwaaaaaaaaaaaaaaa Thanks Tom, I feel better now. --- Reg. Article: 214440 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Re: How to measure soil constants at HF Date: Sat, 25 Jun 2005 18:34:17 +0000 (UTC) Message-ID: References: <11bhb2khc92phf0@corp.supernews.com> <20290-42B8E899-1291@storefull-3255.bay.webtv.net> <11bq9oriipqncd8@corp.supernews.com> Roy, surely you realise that all depends on soil conductivity and permittivity which B, L & E forgot to determine before leaving the site. 30 years previously, around 1905, Sommerfeld (and others) had produced a significant report showing the importance of ground characteristics on radiation and propagation at LF and below. Which B, L, & E ought to have been aware of if they had known what they were about. You should concentrate your thoughts on HF and above, not on LF and VLF distractions. Different characteristics prevail at HF at which frequencies amateurs are most concerned. ---- Reg Article: 214441 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: How to measure soil constants at HF Date: Sat, 25 Jun 2005 12:18:23 -0700 Message-ID: <11brbg08ffamv2b@corp.supernews.com> References: <11bhb2khc92phf0@corp.supernews.com> <20290-42B8E899-1291@storefull-3255.bay.webtv.net> <11bq9oriipqncd8@corp.supernews.com> Reg Edwards wrote: > Roy, surely you realise that all depends on soil conductivity and > permittivity which B, L & E forgot to determine before leaving the > site. It just isn't sinking in, is it? It depends on the conductivity and permittivity to a skin depth or more, which was impossible for them to determine. A surface measurement wouldn't have provided the necessary information. Measurement of ground wave attenuation to another location would have included ground with a variety of possible characteristics different from those in the immediate vicinity. > 30 years previously, around 1905, Sommerfeld (and others) had produced > a significant report showing the importance of ground characteristics > on radiation and propagation at LF and below. Which B, L, & E ought > to have been aware of if they had known what they were about. I'm sure they were. But the paper has nothing to do with propagation. What makes you think it does? They certainly did know about the effect of conductivity. In a theoretical analysis at the beginning of their paper they calculated expected radial ground currents for several different ground conductivities, and explain how current is distributed in the ground with conductivity being a factor. The radial ground current analysis was later found to be in error(*), but it's still considerably closer than the results I've seen from your analysis and program. > You should concentrate your thoughts on HF and above, not on LF and > VLF distractions. Different characteristics prevail at HF at which > frequencies amateurs are most concerned. That's a bizarre admonition from someone constantly harping about how many radials American AM broadcasters use. I am indeed most interested in HF, where skin depth is on the order of 12 feet for average soil, and measurement of surface conductivity and permittivity is pretty useless. Incidentally, since you haven't read their paper, you probably don't know that the BL & E measurements were done at 3 MHz, which is HF. (*) To my knowledge, no one has developed a method of calculating radial currents or ground system losses with even approximate accuracy other than with numerical analysis such as used by NEC-4. Many years ago I spent a couple of years of spare time in a technical library looking for just such an analysis without success. Reg's method is delightfully simple but gives results which are very wrong. Roy Lewallen, W7EL Article: 214442 of rec.radio.amateur.antenna Date: Sat, 25 Jun 2005 14:21:19 -0500 From: Cecil Moore Subject: Re: re ian/Re: rich and Cecil momentum"Sloshing" EM Energy References: <42b337fc$1_1@spool9-west.superfeed.net> <18548-42B486DF-562@storefull-3256.bay.webtv.net> <1119188334.322677.10230@g49g2000cwa.googlegroups.com> <42bb6e3c$1_2@spool9-west.superfeed.net> <0fwn6EIGQRvCFAsv@ifwtech.co.uk> <42bd64d4$1_1@spool9-west.superfeed.net> Message-ID: <42bdafa9$1_2@spool9-west.superfeed.net> Richard Clark wrote: > On Sat, 25 Jun 2005 09:02:04 -0500, Cecil Moore > wrote: > >>One conceptual mistake that a lot of people make concerns >>the roll of free electrons in a transmission line. > > Concepts indeed. Rolling free electrons. > How did Planck miss this one? I can visualize marbles cascading down > a quantum stairwell though. ;-) Once again, the Netscape spellchecker fails to catch the typo. I have an inherited palsy as did my father and as does my sister. My sister has had electrodes implanted in her brain to try to control it but she, like I, still has a lot of trouble typing. It takes me five times as long to compose an acceptable posting as the average person because of all the double and triple entries. I sincerely appologize that my physical handicap has exposed your psychological tendency to make fun of the misfortunes of others. -- 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: 214443 of rec.radio.amateur.antenna Date: Sat, 25 Jun 2005 14:22:38 -0500 From: Cecil Moore Subject: Re: Using the matchbox References: <1119554991.240126.47990@g49g2000cwa.googlegroups.com> <1119618054.991193.201730@z14g2000cwz.googlegroups.com> <42bc1ddf$1_2@spool9-west.superfeed.net> Message-ID: <42bdaff8$1_2@spool9-west.superfeed.net> Reg Edwards wrote: >>>If anybody mentions G5RV I shall cry. >>G5RV > Bwwaaaaaaaaaaaaaaa > Thanks Tom, I feel better now. Reg, you know you mentioned G5RV first. :-) -- 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: 214444 of rec.radio.amateur.antenna From: "John Smith" References: <1119677469.165116.283260@o13g2000cwo.googlegroups.com> Subject: Re: 28mhz Message-ID: Date: Sat, 25 Jun 2005 13:09:23 -0700 Yes, that is a really good rant... I can almost imagine the truckers upgrading linears now... I hope that was your true intent--it is hard to imagine anyone would think it would inspire different... John "KI4CER" wrote in message news:1119677469.165116.283260@o13g2000cwo.googlegroups.com... >I have never seen a bigger bunch of crap than the crap posted on this > sight.I didn't see one call sign on the entire message post.The stuff > listed (and all it was was stuff)meant nothing to no one.sounds like > to > me a bunch of wan a be's.Well don't let me catch you talking on > 28mhz's > if you don't have a valid F.C.C. certificate of issue.I live to smight > the wicked truckerness on 28mhz.I run the full legal limit and our GOD > HOLY RILEY HOLLINGSWORTH hath given me the power to smight thy > truckerness and thy lewdness,and there ain't a damn thing you can do > about it.So I will look foward to warming up my equipment and standing > guard waiting for one peep from an un licenced asshole.Get the > message???????KI4CER > Article: 214445 of rec.radio.amateur.antenna Date: Sat, 25 Jun 2005 15:35:53 -0500 From: Cecil Moore Subject: Re: re ian/Re: rich and Cecil momentum"Sloshing" EM Energy References: <42b337fc$1_1@spool9-west.superfeed.net> <18548-42B486DF-562@storefull-3256.bay.webtv.net> <1119188334.322677.10230@g49g2000cwa.googlegroups.com> <42bb6e3c$1_2@spool9-west.superfeed.net> <0fwn6EIGQRvCFAsv@ifwtech.co.uk> <42bd64d4$1_1@spool9-west.superfeed.net> <42bdafa9$1_2@spool9-west.superfeed.net> Message-ID: <42bdc121$1_2@spool9-west.superfeed.net> Richard Clark wrote: > On Sat, 25 Jun 2005 14:21:19 -0500, Cecil Moore > wrote: > >>I sincerely appologize that my physical handicap has exposed your >>psychological tendency to make fun of the misfortunes of others. > > No, yours is not an appology - as you well know. Your hand at irony > is firmly intact as all may notice in this cheap play with the > sympathy card. Care to see a picture of my sister's shaved head after surgery? -- 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: 214446 of rec.radio.amateur.antenna From: "Richard W. Solomon, W1KSZ" Subject: Re: Correct cable for 920Mhz Mobile, Yagi Message-ID: References: Date: Sat, 25 Jun 2005 21:20:35 GMT RG-58 ?? You might as well bury the antenna in the ground !! That is the worst stuff you can use. First, How long a run do you need ? Second, What is the connector required on each end ? 