Subject: GLOWBUGS digest 360

From: [email-masked]
Date: Fri, 22 Nov 1996 10:56:53 -0600 (CST)

GLOWBUGS Digest 360

Topics covered in this issue include:

  1) 
	by [email-masked] (John Heck)
  2) Re: regen designs --- use of an rf stage
	by [email-masked]
  3) Re: regen sets with/without rf stages (cont.)
	by [email-masked]
  4) Re: DX-100 manual 
	by "Thomas J. Whalen" <[email-masked]>
  5) A lathe of your own
	by [email-masked] (Jeff Duntemann)
  6) Handbooks please?
	by Glenn Finerman <[email-masked]>
  7) Re: Handbooks please?
	by [email-masked] (Jeff Duntemann)
  8) "How to Make a Short Wave Receiver"
	by [email-masked] (John Levreault)
  9) Re: regen designs
	by [email-masked] (Murray Kelly)
 10) Re: "How to Make a Short Wave Receiver"
	by [email-masked] (John Heck)
 11) 80 Meter Transceiver
	by [email-masked] (Randy Pelt)
 12) Duelling Hartleys it were on the BA/GB QRG
	by [email-masked]

----------------------------------------------------------------------

Date: Thu, 21 Nov 96 12:08:07 EST
From: [email-masked] (John Heck)
To: [email-masked]
Message-ID: <[email-masked]>

Folks,
I have been accumulating parts for the 2 tube regen plan listed in the 1946 ARRL
handbook. I made my own chassis and front panel from a  garage sale "liberated"
road sign(hard as h**l to bend with no brake!) and was happy as a pig in s**t until
Forrest Snyder kindly sent me a copy of an article from the September 1992 QST. "A
40-Meter Regenerative Receiver You Can Build", by David Newkirk, suggested strongly
that any regen should have an RF stage ahead of the detector for several reasons. 
Among them were the ability to throttle down the signal from strong stations to im-
prove selectivity, help to eliminate the effects of hand capactiance, eliminate dead
spots by isolating the detector from the antenna, and greatly reducing self radiation.
These seemed to me to be important considerations. They seemed to add a lot of value
for really little extra cost or work. Alas, my chosen design does not include an RF
stage. I would appreciate some discussion concerning Mr. Newkirks points on this sub-
ject. Does an RF stage really buy you that much benefit? Can an RF stage be easily
added to about any design without a major rework? or is it better to build from a
design which included an RF stage from the get-go?

Mr. Newkirk claims that his design is falls in line with the regen design philosophy 
exemplified in G. Grammer's QST article of 1933, "Rationalizing the Autodyne", adher-
ance to which, he claims, produces the "Cadillac" of regen designs. His design follows
Grammer, he says, except that Newkirk adds an additional stage of audio. He uses a
6GH8A for RF Amp/Detector and a 6GH8A for Audio1/Audio2, and the radio is fixed band
at 40 meters.

I'm not yet sure I'm going to build this design as I want a general coverage radio,
but his points are well taken and *seem* to be soundly thought out, with a lot of
historical precedence. In addition, I've never yet read a regen building article
which gave so much operational theory and so many operating instructions. It's a 
must read for anybody building or operating a regen(unless you read the Grammer
article when that issue just came out ;^). I'll send anybody a copy who sends me a
business size SASE. Don't bother Forrest, since I'm the one who drew attention to
the piece. This would sure be a good one for the plans databank.
Regards,
John Heck, KC8ETS
1009 Donson Drive
Dayton, Ohio 45429
(513)865-7036(work)
[email-masked]

------------------------------

Date: Thu, 21 Nov 1996 14:04:46 -0500 (EST)
From: [email-masked]
To: [email-masked]
Cc: [email-masked] (), [email-masked]
Subject: Re: regen designs --- use of an rf stage
Message-ID: <[email-masked]>

The main point to garner from Newkirk's article (as well as Grammer's),
is that the addition of an RF stage ISOLATES the regen detector from
the antenna.  The main reason for doing that is to keep the OO's happy
by reducing antenna radiation.  In a properly designed regen set, it has
little effect on selectivity.  Also, any shielding helps to reduce stray
pickup of loud local AM signals, etc.  Combine shielding and the rf stage,
and you have a much less tempermental regen detector, relatively speaking,
although in my hands, the unshielded non-isolated classic 2 or 3 tuber
works very well, if properly designed, and the rf output of the thing on
low voltages (approximately 48 or less) is only a milliwatt or two.
Now, to some qrp folks that will get you quite a ways, but generally,
that can't be heard more than a few miles.  My neighbor, 300 yards up the
road can hear mine, but my other neighbor a mile away, usually can't hear
it at all.

