Subject: GLOWBUGS digest 315

From: [email-masked]
Date: Mon, 7 Oct 1996 15:51:02 -0500 (CDT)

GLOWBUGS Digest 315

Topics covered in this issue include:

  1) Handbook Power Transformer Leads ID
	by [email-masked]
  2) Re: glass qrp
	by "Brian Carling" <[email-masked]>
  3) Regenerative Design
	by [email-masked] (Forrest B. Snyder Jr)
  4) Re: Re^2: Temperature Control and Thermal Drifts
	by [email-masked]
  5) Re: Re^2: Temperature Control and Thermal Drifts
	by [email-masked] (Steve Linscott)
  6) Re: Regenerative Design
	by [email-masked]
  7) BA/GB net frolics this weekend
	by [email-masked]
  8) WTB 6L6's
	by Guy Dragoo <[email-masked]>
  9) BA/GB 1 Watte Challenge at Highe Midnighte
	by [email-masked]
 10) Re: glass qrp
	by Jeffrey Herman <[email-masked]>
 11) Re: Regenerative Design
	by "Claton Cadmus" <[email-masked]>
 12) Re: WTB 6L6's
	by "Brian Carling" <[email-masked]>

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

Date: Sun, 6 Oct 1996 19:07:20 -0400
From: [email-masked]
To: [email-masked]
Subject: Handbook Power Transformer Leads ID
Message-ID: <[email-masked]>

In response to a request for more information on identifying surplus
transformers, here are the page numbers from the 1996 ARRL Handbook with more
information of transformers as well as tubes.

Page 11.3 "How to evaluate unmarked transformers."

Page 24.7, Table 24.12 Power transformer lead color codes

Page 24.28-29 Transmitting tube specifications.

Page 24.30 EIA standard tube pin-outs.

The handbook has good basic information on everything from basic tube and
transistor receivers and transmitters to information on basic circuit
operation and design. This book is still my first recommendation for any new
ham asking about a good book to buy to learn more about this hobby. I
recently bought a 200 page 6" x 8" industry reference for nearly twice the
$38 the '96 Handbook costs, and consider it a bargain compared to some of the
standard references I have to update every one to three years. Either support
your local amateur radio retail outlet and buy it there or order one from the
ARRL. It will be the best $38 you'll spend.

Darrel, WD6BOR

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

Date: Mon, 7 Oct 1996 04:17:30 +0000
From: "Brian Carling" <[email-masked]>
To: [email-masked]
Subject: Re: glass qrp
Message-ID: <[email-masked]>

There has been a severe problem recently with many LISTS on the 
Internet.

APparently someone found a way to DISABLE a lot of te lists.
They are just now beginning to get going again.
This has been reported to me from various people on various lists. I 
noticed most of the lists I was on had a problem this past weekend, 
where the message flow either stopped completely (like this one) or 
dwindled to a trickle compared to the normal rate.

I am sending this as a test. You MIGHT need to advise the recipients 
to get re-subscribed, or to look at the list and see if the addresses 
have all disappeared.

This message will also serve as a test to see whether it appears on 
glowbugs or not.

I see no new messages here in the past 24 hours or so.

Best regards - Bry
Brian Carling in Gaithersburg, Maryland, USA
[email-masked]
http://www.mnsinc.com/bry/

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

Date: Mon, 7 Oct 96 09:27:12 -0400
From: [email-masked] (Forrest B. Snyder Jr)
To: [email-masked], [email-masked]
Subject: Regenerative Design
Message-ID: <[email-masked]>

Good Morning Bob et. al.

Thanks for the info on putting together a selective toob type regen.  Since 
that posting, I've been poring over various old (Doerle) and more modern regen 
schematics and info in ARRL and other pubs. I have a couple of questions which 
I hope you and the other members of the list can answer.