73, Dick, W1KSZ On Sat, 25 Jun 2005 11:19:42 +0200, Mark wrote: >Please could somebody tell me the best cable (compromise between cost >and loss) for use with an external Yagi antenna connected to a mobile >phone. I live in a Very poor reception area, and I need to fit an >external antenna. I have found somewhere that sells 10 element Yagi's, >and I can mount the thing as high as need be, but I read somewhere >that the longer the connecting cable, can negate the benefits of long >mounting poles. I have freinds in the surrounding area that have the >same problem, so I could do with a "rule of thumb" that I can use for >fitting these things. The shop where I got the antenna from is >offering me RG58 cable for this purpose, which is cheap enough, but is >it the best compromise for what I am trying to achieve? Your >assistance would be most welcome. >Mark Article: 214447 of rec.radio.amateur.antenna From: "Hal Rosser" References: Subject: Re: Correct cable for 920Mhz Mobile, Yagi Message-ID: Date: Sat, 25 Jun 2005 17:40:50 -0400 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 "Mark" wrote in message news:et7qb1la2lr29hpnu0741kv79ii9ecj2c8@4ax.com... > Please could somebody tell me the best cable (compromise between cost > and loss) for use with an external Yagi antenna connected to a mobile > phone. I live in a Very poor reception area, and I need to fit an > external antenna. I have found somewhere that sells 10 element Yagi's, > and I can mount the thing as high as need be, but I read somewhere > that the longer the connecting cable, can negate the benefits of long > mounting poles. I have freinds in the surrounding area that have the > same problem, so I could do with a "rule of thumb" that I can use for > fitting these things. The shop where I got the antenna from is > offering me RG58 cable for this purpose, which is cheap enough, but is > it the best compromise for what I am trying to achieve? Your > assistance would be most welcome. > Mark Article: 214448 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: How to measure soil constants at HF Date: Sat, 25 Jun 2005 16:46:39 -0500 Message-ID: <20797-42BDD0BF-27@storefull-3251.bay.webtv.net> References: <17269-42BD7880-249@storefull-3254.bay.webtv.net> I wrote: "Another (option) would be to find some curves which have already been constructed." Found some curves in Pete Saveskie`s "Radio Propagation Handbook" on pages 15, 17, and 19. They are from CCIR and may be available from them. They are for field strengths over sea water, good earth, and poor earth at 16 frequencies from 100 KHz to 10 MHZ. Best regards, Richard Harrison, KB5WZI Article: 214449 of rec.radio.amateur.antenna From: Owen Subject: Re: offset diople antenna References: <_K6dncKmBLpD0SHfRVn-uQ@rogers.com> <11bpan6pobgvq5c@corp.supernews.com> Message-ID: Date: Sat, 25 Jun 2005 22:07:48 GMT Roy Lewallen wrote: > Chuck Olson wrote: > >> >> Hi, Larry, >> >> An off-center fed antenna doesn't necessarily produce unbalanced feeder >> currents - - > > > I'm sorry to say, it does. There's coupling from the feedline to each > side of the antenna, and unlike a symmetrical dipole with feedline at > right angles, the coupling from each side is unequal. This results in > unbalanced feeder currents. If the feedline is twinlead or open wire > line, this shows up as unequal currents on the two conductors. On coax > it manifests itself as current on the outside of the shield. In both > cases, the result is the same -- feedline radiation. > > This can be shown quite dramatically by simple modeling. I've also seen > it myself by direct measurement(*). A current balun (NOT voltage balun) > at the feedpoint will reduce the conducted common mode current just as > it will with a dipole, but you still have to deal with common mode > current due to coupling. Depending on the frequency and the feedline > length and orientation, you might get lucky and not have too much > feedline current. On the other hand, it can be bad enough to aggravate > RFI problems if the feedline is routed near power or telephone lines, or > cause trouble with your rig or shack accessories. > > > just a different feeding impedance level, which he will no > >> doubt take care of with a tuner or a 4:1 ratio in the balun if single >> band >> use is all he wants and he can find the right spot for the feeder. Of >> course >> the balun takes care of any unbalance that might be due to the feeder >> not making a 90 degree angle with the antenna. There's nothing wrong >> with his idea. > > > See above comments. Routing the feeder at right angles to the antenna > doesn't eliminate current due to mutual coupling, and neither does a > feedpoint balun. > Roy, doesn't this suggest that there is benefit in twisting an open wire feedline to attempt to expose each conductor to similar coupling to the external fields. Clearly the benefit will be better for a higher twist rate. Whilst achieving sufficient twist rate with a wide air-spaced line may be impractical, it is probably quite realisable with ladder line (notwithstanding the downsides of ladder line). I suspect there is not much one could do to minimise the effects of current on a coax shield other than placement of ferrite suppression sleeves or loops in the coax at several places on the feedline to spoil resonances in much the same way as one would try to prevent parasitic excitation of a guy wire by breaking into non-resonant lengths with insulators. Owen Article: 214450 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: Using the matchbox Message-ID: <2rlrb1ljquvan08cmimqi6p33g87a7fuec@4ax.com> References: <1119554991.240126.47990@g49g2000cwa.googlegroups.com> Date: Sat, 25 Jun 2005 22:15:32 GMT On Fri, 24 Jun 2005 23:40:45 -0400, Buck wrote: >On Thu, 23 Jun 2005 15:06:33 -0700, Wes Stewart >wrote: > >>On 23 Jun 2005 12:29:51 -0700, "Brian Kelly" wrote: > >>>Inductors are lossy. Capacitors are not. Use the tuner settings which >>>provide a 2:1 VSWR match or better with the least possible amount of >>>inductance. In other words use the least amount of inductance you can >>>get away with. >> > >>First all should note that this is a pi-network. Suggestions to use >>an MFJ (tee-network) tuning procedure are wrong. >> >>Here is a random example made up on the spur of the moment. >> >>Assume the load is 20 +j50 @ 14 MHz. SWR = 5.2 >> >>Also assume that the tuning capacitor(s) Q = 500 and the inductor Q = >>200, both typical values. >> >>A nearly optimum solution, from a match and loss standpoint is: >> >>Cin = 140.3 pF, L = .958 uH, Cout = 333.6 pF. >> >>The input z = 49.69 +j0.03 or SWR = 1.006 , Loss = 0.09 dB. >> >>Now, let's force the inductance to a lower value. >> >>Cin = 422 pF, L = 0.67 uH, Cout = 471.3 pF. >> >>The input Z = 49.6 -j0.04 or SWR = 1.008 but the loss = 0.18 dB. >> >>The loss doubled when the inductance was lowered. >> >>All of this is easily calculated using a free tool: XLZIZL.xls. >> > >Does anyone know what kind of network is in the TenTec 247? > >I have one and noticed it will tune most bands with three different >inductance settings. There might be some info at the vintage ten-tec site, http://www.qsl.net/tentec/ bob k5qwg Article: 214451 of rec.radio.amateur.antenna From: Roy Lewallen Subject: Re: offset diople antenna Date: Sat, 25 Jun 2005 15:47:30 -0700 Message-ID: <11brno2m7vmjg99@corp.supernews.com> References: <_K6dncKmBLpD0SHfRVn-uQ@rogers.com> <11bpan6pobgvq5c@corp.supernews.com> Owen wrote: > Roy Lewallen wrote: >>. . . >> See above comments. Routing the feeder at right angles to the antenna >> doesn't eliminate current due to mutual coupling, and neither does a >> feedpoint balun. >> > > Roy, doesn't this suggest that there is benefit in twisting an open wire > feedline to attempt to expose each conductor to similar coupling to the > external fields. Clearly the benefit will be better for a higher twist > rate. Whilst achieving sufficient twist rate with a wide air-spaced line > may be impractical, it is probably quite realisable with ladder line > (notwithstanding the downsides of ladder line). No. The problem isn't that the coupling is different to each conductor of the transmission line, it's that the coupling is different from the transmission line to each side of the antenna. Twisting the line won't change the coupling of this common mode current by any appreciable amount. Unfortunately. > I suspect there is not much one could do to minimise the effects of > current on a coax shield other than placement of ferrite suppression > sleeves or loops in the coax at several places on the feedline to spoil > resonances in much the same way as one would try to prevent parasitic > excitation of a guy wire by breaking into non-resonant lengths with > insulators. The problem is exactly the same for coax and for two-wire line, and the solution is the same for both -- common mode chokes (current baluns) spaced about a quarter wavelength apart to break up resonances. In practice, implementation is usually easier with coax. Roy Lewallen, W7EL Article: 214452 of rec.radio.amateur.antenna From: "John Smith" Subject: I was requested to post the following... Message-ID: Date: Sat, 25 Jun 2005 14:28:20 -0700 The email requesting me to make this post follows: The following post was not posted by me. the person who claims to be me is a very childish individual that has never left their mothers apron. Please post this in the USENET groups, as I am not a member. If any of you know how to trace this post back to the source