The most important things that I have found in regens are:

1.  Keep the coupling LOOSE for maximum selectivity.  The antenna
    coupling should be loose AND the tube coupling should be loose
    (use a highvvalue grid leak of 10 meg ohms and a low value grid
    coupling cap of 10pf, for best results, at HF). 

2.  Keep the circuit construction as high-Q as possible.

4.  Keep the parts well mounted to prevent vibration effects.

5.  Keep the parts well behind the front panel or use shielding
    on the front panel or both, and ground the tuning dial if used,
    to minimise hand capacity effects.

This makes any regen sensitive and selective.

If you want to study the finest in regenerative receiver designs, study
a) the IP-501A, and b) the RAL.  They are the cream of the commercial
crop.  Hams will have a hard time doing much better than these.  Go
read Grammer's and Newkirk's articles, though, they are great reading!

73/ZUT DE NA4G/Bob UP

------------------------------

Date: Thu, 21 Nov 1996 15:06:54 -0500 (EST)
From: [email-masked]
To: [email-masked]
Cc: [email-masked] (), [email-masked]
Subject: Re: regen sets with/without rf stages (cont.)
Message-ID: <[email-masked]>

> Folks,
> I have been accumulating parts for the 2 tube regen plan listed in the 1946
> ARRL handbook.

Sounds GREAT!

For e-mailing folks, can we keep our lines to under 77 characters,
please.  It seems to happen most often with folks using windoz
based emailers.  This is a 77 character line:

1234567890123456789012345678901234567890123456789012345678901234567

That way, ascii emailers will not inadvertently fold lines when the
beginning > is added to a reply line in an email message, OK?
The blame is to those who designed mailers using non-standard fonts,
and not to the list.  I do suggest that it will make reading mail
easier for all.

> Forrest Snyder kindly sent me a copy of an article from the September 1992
> QST. ``A 40-Meter Regenerative Receiver You Can Build", by David Newkirk,
> suggest strongly that any regen should have an RF stage ahead of the
> detector for several reasons.  Among them were the ability to throttle
> down the signal from strong stations to improve selectivity,

The RF stage only allows one to throttle down the signal from 
strong stations, in that it allows you to control the receiver gain.
In most regen receivers, the rf gain is used to control the overall
receiver gain, and the audio is run wide open, or at least it should
be.

The same thing is accomplished in a receiver without an RF stage by
uncoupling the antenna to a lesser or greater degree from the
input detector tuning coil system.  How this is done does not really
matter.  In the early days, sliding coils or swinging links or some
sort of variometer was used.  In later days, a variable input
coupling capacitor of, for example, 3-30pf was used.  I prefer to
physically uncouple the coil rather than try to electronically
uncouple it.  It works better in my hands.  The early WWI sets did
it right in my estimation.  Cheaper later designs forgot how to
do it right.

> help to eliminate the effects of hand capactiance,

I will have to differ with folks on this one.  The use of an RF
stage has absolutely nothing to do with the effect of hand
capacitance on a regenerative detector.  It DOES have to do with
the effect of variations in antenna capacitance (typically from
the swinging of the antenna in the wind) altering the tuning of
the detector slightly.  The occurs mostly when the detector has
been overcoupled to the antenna system, and not when it has been
properly coupled into the antenna system.

Hand capacity effects are due to the physical proximity of the
operator's body parts to the oscillating detector tuned circuit.
In the old days, the solution was to physically move the parts
back from the front panel by some 6 to 12 inches and use long
shafts on the tuning controls.  Hams typically did this in the
early and middle 1920's.  As early as 1911, commercial spark
sets used a thin sheet of copper behind the panel to reduce hand
capacity effects.  This was often used by hams in the middle and
late 1920's and early 1930's.  This works fine, as long as the
sheet is grounded and the dial mechanism, if used is grounded.
By 1930, some hams were using complete metallic shielding on
their regen sets, and this was becoming general practice by
1935.  After 1935, most folks used some form of shielding or a
shielded chassis, except on the very lowest-endian regen sets.