1.  Older schematics (Doerle) use three coils in the detector circuit: an 
antenna link, an input tank, and a tickler.  More modern schematics use a 
single coil with taps for the antenna and tickler. (ARRL How to Become a Radio 
Amateur ca. 1959). I can see that the tapped coil design might be easier to 
construct, but does either design offer distinct advantages/disadvantages of 
these designs in terms of sensitivity, selectivity, and stability (S3)?

2.  Regens are noted for radiating signal from the oscillating detector back 
to the antenna. Is there any way to eliminate this short of adding a tuned RF 
section in front of the detector? If not, is there any way to keep the amount 
of re-radiated signal down where it will offend no one?

3.  How will the use of a tuned RF section in front of the detector affect 
receiver S3?

4.  Some designs use a variable capacitor to control regeneration.  Others use 
a variable resistor and control regeneration by varying detector plate voltage 
- -- again, simpler and more repeatable construction.  Both methods are 
mentioned in older ARRL handbooks.  Are there any S3 performance advantages to 
either method? 

5. Svetlana makes a nice little 6BM8 dual pack triode/pentode, and an equally 
neat 6AS7 dual triode -- both intended for high performance audio service. 
Spec sheets are available on the net at www.svetlana.com. Has anyone build a 
receiver around either of these tubes?  (If not, I might like to try! -- It 
looks like they're just made to power a high-perfomance glow-bug receiver.)

Thanks in advance for the discussion.  If there is enough interest, I'll be 
more than happy to archive the information and forward the archive to anyone 
with an interest.

Forrest B. Snyder, Jr.
N4UTY [email-masked]
"Radio in the rough!"
BC-348-R
Johnson Adventurer (Rock bound!) and a straight key
40 M Center-fed Zepp between two trees

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

Date: Mon, 7 Oct 1996 09:59:34 -0400 (EDT)
From: [email-masked]
To: [email-masked]
Cc: [email-masked] (), [email-masked]
Subject: Re: Re^2: Temperature Control and Thermal Drifts
Message-ID: <[email-masked]>

Wonderful discussion, Barry.  I missed those thermostats at Shelby, but
may be able to make off with one of the XYL's old hairburners.  Hopefully,
the glowbuggites can see that there are both ivory tower and seat of the
pants approaches to glowbugging vfos and that many directions can be taken
to reach the same pinnacle of delight (glowbugging).  I tend to be a seat
of the pants type (why else play with Hartleys, etc), away from the test
tubes.  All it takes is a bit o' grey matter pondering, some occasional
high level calculations, some occasional rules de thumb, a well stocked
OT library, and a pile o' parts to play with.

Ahh, the true spirit of glowbugging!

73/ZUT DE NA4G/BOB UP

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

Date: Mon, 7 Oct 1996 09:20:04 -0500 (CDT)
From: [email-masked] (Steve Linscott)
To: [email-masked]
Cc: [email-masked]
Subject: Re: Re^2: Temperature Control and Thermal Drifts
Message-ID: <v01540b03ae7e76af75db@[128.42.14.170]>

Bob and the gang:

 You guys are bringing back memories!   During the Apollo program, I was an
IBMer at Mission Control in Houston.  One of our 6 IBM 360/Model 75's lived
in a separate building, and performed the function of simulating the "real
world".  It pretended to be the world-wide data network, and fed input to
the Real Time Computer Complex.  It had a time standard in a temperature
controlled oven.  The oven failed, and since it was a custom job, delivery
of a replacement was going to take 6 months.  An enterprising engineer
stuck a 40 watt light bulb in the oven, and we were up and running.  A few
months later a Lunar landing simulation started going awry, and we
discovered that the light bulb had burned out!  It was replaced, and 15
million dollars worth of computer equipment was happily simulating again!