please email me at kf4vgx@hotmail.com 73 John > I'm just a lonely ham. Nobody wants to play radio > with me. Please e-mail me. I'm tired of emailing > myself, it's no fun anymore. > > Johnny Williams > kf4vgx@sc.rr.com > Article: 214453 of rec.radio.amateur.antenna From: "John Smith" Subject: Post anonymously Message-ID: Date: Sat, 25 Jun 2005 17:37:26 -0700 I am sure that everyone here has noticed there is much too much attention paid to where posts originate from. And, there are childish personalities which look up where you are posting from--some with malicious intent... This URL will provide you with a means to be anonymous: http://www.antifirewall.com/news.htm This should allow everyone to put a stop to this bad behavior. John Article: 214454 of rec.radio.amateur.antenna From: "John Smith" References: <1119747738.926814.292740@g47g2000cwa.googlegroups.com> Subject: Re: Post anonymously Message-ID: <_enve.47$dt1.11443224@news.sisna.com> Date: Sat, 25 Jun 2005 18:09:15 -0700 bb: Well, antifirewall has a trial period... But, it should help you become familiar with the method to be able to set this up using other methods which are free... John "bb" wrote in message news:1119747738.926814.292740@g47g2000cwa.googlegroups.com... > > > John Smith wrote: >> I am sure that everyone here has noticed there is much too much >> attention paid to where posts originate from. And, there are >> childish >> personalities which look up where you are posting from--some with >> malicious intent... >> >> This URL will provide you with a means to be anonymous: >> http://www.antifirewall.com/news.htm >> >> This should allow everyone to put a stop to this bad behavior. >> >> John > > Yeh, I really don't like Robeson posting snippets of my address or > talking about my family. > Article: 214455 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: momentum"Sloshing" EM Energy Date: Sat, 25 Jun 2005 21:53:00 -0500 Message-ID: <8199-42BE188C-328@storefull-3257.bay.webtv.net> References: <42bb6e3c$1_2@spool9-west.superfeed.net> Look at the title of this thread. Why slosh? Transmission lines are used to convey energy, and at high frequencies they serve as resonant circuits, measuring devices, and impedance matching sections. Viltage and current at any point on a transmission line is expressed as the sum of the voltages and currents of two waves, one traveking forward toward the load (the incident wave) and one reflected from the load (the reflected or reverse wave). The reflected wave consists of energy from the wave traveling toward the load which is rejected by the load becausse the voltage to current ratio does not fit the only voltage to current ratio the load can accept, its impedance, perhaps a complex value. All energy in the wave traveling toward the load and all energy traveling away from the load (the opposite travel direction) must conform to the absolute value of the line`s characteristic impedance (Zo). Phase of the reflected current traveling back toward the generator is given a negative sign because the reflected wave is traveling in the reverse direction from the forward wave which travels toward the load. (See page 86 in the 1955 edition of Terman. Phase of the reflected current traveling toward the generator is everywhere proportional but out of phase with reflected voltage. The reflected voltage to current ratio is: -Zo. Actual voltage across the load is the sum of the incident and reflected voltages. Actual current through the load is the sum of the incident and reflected currents. The vector ratio of load voltage to load current must equal the load impedance which may be a complex value. The vector ratio of incident voltage to treflected voltage at the load is called the reflection coefficient of the load. It may be obtained >from forward and reverse powers at the load. I have a special slide rule given me by the Bird wattmeter people to convert wattmeter forward and reverse indications into a reflection coefficient or an SWR. The transmission line and its load completely control the volts and amps everywhere in the system driven by a certain generator. There are no renegade volts and amps sloshing around. The idea is preposterous. Best regards, Richard Harrison, KB5WZI Article: 214456 of rec.radio.amateur.antenna From: "Charlie" Subject: AD5TH Tower Project Completed - Pics Online Date: Sun, 26 Jun 2005 00:04:05 -0500 Message-ID: <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: 214457 of rec.radio.amateur.antenna Message-ID: <313030303837383542BEA00A47@zetnet.co.uk> Date: Sun, 26 Jun 2005 12:31:06 +0100 From: Dave Piggin Subject: Solarcon A99 Hi All, Anyone got a link to a schematic for the A99. I'm blowed if I can find how the wire terminates into the top collar. What I did find was a solder blob on the collar, thinking Aha thats where the wire termminates, but NO. Any idea's appreciated. TIA 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 Dont. Article: 214458 of rec.radio.amateur.antenna From: "Joe S." Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Sun, 26 Jun 2005 06:47:14 -0500 Message-ID: References: <11bsdqpir7o54fa@news.supernews.com> "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 > > > > > > Do I understand that the guy wires terminate to trees? Is that a permanent arrangement? -- ----- Joe S. Article: 214459 of rec.radio.amateur.antenna Date: Sun, 26 Jun 2005 07:26:45 -0500 From: Cecil Moore Subject: Re: momentum"Sloshing" EM Energy References: <42bb6e3c$1_2@spool9-west.superfeed.net> <8199-42BE188C-328@storefull-3257.bay.webtv.net> Message-ID: <42be9ffe$1_2@spool9-west.superfeed.net> Richard Harrison wrote: > There are no > renegade volts and amps sloshing around. The idea is preposterous. Thanks for all your statements of the laws of physics embodied in the wave reflection model. -- 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: 214460 of rec.radio.amateur.antenna From: Walt Davidson Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Sun, 26 Jun 2005 13:29:45 +0100 Message-ID: <187tb1leujpn0c0ossfg1u9v9c46c21jgp@4ax.com> References: <11bsdqpir7o54fa@news.supernews.com> On Sun, 26 Jun 2005 06:47:14 -0500, "Joe S." wrote: >Do I understand that the guy wires terminate to trees? Is that a permanent >arrangement? Boy, I bet that 21 ft "stub mast" will whip around some when the wind gets up! Only the rotator is supporting it. -- Walt Davidson Email: g3nyy @despammed.com Article: 214461 of rec.radio.amateur.antenna Date: Sun, 26 Jun 2005 07:48:55 -0500 From: Cecil Moore Subject: Re: re ian/Re: rich and Cecil momentum"Sloshing" EM Energy References: <42b337fc$1_1@spool9-west.superfeed.net> <18548-42B486DF-562@storefull-3256.bay.webtv.net> <1119188334.322677.10230@g49g2000cwa.googlegroups.com> <42bb6e3c$1_2@spool9-west.superfeed.net> <0fwn6EIGQRvCFAsv@ifwtech.co.uk> <42bd64d4$1_1@spool9-west.superfeed.net> <42bdafa9$1_2@spool9-west.superfeed.net> Message-ID: <42bea52f$1_1@spool9-west.superfeed.net> Richard Clark wrote: > No, yours is not an appology - as you well know. Your hand at irony > is firmly intact as all may notice in this cheap play with the > sympathy card. The devil made me do it, Richard. I just couldn't resist a cheap shot at the resident cheap shot artist. :-) -- 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: 214462 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: References: <11bsdqpir7o54fa@news.supernews.com> Date: Sun, 26 Jun 2005 12:57:12 GMT On Sun, 26 Jun 2005 06:47:14 -0500, "Joe S." wrote: > > >"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 >> >> >> >> >> >> > >Do I understand that the guy wires terminate to trees? Is that a permanent >arrangement? Also, do the steel bands allow for the expansion of the tree trunk? Them things do grow... bob k5qwg Article: 214463 of rec.radio.amateur.antenna From: "Reg Edwards" Subject: Choke baluns again Date: Sun, 26 Jun 2005 13:37:46 +0000 (UTC) Message-ID: A choke balun is what is inserted between the transmitter end of the antenna feedline and the transmitte tuner. Or it can be inserted at the antenna end of the line. Questions : How effective is it? To what extent can the percentage unbalance current on the feedline be expected to be reduced? Has anybody ever measured it before and after insertion? ---- Reg. Article: 214464 of rec.radio.amateur.antenna From: W9DMK (Robert Lay) Subject: Re: momentum"Sloshing" EM Energy Date: Sun, 26 Jun 2005 13:53:35 GMT Message-ID: <42beb22b.4515032@news.crosslink.net> References: <42bb6e3c$1_2@spool9-west.superfeed.net> <8199-42BE188C-328@storefull-3257.bay.webtv.net> On Sat, 25 Jun 2005 21:53:00 -0500, richardharrison@webtv.net (Richard Harrison) wrote: >The reflected wave consists of energy from the wave traveling toward the >load which is rejected by the load becausse the voltage to current ratio >does not fit the only voltage to current ratio the load can accept, its >impedance, perhaps a complex