> eliminate dead spots by isolating the detector from the antenna,

This is done by the isolation of the detector stage by the RF stage.
It is also done on sets without an RF stage by LOOSE COUPLING the
detector to the antenna system.  Folks, if you never learn anything
else about regens and self-excited oscillator transmitters, you MUST
learn that best operation is obtained with the loosest practical
amount of coupling.  A regen detector is extremely sensitive all the
way down to the noise floor at HF, especially on the lower bands of
160/80/40, that we are likely to use such regens on.  Thus you don't
use the antenna as a pickup as much as you use it as a conductor to
get the signal into the detector.  Overcoupling is the greatest way
to kill a good regen detector, bar none.

> and greatly reducing self radiation.

This is the main reason that everyone used and still uses the RF
stage on a regenerative detector.  It will reduce the autodyne
carrier by 10-30 db, coupled with proper shielding.

> These seemed to me to be important considerations. They seemed to add a lot of value
> for really little extra cost or work. Alas, my chosen design does not include an RF
> stage. I would appreciate some discussion concerning Mr. Newkirks points on this sub-
> ject. Does an RF stage really buy you that much benefit?

In comparing regen receivers with and without an RF stage, I find
that the RF stage only serves to isolate the detector and give you
a volume/sensitivity control on multistage sets.  Even on the RAL,
the two stages of RF only serve to act as a general passband filter
and mostly as a volume control mechanism.  The use of the RF stage
DOES greatly help to reduce inband overloading.  For example, when
my buddies up and down the street get on 80M, the unshielded, NON-
RF stage set will be swamped, unless I GREATLY uncouple the antenna
from the set.  When I use the RAL, I can completely root out the
interference of W1AW, the traffic handlers who freqent 3580.0, and
the traffic handlers on 3578.0, in addition to my neighbors (which
will also swamp the wide-open front end in my HW-16).  In this case,
the selectivity is as a passband due to the two stages of RF ahead
of the detector.  The detector is already operating at about a 1khz
bandwidth or less.  The rf stages merely steepen up the passband
skirts.  That way, 3579.545 is a pleasure to operate on.

> Can an RF stage be easily added to about any design without a major rework?

Quite simply.  In the 30's Grammer used an outboard RF stage as a
separate box.  Some manufacturers touted them as ``preselectors''.
The novice regens of the late 40's and early 50's often had an RF
stage that could be added outboard to the main set.

Also, if you are building the set from scratch, the addition of an
RF stage is trivial.  Just copy any good rf stage from any ham
receiver or any handbook.  They will all work, generically, about
the same, on low HF. 

> Or, is it better to build from a design which included an RF stage from the
> get-go?

Really makes no difference.  Sets designed with the RF stage were
usually sets that once did not have an RF stage.  So, go figure.
That is how the handbooks started off with something simple like
the traditional 2-tube, and grew it up to the fancier 3/4/5 tuber
trf autodyne sets.

> 
> Mr. Newkirk claims that his design is falls in line with the regen design philosophy 
> exemplified in G. Grammer's QST article of 1933, "Rationalizing the Autodyne", adher-
> ance to which, he claims, produces the "Cadillac" of regen designs. His design follows
> Grammer, he says, except that Newkirk adds an additional stage of audio. He uses a
> 6GH8A for RF Amp/Detector and a 6GH8A for Audio1/Audio2, and the radio is fixed band
> at 40 meters.

Although I have not seen Dave's article in a year or two, I would offer
as the caddilac example of regen receiver design, the classic RCA RAL-7
receiver, used by the military from 1937-1965 or so.  It is hard to beat
under any circumstances for a regen set.  It has filtering that is as 
good as most modern ricenboxen, and better than many.  Alas, it has no
fancy digital readout, just a 0-1000 logging dial.

Both Grammer's and Newkirk's articles are good reading.  Also, you
should consult Sterling's Radio Manual, 1st, 3rd, and 4th editions
for very good background and examples in regen sets, and how they
developed between 1927 and 1952.

73/ZUT DE NA4G/Bob UP

------------------------------

Date: Thu, 21 Nov 1996 13:14:30 -0700 (MST)
From: "Thomas J. Whalen" <[email-masked]>
To: Multiple recipients of list <[email-masked]>
Subject: Re: DX-100 manual 
Message-ID: <[email-masked]>

Hi All, I have been building glowbug rigs for a couple of month now and 
sure having fun! I was just given a dx-100 and need a manual or a little 
info on it. I can get it to come on but when I plug in the key I get no 
output. Is there a t/r connection on the back or what??? Thanks Tom WB5QYT

------------------------------

Date: Thu, 21 Nov 1996 13:26:52 -0700
From: [email-masked] (Jeff Duntemann)
To: [email-masked]
Subject: A lathe of your own
Message-ID: <[email-masked]>

Hi gang--

I got a recent sale catalog from Enco and they list an interesting device
that people here should know about.  It's a real metal-turning bench lathe,
7" swing and 10" between centers.  It's quite small, and very cheap: only
$479 new.