                                         73 de W5EGP

                                                 - Steve -

******************************************************************************
*     Steve Linscott        Divisional Consultant        Natural Sciences    *
*   Rice University     6100 South Main Street    Houston, Texas 77005-1892  *
*    Phone: (713) 527-4985   FAX: (713) 527-6099   Email: [email-masked]   *
******************************************************************************

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

Date: Mon, 7 Oct 1996 11:13:17 -0400 (EDT)
From: [email-masked]
To: [email-masked] (Forrest B. Snyder Jr)
Cc: [email-masked] (), [email-masked]
Subject: Re: Regenerative Design
Message-ID: <[email-masked]>

> 
> Good Morning Bob et. al.
> 
> Thanks for the info on putting together a selective toob type regen.  Since 
> that posting, I've been poring over various old (Doerle) and more modern 
> regen schematics and info in ARRL and other pubs. I have a couple of
> questions which I hope you and the other members of the list can answer.
> 
> 1.  Older schematics (Doerle) use three coils in the detector circuit: an 
> antenna link, an input tank, and a tickler.  More modern schematics use a 
> single coil with taps for the antenna and tickler. (ARRL How to Become a
> Radio Amateur ca. 1959). I can see that the tapped coil design might be
> easier to construct, but does either design offer distinct advantages/
> disadvangages of these designs in terms of sensitivity, selectivity,
> and stability (S3)?

Generally, a single coil design will tend to be loaded down, and less
selective, unless you use extremely light coupling into the grid tank.

Generally, a triple winding coil design or a primary/secondary design
will offer better selectivity, if properly done, than a single coil
design.

Generally, a non-tickler, single coil design is used with higher plate
voltages and multigrid tubes.

Generally a tickler system is used with lower plate voltages and triode
tubes, although that is not an absolute.

The use of more than a single winding coil will increase the complexity
of the design, compared to a single winding tapped coil.  Most of the
later designs were for ``simple'' receivers and not optimized receivers.

In a ``best of all possible worlds'' design, I would opt for a system
that had a) a fully tunable primary circuit, b) a loosely, but variably
coupled secondary circuit, and c) a variable tickler circuit with proper
throttle condenser fine control.  Since I prefer to run at lower plate
voltages, the use of a resistive system is less effective than a real
tickler/throttle condenser system, and it may require more fiddling to
get taps and biasing resistor networks set correctly.

> 2.  Regens are noted for radiating signal from the oscillating detector back 
> to the antenna. Is there any way to eliminate this short of adding a tuned RF 
> section in front of the detector? If not, is there any way to keep the amount 
> of re-radiated signal down where it will offend no one?

All regens will radiate unless they have an RF stage in front of the detector.
Even then, they might still be heard in the same shack, without good shielding.

But, it should be noted that the level of radiation is quite low on average,
and very low on a tickler system with loose coupling and a plate voltage of
less that 50 volts.

Example:  I use a single tube baby regen sometimes, for playing with the
locals, and it has a 36 volt triode detector using a 1 turn link at the cold
end of the tank coil.  When on the edge of oscillation, it will radiate a
signal, when hooked up to a full sized antenna, that can be heard by a
neighbor ham with a big antenna farm and hot Ten-Tec gear, at a range
of about 500 meters.  Another ham, running almost identical gear and antenna
system, about 2000 meters away, cannot hear the regenerator, at all, yet
we QSO regularly on a companion Hartley running 96 volts on the plate
at about 450 mw output.  It would appear that the few microwatts out
from the regen detector is not of much significance, even locally, until
one gets very close by.

The best way to keep the detector output out of the antenna is LOOSE COUPLING.
Keep the coupling loose, the plate voltages low, and the detector on the
ragged edge of oscillation.  That will minimize any potential local
interference.  It will also increase selectivity, greatly.

> 3.  How will the use of a tuned RF section in front of the detector affect 
> receiver S3?

The RF stage will increase immunity to close by signals to some extent by
providing some isolation.  It will not materially affect sensitivity, 
selectivity, or stability on a proper detector.  It will, by means of the
isolation, stabilize a poor detector by providing it a constant loading,
and increase the relative sensitivity by providing some gain.  On a proper
detector, that is already well shielded, well uncoupled, and stable, the
effect is nil.