value. Dear Richard, Aside from some easily correctable typos, your posting is very readable and cogent. The above paragraph, however, has a rather difficult to understand ending, and I'm hoping you will review it and provide more readable wording. Bob, W9DMK, Dahlgren, VA Replace "nobody" with my callsign for e-mail http://www.qsl.net/w9dmk http://zaffora/f2o.org/W9DMK/W9dmk.html Article: 214465 of rec.radio.amateur.antenna From: "John Smith" References: Subject: Re: Choke baluns again Message-ID: Date: Sun, 26 Jun 2005 08:40:29 -0700 ... I should have pointed out, always, the balun has been inserted at the antenna, and never at the transmitter end of the coax in my previous post... John "John Smith" wrote in message news:ACzve.9$Dl.332926@news.sisna.com... > Reg: > > I can comment on my recent experiments with a half-wave vertical on > 10-11 meters. > > A current balun (or ferrite beads on the coax) greatly reduce feedline > radiation--seems to have an overall beneficial effects on the antennas > radiation pattern--and seems to "stabilize" the pruning/tuning of the > antenna (things begin behaving in a linear and logical way.) > > Mind you, the above is only deduced/measured with a FSM, SWR bridge > (of the type which does NOT work for real measurement of swr but > rather transmitter loading) and observed/known signals from other > stations and the reports given back on my signal from these stations. > > While this may be viewed as "crude" by some--it is real world in that > the effects as least "seem" real. > > Or, the short form of all this is, "The Current Balun is my friend!" > > John > > "Reg Edwards" wrote in message > news:d9mb3a$de3$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com... >>A choke balun is what is inserted between the transmitter end of the >> antenna feedline and the transmitte tuner. Or it can be inserted at >> the antenna end of the line. >> >> Questions : How effective is it? To what extent can the percentage >> unbalance current on the feedline be expected to be reduced? Has >> anybody ever measured it before and after insertion? >> ---- >> Reg. >> >> > Article: 214466 of rec.radio.amateur.antenna From: "John Smith" References: Subject: Re: Choke baluns again Message-ID: Date: Sun, 26 Jun 2005 08:13:34 -0700 Reg: I can comment on my recent experiments with a half-wave vertical on 10-11 meters. A current balun (or ferrite beads on the coax) greatly reduce feedline radiation--seems to have an overall beneficial effects on the antennas radiation pattern--and seems to "stabilize" the pruning/tuning of the antenna (things begin behaving in a linear and logical way.) Mind you, the above is only deduced/measured with a FSM, SWR bridge (of the type which does NOT work for real measurement of swr but rather transmitter loading) and observed/known signals from other stations and the reports given back on my signal from these stations. While this may be viewed as "crude" by some--it is real world in that the effects as least "seem" real. Or, the short form of all this is, "The Current Balun is my friend!" John "Reg Edwards" wrote in message news:d9mb3a$de3$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com... >A choke balun is what is inserted between the transmitter end of the > antenna feedline and the transmitte tuner. Or it can be inserted at > the antenna end of the line. > > Questions : How effective is it? To what extent can the percentage > unbalance current on the feedline be expected to be reduced? Has > anybody ever measured it before and after insertion? > ---- > Reg. > > Article: 214467 of rec.radio.amateur.antenna From: "John Smith" References: Subject: Re: Choke baluns again Message-ID: Date: Sun, 26 Jun 2005 09:04:24 -0700 ... yes, I am known to reply to my own posts--far too often... >From all the current baluns I have tried, and I have tried every type I could find, this choke/balun design is my favorite and seems to have the lowest insertion loss of all and seems to exhibit excellent qualities of the type desired: http://home.datacomm.ch/hb9abx/pactor-e-choke.htm John "John Smith" wrote in message news:U%zve.10$R41.415864@news.sisna.com... > ... I should have pointed out, always, the balun has been inserted at > the antenna, and never at the transmitter end of the coax in my > previous post... > > John > > "John Smith" wrote in message > news:ACzve.9$Dl.332926@news.sisna.com... >> Reg: >> >> I can comment on my recent experiments with a half-wave vertical on >> 10-11 meters. >> >> A current balun (or ferrite beads on the coax) greatly reduce >> feedline radiation--seems to have an overall beneficial effects on >> the antennas radiation pattern--and seems to "stabilize" the >> pruning/tuning of the antenna (things begin behaving in a linear and >> logical way.) >> >> Mind you, the above is only deduced/measured with a FSM, SWR bridge >> (of the type which does NOT work for real measurement of swr but >> rather transmitter loading) and observed/known signals from other >> stations and the reports given back on my signal from these stations. >> >> While this may be viewed as "crude" by some--it is real world in that >> the effects as least "seem" real. >> >> Or, the short form of all this is, "The Current Balun is my friend!" >> >> John >> >> "Reg Edwards" wrote in message >> news:d9mb3a$de3$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com... >>>A choke balun is what is inserted between the transmitter end of the >>> antenna feedline and the transmitte tuner. Or it can be inserted at >>> the antenna end of the line. >>> >>> Questions : How effective is it? To what extent can the percentage >>> unbalance current on the feedline be expected to be reduced? Has >>> anybody ever measured it before and after insertion? >>> ---- >>> Reg. >>> >>> >> > Article: 214468 of rec.radio.amateur.antenna From: "John Smith" References: Subject: Re: A Single-Core 4:1 Current Balun Message-ID: Date: Sun, 26 Jun 2005 09:49:33 -0700 A very interesting analysis of this design can be found at: http://www.w8ji.com/balun_single_core_41_analysis.htm ... for those who have not yet seen it. John "Chris Trask" wrote in message news:eTdue.7890$jX6.6278@newsread2.news.pas.earthlink.net... > In recent days on the QRP-L mailing list, the following remarks > were > made by Tom Rauch, W8JI regarding the design of 4:1 current baluns: > > "...it is impossible to build a 4:1 ratio current balun that > uses two 1:1 baluns on a single core." > > and: > > "It's well established any balun made up of series / parallel > transmission lines requires different voltages from the start > to finish of each transmission line. " > > I have devised and modeled a 4:1 current balun using two 1:1 baluns on > a > single core, and have tested a fully functional prototype. The design > can > be built without any core, if so desired. The full disclosure of this > design with all theory, references, and test results can be obtained > from my > web page at: > > http://www.home.earthlink.net/~christrask/Trask4to1Balun.pdf > > The design proves beyond all reasonable doubt that the above > statements to > the contrary are, to put it mildly, gravely in error. > > 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 > > > > > > Article: 214469 of rec.radio.amateur.antenna From: "Hal Rosser" References: Subject: Re: Choke baluns again Message-ID: Date: Sun, 26 Jun 2005 14:19:30 -0400 The only thing I have against them (current baluns) is They are heavy. and cause the antenna to droop lowering the height of the feedpoint. Which is a good reason to put the balun near the radio and use balanced feedline from there to the antenna my 3.5 cents "John Smith" wrote in message news:SmAve.12$p6.310300@news.sisna.com... > ... yes, I am known to reply to my own posts--far too often... > > From all the current baluns I have tried, and I have tried every type I > could find, this choke/balun design is my favorite and seems to have the > lowest insertion loss of all and seems to exhibit excellent qualities of > the type desired: > http://home.datacomm.ch/hb9abx/pactor-e-choke.htm > > John > > "John Smith" wrote in message > news:U%zve.10$R41.415864@news.sisna.com... > > ... I should have pointed out, always, the balun has been inserted at > > the antenna, and never at the transmitter end of the coax in my > > previous post... > > > > John > > > > "John Smith" wrote in message > > news:ACzve.9$Dl.332926@news.sisna.com... > >> Reg: > >> > >> I can comment on my recent experiments with a half-wave vertical on > >> 10-11 meters. > >> > >> A current balun (or ferrite beads on the coax) greatly reduce > >> feedline radiation--seems to have an overall beneficial effects on > >> the antennas radiation pattern--and seems to "stabilize" the > >> pruning/tuning of the antenna (things begin behaving in a linear and > >> logical way.) > >> > >> Mind you, the above is only deduced/measured with