I bought a lathe in 1988, and it's been spectacularly useful for
homebrewing, largely in winding coils and making small shaft fittings for
dials and such.  Lathes make it possible to create a perfectly round metal
or plastic disk for vernier dials, too.

Their new 96-97 full-line catalog is now available, too.  It's one of the
best tool catalogs I get regularly.  (And I swear I get every catalog in the
civilized galaxy...)  I've bought lots of stuff from them over the years and
never gotten messed-over; the drill press they sold me in 1976 works as good
as new--and it's done a *lot*.

Enco Manufacturing
5000 W. Bloomingdale
Chicago IL 60639

1-800-860-3400

--73--

--Jeff Duntemann KG7JF
  Scottsdale, Arizona

------------------------------

Date: Thu, 21 Nov 1996 15:58:38 -0500
From: Glenn Finerman <[email-masked]>
To: [email-masked]
Subject: Handbooks please?
Message-ID: <[email-masked]>

I've completed the first step in the "Glowbugs Cookbook" project by
copying all the xmtr and VFO projects from my 1956 handbook.
Now I need more material!!....How about it folks? Does anybody have
a duplicate 50's handbook they would be willing to part with?
I'm not sure all the xmtr projects that appeared in QST made it
to the Handbook and visa-versa, so I would also be interested in
duplicate QST's from the 50's that contain xmtr and VFO projects.
Just a reminder, all those who contribute will receive a free copy
of the cookbook when it's done.

Thanks!!.................Glenn     N2BJG    [email-masked]

------------------------------

Date: Thu, 21 Nov 1996 15:01:32 -0700
From: [email-masked] (Jeff Duntemann)
To: [email-masked]
Cc: [email-masked]
Subject: Re: Handbooks please?
Message-ID: <[email-masked]>

At 03:00 PM 11/21/96 -0600, you wrote:
>I've completed the first step in the "Glowbugs Cookbook" project by
>copying all the xmtr and VFO projects from my 1956 handbook.
>Now I need more material!!....How about it folks? Does anybody have
>a duplicate 50's handbook they would be willing to part with?

Actually, some of the best (or at least the most duplicatable) tube projects
appeared in ARRL Handbooks of the early 1960s.  A lot of parts in common use
in the 50's (basically pre-made plug-in coils, odd IF cans, and such) are
long gone now, and by the Sixties were less used.

My favorite two years are 1964 and 1965.  After that, solid state began to
dominate the book.

--73--

--Jeff Duntemann KG7JF
  Scottsdale, Arizona

------------------------------

Date: Thu, 21 Nov 1996 19:01:25 -0500 (EST)
From: [email-masked] (John Levreault)
To: [email-masked]
Subject: "How to Make a Short Wave Receiver"
Message-ID: <[email-masked]>

Help!

Can somebody help me identify this? It's a 70-page magazine style
publication with the above title. Unfortunately, the covers are missing and
nowhere is it otherwise identified.

The only date reference I can find is in the ads in the back where one ad
sez 1934. It's a great rag, with all kinds of regen, superhet, and
superrengen receivers, tips on operation and performance, even a push-pull
audio amp with 45's. The first article is entitled "The S.W.C. Two Tube
Portable Works Speaker", which includes the design of a folding horn for the
loudspeaker.

Any help in identifying this would be appreciated.

73 de NB1I
John Levreault

------------------------------

Date: Fri, 22 Nov 96 19:38:09 AES
From: [email-masked] (Murray Kelly)
To: [email-masked]
Cc: [email-masked]
Subject: Re: regen designs
Message-ID: <[email-masked]>

The reference to an RF stage pre-regen detector as an isolator to 
re-radiation prompted 2 thoughts. (some sort of record?).

Anyway - there is a most thoughtful discussion of regens as
general coverage Rx in the RSGB Technical Topics Scrapbook
1985-1989 pp162-163. There is even a circuit using a twin
triode and a triode pentode. There is NO RF stage. The writer
Alan Radmore RS88565 (the UK has registered listeners still)
decidede to build himself a regen after the old ways and explains
how successful it was. His advantage was the availablity of plug-in
coils commercially.