a FSM, SWR bridge > >> (of the type which does NOT work for real measurement of swr but > >> rather transmitter loading) and observed/known signals from other > >> stations and the reports given back on my signal from these stations. > >> > >> While this may be viewed as "crude" by some--it is real world in that > >> the effects as least "seem" real. > >> > >> Or, the short form of all this is, "The Current Balun is my friend!" > >> > >> John > >> > >> "Reg Edwards" wrote in message > >> news:d9mb3a$de3$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com... > >>>A choke balun is what is inserted between the transmitter end of the > >>> antenna feedline and the transmitte tuner. Or it can be inserted at > >>> the antenna end of the line. > >>> > >>> Questions : How effective is it? To what extent can the percentage > >>> unbalance current on the feedline be expected to be reduced? Has > >>> anybody ever measured it before and after insertion? > >>> ---- > >>> Reg. > >>> > >>> > >> > > > Article: 214470 of rec.radio.amateur.antenna Date: Sun, 26 Jun 2005 14:28:23 -0500 From: Cecil Moore Subject: Re: Choke baluns again References: <1rttb1po7mrncf72v5v2kf8f8pmco6b5c6@4ax.com> Message-ID: <42bf02d0$1_1@spool9-west.superfeed.net> Dan Richardson arrl wrote: > Yea, four ounces should cause one hell of a droop. Droop is like dB loss - it should be minimized at all costs. :-) -- 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: 214471 of rec.radio.amateur.antenna From: "Charlie" Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Sun, 26 Jun 2005 14:47:57 -0500 Message-ID: <11bu1k0evf54aff@news.supernews.com> References: <11bsdqpir7o54fa@news.supernews.com> Thank you all very much for your kindness and courtesy in responding to my post. Typically those that berate others have significant problems with self esteem. Oh..as for those "sins"...mine are already forgiven. -- Charlie Ham Radio - AD5TH www.ad5th.com Deep South 2 Meter SSB Net www.deepsouthnet.net "Joe S." wrote in message news:d9m4jr02tvu@news4.newsguy.com... > > > "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 >> >> >> >> >> >> > > Do I understand that the guy wires terminate to trees? Is that a > permanent > arrangement? > > -- > > ----- > Joe S. > > Article: 214472 of rec.radio.amateur.antenna From: "John Smith" References: <1rttb1po7mrncf72v5v2kf8f8pmco6b5c6@4ax.com> Subject: Re: Choke baluns again Message-ID: Date: Sun, 26 Jun 2005 12:04:15 -0700 Dan: "Droop?" Hmm, I have heard about that, brits may refer to it as "brewers droop?" Or, maybe I am confused here... However, problem only seems to occur when there are pints involved... John "Dan Richardson arrl net>" wrote in message news:1rttb1po7mrncf72v5v2kf8f8pmco6b5c6@4ax.com... > On Sun, 26 Jun 2005 14:19:30 -0400, "Hal Rosser" > wrote: > >>The only thing I have against them (current baluns) is >>They are heavy. >>and cause the antenna to droop >>lowering the height of the feedpoint. >>Which is a good reason to put the balun near the radio and use >>balanced >>feedline from there to the antenna >>my 3.5 cents > > > I just weighed 50 beads that are used in W2DU's balun and came up with > a whopping 4 ounces! > > Yea, four ounces should cause one hell of a droop. > > 73, > Danny, K6MHE > > > Article: 214473 of rec.radio.amateur.antenna From: "John Smith" References: <1119747738.926814.292740@g47g2000cwa.googlegroups.com> <1119815925.888732.307890@g14g2000cwa.googlegroups.com> Subject: Re: Post anonymously Message-ID: Date: Sun, 26 Jun 2005 13:04:34 -0700 An even better way to setup anonymity is with mail2news and a remailer, it takes a bit more knowledge and work but is worth it in the long run. A google should supply one with all necessary details and tools. John "bb" wrote in message news:1119815925.888732.307890@g14g2000cwa.googlegroups.com... > > > Holly wrote: >> "bb" wrote in message >> news:1119747738.926814.292740@g47g2000cwa.googlegroups.com... >> >> >> John Smith wrote: >> > I am sure that everyone here has noticed there is much too much >> > attention paid to where posts originate from. And, there are >> > childish >> > personalities which look up where you are posting from--some with >> > malicious intent... >> > >> > This URL will provide you with a means to be anonymous: >> > http://www.antifirewall.com/news.htm >> > >> > This should allow everyone to put a stop to this bad behavior. >> > >> > John >> >> Yeh, I really don't like Robeson posting snippets of my address or >> talking about my family. >> >> >> // >> >> Of course it never dawned on you to simply ignore him, did it? >> Besides, we all know you live on Longview Street. > > Thanks Jim. Quitefine advice. > Article: 214474 of rec.radio.amateur.antenna From: "Charlie" Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Sun, 26 Jun 2005 15:51:01 -0500 Message-ID: <11bu5akmpsjhe0c@news.supernews.com> References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <6_6dncbhW4LOlCLfRVn-oA@crocker.com> Those trees have withstood every storm the past 30+ years..... Any tower can be blown down no matter what ..just let mother nature have her way. -- Charlie Ham Radio - AD5TH www.ad5th.com Deep South 2 Meter SSB Net www.deepsouthnet.net "Dave" wrote in message news:6_6dncbhW4LOlCLfRVn-oA@crocker.com... > they may be forgiven, but that won't keep a tower in the air nor make it > safer to climb. those sins are things you should seriously look at > correcting as they all affect the strength and safety of your investment > as well as anyone working on it or playing near it. > > "Charlie" wrote in message > news:11bu1k0evf54aff@news.supernews.com... >> Thank you all very much for your kindness and courtesy in responding to >> my post. >> Typically those that berate others have significant problems with self >> esteem. >> >> Oh..as for those "sins"...mine are already forgiven. >> -- >> >> Charlie >> Ham Radio - AD5TH >> www.ad5th.com >> Deep South 2 Meter SSB Net >> www.deepsouthnet.net >> >> >> >> >> >> "Joe S." wrote in message >> news:d9m4jr02tvu@news4.newsguy.com... >>> >>> >>> "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 >>>> >>>> >>>> >>>> >>>> >>>> >>> >>> Do I understand that the guy wires terminate to trees? Is that a >>> permanent >>> arrangement? >>> >>> -- >>> >>> ----- >>> Joe S. >>> >>> >> >> > > Article: 214475 of rec.radio.amateur.antenna From: "Hal Rosser" References: <1rttb1po7mrncf72v5v2kf8f8pmco6b5c6@4ax.com> Subject: Re: Choke baluns again Message-ID: Date: Sun, 26 Jun 2005 17:11:43 -0400 Add that 4 ounces to the weight of 50 feet of coax. then subtract the weight of 50 feet of balanced line that is a larger difference "Dan Richardson arrl net>" wrote in message news:1rttb1po7mrncf72v5v2kf8f8pmco6b5c6@4ax.com... > On Sun, 26 Jun 2005 14:19:30 -0400, "Hal Rosser" > wrote: > > >The only thing I have against them (current baluns) is > >They are heavy. > >and cause the antenna to droop > >lowering the height of the feedpoint. > >Which is a good reason to put the balun near the radio and use balanced > >feedline from there to the antenna > >my 3.5 cents > > > I just weighed 50 beads that are used in W2DU's balun and came up with > a whopping 4 ounces! > > Yea, four ounces should cause one hell of a droop. > > 73, > Danny, K6MHE > > > Article: 214476 of rec.radio.amateur.antenna From: Bob Miller Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <6_6dncbhW4LOlCLfRVn-oA@crocker.com> <11bu5akmpsjhe0c@news.supernews.com> Date: Sun, 26 Jun 2005 21:24:27 GMT On Sun, 26 Jun 2005 15:51:01 -0500, "Charlie" wrote: >Those trees have withstood every storm the past 30+ years..... Noticed you have metal straps around the tree trunks. The QST article of Sept '89 on using trees as antenna supports says, "Another no-no when attaching an antenna to a tree is wrapping a wire around the trunk. This strangles the veins in the sapwood the same way a noose around your neck would strangle you." bob k5qwg > >Any tower can be blown down no matter what ..just let mother nature have her >way. Article: 214477 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: momentum"Sloshing" EM Energy Date: Sun, 26 Jun 2005 16:34:21 -0500 Message-ID: <8199-42BF1F5D-394@storefull-3257.bay.webtv.net> References: <42beb22b.4515032@news.crosslink.net> Bob, W9DMK wrote: "The above paragraph was, however, a rather difficult diiffocult to understand ending---." Fair enough. Ohm`s law prevails at a-c as it does at d-c. That is, I = E / Z, just as I = E / R. If Z is a load impedance, it dictates the current it accepts. An impedance in series with the load affects the voltage applied to the load, but whatever voltage to the load is, the current through the load is related to the voltage adross the load by Ohm`s law. When a transmission line feeds a load, Ohm`s law prevails at the load Feed a certain current through and it produces a certain voltage drop. Feed a certain voltage and it allows a certain current. This is repetitious, but it`s true. The line only functions at Zo. The load only functions at its load impedance. The adjustment between these two intransigents are the forward and reverse voltages and currents whose sums make up the actual voltage and current at the load. Best regards, Richard Harrison, KB5WZI Article: 214478 of rec.radio.amateur.antenna From: Owen Subject: Re: Choke baluns again Message-ID: References: Date: Sun, 26 Jun 2005 21:53:04 GMT On Sun, 26 Jun 2005 13:37:46 +0000 (UTC), "Reg Edwards" wrote: >Questions : How effective is it? To what extent can the percentage >unbalance current on the feedline be expected to be reduced? Has >anybody ever measured it before and after insertion? Reg, I haven't measured it, however... I am in the process of modeling a balun as follow up on my G5RV feed systems analysis. The scenario is a G5RV at 10m centre height, a vertical drop of open wire line (the so called "matching section") and a balun at near ground height (with unbalanced shunt admittance introduced by the balun to ground). I have been jiggling the unbalanced shunt admittance introduced by the balun and observing the current through that admittance wrt the feedline currents, and the apparent distortion of the radiation pattern. I could nearly as easily have been comparing the current in one of the wires of the feedline wrt the other, it is just the format of the currents report that makes the former easier. Another interesting observation would be the changes to receive sensitivity to vertically polarised waves (indicating possible feedline pickup). The models indicate a few things so far: - the effect of the balun is on the unbalance current distribution on the whole feedline; - current imbalance at the base of the "matching section" of better than about -15dB caused little distortion of the pattern on 20m and below; - some configurations seem quite undesirable in terms of pattern distortion even though balun current is quite low; - raising the antenna / feedline / balun and lengthening the earth connection from the balun shunt admittance changes the current distribution. This leads me to think that measurement of the imbalance current at a single point might not give the "big picture". I found scenarios where inserting an imperfect balun increased the current at a point (it changed the magnitude of the standing wave and more importantly moved the current minimum), so I could see someone with a handy-dandy current probe measuring such a situation and insisting they have proof the baluns don't "work". Owen -- Article: 214479 of rec.radio.amateur.antenna From: "John Smith" References: Subject: Re: Choke baluns again Message-ID: <8SEve.44$eF7.1532042@news.sisna.com> Date: Sun, 26 Jun 2005 14:11:27 -0700 Reg: As usual, your posts inspire thought--and that is a GOOD thing. At least with this type of balun: http://home.datacomm.ch/hb9abx/pactor-e-choke.htm I ask, "Why not?" The insertion loss is negligible. The downside of its' use is virtually none. The upside is that in the future, as objects may come into the field close enough to couple with the antenna, or corrosion-weather-"stretch"-age-"or other factors begin to cause slight imbalances-- the balun steps in and begins enforcing a "balance." It just seems one would error on the side of caution and use such a balun. I know of few better examples of a "win-win situation." Indeed, the article Roy offered seems like one heck of an argument to this end... ... certainly someone not prepared to weigh the "fly chit" they have picked out of the pepper should just chuck one in the line and rest assured "it is a good thing." Warmest regards, John "Reg Edwards" wrote in message news:d9mb3a$de3$1@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com... >A choke balun is what is inserted between the transmitter end of the > antenna feedline and the transmitte tuner. Or it can be inserted at > the antenna end of the line. > > Questions : How effective is it? To what extent can the percentage > unbalance current on the feedline be expected to be reduced? Has > anybody ever measured it before and after insertion? > ---- > Reg. > > Article: 214480 of rec.radio.amateur.antenna From: "FDR" <_remove_spam_block_rzitka@hotmail.com> References: <90lrb1p949i59dv4la1bdm5lnid1tk74tq@4ax.com> Subject: Re: Pizza, New Great-Circle Plotting Program Message-ID: Date: Sun, 26 Jun 2005 23:07:37 GMT "K7JEB" wrote in message news:90lrb1p949i59dv4la1bdm5lnid1tk74tq@4ax.com... > > > A friend of mine, Jim Tonne, WB6BLD, has written a > much-improved, Windows version of a classic great-circle > plotting program and is providing it to the Amateur Radio > community FOR FREE. > > If you are a DX'er and need an antenna-bearing aid or just > like to poke around on the earth's geography, this program > will be of interest to you. > > It calculates the bearing and distance from a Home location > to a Target location anywhere in the world and displays this > result on both azimuthal (polar) and rectangular maps. Both > the Home and Target locations may be selected by mouse > designations on the rectangular world map or chosen from a > menu of cities, countries and callsign areas. So this tells you how to get from Home Depot to a Target store? Cool. Article: 214481 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: momentum"Sloshing" EM Energy Date: Sun, 26 Jun 2005 19:31:17 -0500 Message-ID: <17269-42BF48D5-494@storefull-3254.bay.webtv.net> References: <42beb22b.4515032@news.crosslink.net> Bob, W9MDK wrote: "The above paragraph, however, was a rather difficult to ubderstand reading,---." I responded that the load would not accept volts and amps in a ratio which does not fit its load impedance. Perhaps we should reason together some more. The transmission line delivers power to the load at its Zo. When the load impedance is different, there is a surplus of either volts or amps. The surplus nust be reflected because the load can`t take it. That`s all. Best regards, Richard Harrison, KB5WZI Article: 214482 of rec.radio.amateur.antenna From: W9DMK (Robert Lay) Subject: Re: momentum"Sloshing" EM Energy Date: Mon, 27 Jun 2005 01:01:25 GMT Message-ID: <42bf4f92.44810524@news.crosslink.net> References: <42beb22b.4515032@news.crosslink.net> <17269-42BF48D5-494@storefull-3254.bay.webtv.net> On Sun, 26 Jun 2005 19:31:17 -0500, richardharrison@webtv.net (Richard Harrison) wrote: >Bob, W9MDK wrote: >"The above paragraph, however, was a rather difficult to ubderstand >reading,---." > >I responded that the load would not accept volts and amps in a ratio >which does not fit its load impedance. Perhaps we should reason together >some more. The transmission line delivers power to the load at its Zo. >When the load impedance is different, there is a surplus of either volts >or amps. The surplus nust be reflected because the load can`t take it. >That`s all. > >Best regards, Richard Harrison, KB5WZI > Dear Richard, Actually, your previous response was much more than I really expected. I just wanted to see different wording on the original paragraph. You've done a good job, and I hope everyone took good notes - Hi! 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: 214483 of rec.radio.amateur.antenna From: "Joe S." Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Sun, 26 Jun 2005 20:47:55 -0500 Message-ID: References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <6_6dncbhW4LOlCLfRVn-oA@crocker.com> <11bu5akmpsjhe0c@news.supernews.com> "Charlie" wrote in message news:11bu5akmpsjhe0c@news.supernews.com... > Those trees have withstood every storm the past 30+ years..... > > Any tower can be blown down no matter what ..just let mother nature have her > way. > > -- > > Charlie > Ham Radio - AD5TH > www.ad5th.com > Deep South 2 Meter SSB Net > www.deepsouthnet.net > No, any tower cannot blow down no matter what. A properly installed tower, installed to manufacturer's specs, will withstand at least the wind load specified by the manufacturer. In my initial reply in which I pointed out that the tower was guyed to one or more trees, I was trying to be nice. Now that others have chimed in, no more nice guy. That piece of shit will come down on your house, possibly on neighbors' houses, and possibly on a power line. And when it does, this is a little bit of what will happen: -- your homeowner's insurance company will send out a tower engineer to check the wreckage and will refuse to pay one penny. -- your neighbors will sue for damages, their insurance companies will send out real tower engineers to inspect, and your homeowner's liability insurance will not pay a penny. -- the power company will send out their engineers and will charge you to repair the damage to their lines and equipment. -- you'll be damn lucky if no one is killed or injured when it comes down. And if anyone is, you could be looking at jail time, depending on whether