One point he made was the effectiveness of an antenna attenuator
using a dual gang pot of 10K A. The wipers are paralleled and the 
anti-clockwise end of the tracks grounded. One top end of one is 
the antenna input and the other top end goes to the tank. He reports 
that once set he rarely has to adjust it. Well worth a look if you 
can get your hands on a copy.

The other thing that came into my mind was - does a toroid tank in
a regen Rx radiate less than a solenoid coil? The only connection to
the outside world is the short wire antenna. This may overcome some
of the objections I have had from OTs when I suggest I want try my
hand at a regen Rx using a tube. Evidently transistor regends don't
radiate??? That's  the impression they try to foist on me.

Comments?

Cheers. Murray
******************************************************************
*      Murray Kelly vk4aok      [email-masked]         *
*      29 Molonga Ter. / Graceville/ QLD. 4075/ Australia        *
*      ph/fax Intl+ 61 7 3379 3307  mobile 018 071 355           *
******************************************************************

------------------------------

Date: Fri, 22 Nov 96 08:38:03 EST
From: [email-masked] (John Heck)
To: [email-masked], [email-masked]
Subject: Re: "How to Make a Short Wave Receiver"
Message-ID: <[email-masked]>

John,
This is an issue of the magazine "Short Wave Craft" published in the early-mid
thirties. I have several issues. It's a Hugu Gernsback publication.
Regards,
John Heck, KC8ETS
1009 Donson Drive
Dayton, Ohio 45429
(513)865-7036(work)
[email-masked]

> Help!
> 
> Can somebody help me identify this? It's a 70-page magazine style
> publication with the above title. Unfortunately, the covers are missing and
> nowhere is it otherwise identified.
> 
> The only date reference I can find is in the ads in the back where one ad
> sez 1934. It's a great rag, with all kinds of regen, superhet, and
> superrengen receivers, tips on operation and performance, even a push-pull
> audio amp with 45's. The first article is entitled "The S.W.C. Two Tube
> Portable Works Speaker", which includes the design of a folding horn for the
> loudspeaker.
> 
> Any help in identifying this would be appreciated.
> 
> 73 de NB1I
> John Levreault
> 
> 

------------------------------

Date: Fri, 22 Nov 1996 09:18:44 +0000
From: [email-masked] (Randy Pelt)
To: [email-masked]
Subject: 80 Meter Transceiver
Message-ID: <v01540b02aebb1fc049b6@[198.82.152.40]>

There is a real nifty qrp tube transceiver for 80 Meters in the July 1973
QST.  It will put out up to 10 watts.  Check it out!

72/3

                                      ___  _________
Ranson J. Pelt                        \  \/ __   __/
[email-masked]                            \   / /  /
QST de w4wyt      Semper Fi             \_/ /__/
    ex-nz4i

------------------------------

Date: Fri, 22 Nov 1996 11:07:03 -0500 (EST)
From: [email-masked]
To: [email-masked], [email-masked]
Cc: [email-masked] ()
Subject: Duelling Hartleys it were on the BA/GB QRG
Message-ID: <[email-masked]>

Had great fun duelling the 210 Grandma Hartley at 1 watt output with a
15 watt 211 Hartley of WB2ABQ(?).  That 50 watt bottle sounded sweeter'n
apple pie.  Alas, we had a fair wind/rain storm with tons of QRN here
last night, and the antenna was swinging highly in the wind.  Thus ol'
Grandma Hartley was a'wobblin' on 3579.545 +- 500hz, or so, as the antenna
swung back and forth.  Oh, well, at least it sounded like a real Hartley
then.....  The wx man sez the whole of North America will be pretty cool
tonight and the weekend, so methinks the band will be up again.  Someone
mentioned there was some sort of CW contest on, but that should probably
not affect the BA/GB QRG.  Perhaps it will be another fine weekend for
the BA/GB folks and we will get a bunch o' grand ol' ether burners on
watch aboard the ol' crackle an' din o' 80M tonight and Sat. nite.
Last night Conard's fine 6Y6 puffer was doing a grand job and K3KC's(?)
husky Viking II was knockin' de ol' tin cans off me noggin.  So, as some
crusty ol' feller once said.....``grapples ye up yer tin cans atop yer
noggins, fires ye up yer fine glowbottles, an' readys ye yer keys at
the fore... it be a fine BA/GB nite on watch, tonight!''

See ya there!

73/ZUT DE NA4G/Bob UP

------------------------------

End of GLOWBUGS Digest 360
**************************