or not your local prosecuting attorney wants to be a badass. Here is a short list of problems with your tower: -- not installed any way close to manufacturer's specs -- mixed parts of different towers; what the hell is a "Sears" tower? Intended for TV antenna use? There is a BIG difference between real towers (Rohn) and make-believe towers. -- base is a joke; a guyed 50-foot 25G requires 1.5 cubic yards of concrete. You are supporting 75 feet with less than a yard. -- base is an even bigger joke when you consider that you used a homemade, non-galvanized base plate welded to some odd pieces of pipe buried a couple of feet in the ground. Welds are not cleaned and galvanized -- they will rust and break. Did you ever stop to think why tower parts are hot-dipped galvanized? -- guyed to trees. Problem is not that the trees will come down, problem is that in a big blow, the trees will sway one way, pulling the guy wires with them, while the tower is swaying in the other direction, thereby popping the guy wires. -- guyed to power pole. Did you clear this with the local power company first? When they discover what you have done to their pole, you'll need a lawyer and a big bank account. -- too close to house -- when that thing comes down, it'll take out a big piece of house. -- no thrust bearing so all the whipping around the mast will do will be absorbed by the rotator. But that's okay, when the tower comes down you can replace the rotator by standing on the ground. -- did you use high-tensile steel for the mast or another piece of Radio Shack junk? I'll look for you in QST -- Silent Keys in a couple of months. -- ----- Joe S. > > > > > "Dave" wrote in message > news:6_6dncbhW4LOlCLfRVn-oA@crocker.com... > > they may be forgiven, but that won't keep a tower in the air nor make it > > safer to climb. those sins are things you should seriously look at > > correcting as they all affect the strength and safety of your investment > > as well as anyone working on it or playing near it. > > > > "Charlie" wrote in message > > news:11bu1k0evf54aff@news.supernews.com... > >> Thank you all very much for your kindness and courtesy in responding to > >> my post. > >> Typically those that berate others have significant problems with self > >> esteem. > >> > >> Oh..as for those "sins"...mine are already forgiven. > >> -- > >> > >> Charlie > >> Ham Radio - AD5TH > >> www.ad5th.com > >> Deep South 2 Meter SSB Net > >> www.deepsouthnet.net > >> > >> > >> > >> > >> > >> "Joe S." wrote in message > >> news:d9m4jr02tvu@news4.newsguy.com... > >>> > >>> > >>> "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 > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>> > >>> Do I understand that the guy wires terminate to trees? Is that a > >>> permanent > >>> arrangement? > >>> > >>> -- > >>> > >>> ----- > >>> Joe S. > >>> > >>> > >> > >> > > > > > > Article: 214484 of rec.radio.amateur.antenna From: richardharrison@webtv.net (Richard Harrison) Subject: Re: momentum"Sloshing" EM Energy Date: Sun, 26 Jun 2005 21:01:57 -0500 Message-ID: <10915-42BF5E15-583@storefull-3256.bay.webtv.net> References: <42bf4f92.44810524@news.crosslink.net> Bob, W9MDK wrote: "Actually, your previous response was much more than I expected." Bob Lay is a well known designer and author. I appreciate his criticisms and comments as I appreciate those of Cecil, Ian, Richard C., Walter, and others. I make mistakes and typos, but can`t blame the shakes. My problems are fuzzy sight and forgetfulness. I`ve never taught, or written for magazines or books. I`m just a perpetual student. I`ve learned a lot here. Thank you to all of you who have taught me much. I always read what Reg, Roy, and Wes have to say. They are rich information sources. There are many more great contributors, but I could not begin to name them all. Some of the conflicts are roll on the floor funny. I thoroughly enjoy them as an observer. Thanks for the memories. Best regards, Richard Harrison, KB5WZI Article: 214485 of rec.radio.amateur.antenna Subject: Re: AD5TH Tower Project Completed - Pics Online From: Ed References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <6_6dncbhW4LOlCLfRVn-oA@crocker.com> <11bu5akmpsjhe0c@news.supernews.com> Message-ID: Date: Mon, 27 Jun 2005 02:18:00 GMT "Charlie" wrote in news:11bu5akmpsjhe0c@news.supernews.com: > Those trees have withstood every storm the past 30+ years..... > > Any tower can be blown down no matter what ..just let mother nature > have her way. > Well, Charlie, those trees have withstood mother nature up til now. Whether or not they are healthy, they now are supporting a 90 foot tower, in addition to their own wind load. Things are different now. As far as ANY tower can be blown down.... not really true for a properly engineered and maintained structure. Ed K7AAT Article: 214486 of rec.radio.amateur.antenna From: "Walter Maxwell" References: <11bhipmf68alnae@corp.supernews.com> <1119420226.578082.298220@g44g2000cwa.googlegroups.com> <1119473509.849447.88080@g44g2000cwa.googlegroups.com> <1119474987.959994.179880@g44g2000cwa.googlegroups.com> <4c8nb19026dq2vkt2hq40jftqh6jvhcgl7@4ax.com> <42bc2d46$1_2@spool9-west.superfeed.net> Subject: Re: Caculating VSWR from rho and rho from VSWR Message-ID: Date: Sun, 26 Jun 2005 23:07:01 -0400 "Cecil Moore" wrote in message news:42bc2d46$1_2@spool9-west.superfeed.net... > Tom Donaly wrote: >> Nothing, short of >> a visitation by The Creator will make some of the correspondents >> to this newsgroup change their thinking about how transmission >> lines behave. > > Hey Tom, what do you think about Ramo & Whinnery's assertion > in _Fields_and_Waves_... 2nd edition, page 291 " .. we are > often most interested in the ratio of power in the reflected > wave to that in the incident wave, and this ratio is given > by the square of the magnitude of [rho], as can be shown by > considering the Poynting vectors: Pz-/Pz+ = |rho|^2 (3)" > > Note the plural "Poynting vectors", Pz- for reflected power > and Pz+ for forward power. > -- > 73, Cecil, http://www.qsl.net/w5dxp > Cecil, concerning Poynting vectors, may I refer you to the last paragraph of Page 8-3 in Reflections 1, or the last paragraph beginning on Page 8-2 of Reflections 2. Walt, W2DU Article: 214487 of rec.radio.amateur.antenna From: "Charlie" Subject: Re: AD5TH Tower Project Completed - Pics Online Date: Sun, 26 Jun 2005 22:26:44 -0500 Message-ID: <11busgftdv3a821@news.supernews.com> References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <6_6dncbhW4LOlCLfRVn-oA@crocker.com> <11bu5akmpsjhe0c@news.supernews.com> Thank you Joe for your unsolicited candor..... -- Charlie Ham Radio - AD5TH www.ad5th.com Deep South 2 Meter SSB Net www.deepsouthnet.net "Joe S." wrote in message news:d9nls20sbi@news1.newsguy.com... > > "Charlie" wrote in message > news:11bu5akmpsjhe0c@news.supernews.com... >> Those trees have withstood every storm the past 30+ years..... >> >> Any tower can be blown down no matter what ..just let mother nature have > her >> way. >> >> -- >> >> Charlie >> Ham Radio - AD5TH >> www.ad5th.com >> Deep South 2 Meter SSB Net >> www.deepsouthnet.net >> > > No, any tower cannot blow down no matter what. A properly installed > tower, > installed to manufacturer's specs, will withstand at least the wind load > specified by the manufacturer. > > In my initial reply in which I pointed out that the tower was guyed to one > or more trees, I was trying to be nice. Now that others have chimed in, > no > more nice guy. > > That piece of shit will come down on your house, possibly on neighbors' > houses, and possibly on a power line. And when it does, this is a little > bit of what will happen: > -- your homeowner's insurance company will send out a tower engineer to > check the wreckage and will refuse to pay one penny. > -- your neighbors will sue for damages, their insurance companies will > send > out real tower engineers to inspect, and your homeowner's liability > insurance will not pay a penny. > -- the power company will send out their engineers and will charge you to > repair the damage to their lines and equipment. > -- you'll be damn lucky if no one is killed or injured when it comes down. > And if anyone is, you could be looking at jail time, depending on whether > or > not your local prosecuting attorney wants to be a badass. > > Here is a short list of problems with your tower: > -- not installed any way close to manufacturer's specs > -- mixed parts of different towers; what the hell is a "Sears" tower? > Intended for TV antenna use? There is a BIG difference between real > towers > (Rohn) and make-believe towers. > -- base is a joke; a guyed 50-foot 25G requires 1.5 cubic yards of > concrete. > You are supporting 75 feet with less than a yard. > -- base is an even bigger joke when you consider that you used a homemade, > non-galvanized base plate welded to some odd pieces of pipe buried a > couple > of feet in the ground. Welds are not cleaned and galvanized -- they will > rust and break. Did you ever stop to think why tower parts are hot-dipped > galvanized? > -- guyed to trees. Problem is not that the trees will come down, problem > is > that in a big blow, the trees will sway one way, pulling the guy wires > with > them, while the tower is swaying in the other direction, thereby popping > the > guy wires. > -- guyed to power pole. Did you clear this with the local power company > first? When they discover what you have done to their pole, you'll need a > lawyer and a big bank account. > -- too close to house -- when that thing comes down, it'll take out a big > piece of house. > -- no thrust bearing so all the whipping around the mast will do will be > absorbed by the rotator. But that's okay, when the tower comes down you > can > replace the rotator by standing on the ground. > -- did you use high-tensile steel for the mast or another piece of Radio > Shack junk? > > I'll look for you in QST -- Silent Keys in a couple of months. > > > -- > > ----- > Joe S. > >> >> >> >> >> "Dave" wrote in message >> news:6_6dncbhW4LOlCLfRVn-oA@crocker.com... >> > they may be forgiven, but that won't keep a tower in the air nor make >> > it >> > safer to climb. those sins are things you should seriously look at >> > correcting as they all affect the strength and safety of your >> > investment >> > as well as anyone working on it or playing near it. >> > >> > "Charlie" wrote in message >> > news:11bu1k0evf54aff@news.supernews.com... >> >> Thank you all very much for your kindness and courtesy in responding >> >> to >> >> my post. >> >> Typically those that berate others have significant problems with self >> >> esteem. >> >> >> >> Oh..as for those "sins"...mine are already forgiven. >> >> -- >> >> >> >> Charlie >> >> Ham Radio - AD5TH >> >> www.ad5th.com >> >> Deep South 2 Meter SSB Net >> >> www.deepsouthnet.net >> >> >> >> >> >> >> >> >> >> >> >> "Joe S." wrote in message >> >> news:d9m4jr02tvu@news4.newsguy.com... >> >>> >> >>> >> >>> "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 >> >>>> >> >>>> >> >>>> >> >>>> >> >>>> >> >>>> >> >>> >> >>> Do I understand that the guy wires terminate to trees? Is that a >> >>> permanent >> >>> arrangement? >> >>> >> >>> -- >> >>> >> >>> ----- >> >>> Joe S. >> >>> >> >>> >> >> >> >> >> > >> > >> >> > > Article: 214488 of rec.radio.amateur.antenna From: "Hal Rosser" References: <1rttb1po7mrncf72v5v2kf8f8pmco6b5c6@4ax.com> Subject: Re: Choke baluns again Message-ID: Date: Sun, 26 Jun 2005 23:56:09 -0400 "Dan Richardson arrl net>" wrote in message news:qt6ub1tq6825jenh7f49j64tlcnsv10shv@4ax.com... > In your original post you said: > > "The only thing I have against them (current baluns) is > They are heavy. > and cause the antenna to droop lowering the height of the feedpoint." > > Anyway, with say fifty pounds of tension just how much drop are you > talking about? And what difference does it make? > Apparently it makes more difference to me than it does to you. I don't want it digging into the tree branches. Nothing wrong with your view - its probably a better-informed view than mine - but I'll still use balanced line and I still think baluns are too heavy. I'm just hard-headed that way. :-) Article: 214489 of rec.radio.amateur.antenna From: "Leonard Kubiak" References: Subject: Re: Attic antenna: rotator upside-down work? Message-ID: Date: Mon, 27 Jun 2005 04:06:13 GMT How about buying a rotor manufactured in Austrailla......Problem solved.,........ Article: 214490 of rec.radio.amateur.antenna From: "John Smith" References: <11bsdqpir7o54fa@news.supernews.com> <11bu1k0evf54aff@news.supernews.com> <6_6dncbhW4LOlCLfRVn-oA@crocker.com> <11bu5akmpsjhe0c@news.supernews.com> <11busgftdv3a821@news.supernews.com> Subject: Re: AD5TH Tower Project Completed - Pics Online Message-ID: Date: Sun, 26 Jun 2005 20:44:47 -0700 ... Joe S. was a bit harsh. However, I have a cousin who is a mucky-muck in the "insurance scam", frankly it is my belief that some of those guys would beat pennies out of widows if it paid enough. If it were me, I'd see if I couldn't work on the tree thing a bit and set up some steel-galvanized pipes set in a generous block of concrete and perhaps tied to deadmen to make sure the "insurance thieves" did not find a new victim in me... ... I have about the same respect for insurance people as I do for lawyers, since the supreme court decision on confiscation of private property--they now join those ranks--the constitution seems damn clear on the point to me--indeed, I would expect any high school kid with a proper course in american history to make a better decision than they managed--so nothing surprises me--and for that reason I'd always plan for the worse... John "Charlie" wrote in message news:11busgftdv3a821@news.supernews.com... > Thank you Joe for your unsolicited candor..... > > -- > > Charlie > Ham Radio - AD5TH > www.ad5th.com > Deep South 2 Meter SSB Net > www.deepsouthnet.net > > > > > > "Joe S." wrote in message > news:d9nls20sbi@news1.newsguy.com... >> >> "Charlie" wrote in message >> news:11bu5akmpsjhe0c@news.supernews.com... >>> Those trees have withstood every storm the past 30+ years..... >>> >>> Any tower can be blown down no matter what ..just let mother nature >>> have >> her >>> way. >>> >>> -- >>> >>> Charlie >>> Ham Radio - AD5TH >>> www.ad5th.com >>> Deep South 2 Meter SSB Net >>> www.deepsouthnet.net >>> >> >> No, any tower cannot blow down no matter what. A properly installed >> tower, >> installed to manufacturer's specs, will withstand at least the wind >> load >> specified by the manufacturer. >> >> In my initial reply in which I pointed out that the tower was guyed >> to one >> or more trees, I was trying to be nice. Now that others have chimed >> in, no >> more nice guy. >> >> That piece of shit will come down on your house, possibly on >> neighbors' >> houses, and possibly on a power line. And when it does, this is a >> little >> bit of what will happen: >> -- your homeowner's insurance company will send out a tower engineer >> to >> check the wreckage and will refuse to pay one penny. >> -- your neighbors will sue for damages, their insurance companies >> will send >> out real tower engineers to inspect, and your homeowner's liability >> insurance will not pay a penny. >> -- the power company will send out their engineers and will charge >> you to >> repair the damage to their lines and equipment. >> -- you'll be damn lucky if no one is killed or injured when it comes >> down. >> And if anyone is, you could be looking at jail time, depending on >> whether or >> not your local prosecuting attorney wants to be a badass. >> >> Here is a short list of problems with your tower: >> -- not installed any way close to manufacturer's specs >> -- mixed parts of different towers; what the hell is a "Sears" tower? >> Intended for TV antenna use? There is a BIG difference between real >> towers >> (Rohn) and make-believe towers. >> -- base is a joke; a guyed 50-foot 25G requires 1.5 cubic yards of >> concrete. >> You are supporting 75 feet with less than a yard. >> -- base is an even bigger joke when you consider that you used a >> homemade, >> non-galvanized base plate welded to some odd pieces of pipe buried a >> couple >> of feet in the ground. Welds are not cleaned and galvanized -- they >> will >> rust and break. Did you ever stop to think why tower parts are >> hot-dipped >> galvanized? >> -- guyed to trees. Problem is not that the trees will come down, >> problem is >> that in a big blow, the trees will sway one way, pulling the guy >> wires with >> them, while the tower is swaying in the other direction, thereby >> popping the >> guy wires. >> -- guyed to power pole. Did you clear this with the local power >> company >> first? When they discover what you have done to their pole, you'll >> need a >> lawyer and a big bank account. >> -- too close to house -- when that thing comes down, it'll take out a >> big >> piece of house. >> -- no thrust bearing so all the whipping around the mast will do will >> be >> absorbed by the rotator. But that's okay, when the tower comes down >> you can >> replace the rotator by standing on the ground. >> -- did you use high-tensile steel for the mast or another piece of >> Radio >> Shack junk? >> >> I'll look for you in QST -- Silent Keys in a couple of months. >> >> >> -- >> >> ----- >> Joe S. >> >>> >>> >>> >>> >>> "Dave" wrote in message >>> news:6_6dncbhW4LOlCLfRVn-oA@crocker.com... >>> > they may be forgiven, but that won't keep a tower in the air nor >>> > make it >>> > safer to climb. those sins are things you should seriously look >>> > at >>> > correcting as they all affect the strength and safety of your >>> > investment >>> > as well as anyone working on it or playing near it. >>> > >>> > "Charlie" wrote in message >>> > news:11bu1k0evf54a