> 4.  Some designs use a variable capacitor to control regeneration.
> Others use a variable resistor and control regeneration by varying detector
> plate voltage --- again, simpler and more repeatable construction.
> Both methods are mentioned in older ARRL handbooks.  Are there any S3
> performance advantages to either method? 

It usually depends upon one of two things.  First, is the plate voltage
high (greater than 50 volts) or low (less than 50 volts).  Second, is the
noise of the resistor biasing system acceptable or not.  In the case of plate
voltages, I usually use lower voltages, and at lower voltages the control is
not good enough in my hands to warrant resistor control.  A throttle
condenser is much smoother in action at lower voltages than the resistor
control.  In the case of noise generation, the potentiometer methods all
will generate significant detector noise, even with good bypassing and
isolation by means of chokes and bypassing networks (resistor/capacitor
bypass networks).  The throttle condenser method is totally noiseless
unless the shaft on the capacitor is grinding.  There is no real sensitivity,
selectivity, or stability factor involved here, just ease of setting the
regeneration and noise generation.

The RAL is the epitome of regen receiver designs.  It uses a rather high
plate voltage of 180 volts, dropped to 90 volts on the detector by a resistor
string or by an external voltage regulated line on the original power supply.
It uses a rather fine resistor control of the 6D6 detector tube, but also
uses good bypassing and isolation to prevent detector problems.  Even
then, you can hear the regen control noise, very slightly.  None of my
throttle condenser receivers have any such noise from the regen control.
That is not usually a problem, though, since the regeneration control
is usually set once on the bottom of a band and left there.  If you like
to ride the regeneration control for absolute maximum selectivity and
sensitivity, then the noise in the resistor is a small bit of hassle.
In this case the throttle condenser is much to be preferred.

One can combine a resistor control to set the relative regen value and
then fine tune the regeneration with a throttle condenser.  I do that
but use a variable tickler and throttle condenser to accomplish the task,
although a resistor control and throttle condenser would work equally well.

> 5. Svetlana makes a nice little 6BM8 dual pack triode/pentode, and an equally 
> neat 6AS7 dual triode -- both intended for high performance audio service. 
> Spec sheets are available on the net at www.svetlana.com. Has anyone build a 
> receiver around either of these tubes?  (If not, I might like to try! -- It 
> looks like they're just made to power a high-perfomance glow-bug receiver.)

They should all work fine.  I have used the 6AS7 as a detector and it works
just like the 6SN7, but as a more powerful detector.  It also makes a fine
Hartley oscillator tube when both sections are paralled.

The 6AS7 is plugin compatible with the 6SL7/6SN7/6080/6336, etc., but rated
at about 7 watts in Hartley use.  It is a low voltage tube and probably will
work best on less than 90 volts on the plates.  It can run 350 volts at
200ma if you push a little and the biasing is correct ---- ouch.
It will make a fine Hartley oscillator or detector on as little as 12 volts
on the plates.
 
Although multitube bottles are very workable in regen designs, I tend to
like to keep the detector separate from the audio sections, so would opt
for separate tubes.  Also, my fingers and 100 watt soldering gun don't
take easily to mini tubes and mini tube sockets.  I much prefer octal
or larger basing.

For a triode, I would prefer something like a 27, or a 76, or a 6J5.
You can wire multiple tubes in one bottle together, as one triode.
They are also good for transformer coupled audio.  Generally, only one
audio stage is needed if transformer coupled, but it is sometimes of
benefit to have two audio stages if running lower plate voltages such
as below 50 volts.  Also, the use of audio transformers is of goodly
benefit if they are tuned with proper capacitors on the inputs and outputs
so that a very selective audio filter system is had, tuned to whatever is
your favorite headfone frequency.  

For tetrode/pentode/beam tubes, anything up to an 807 has worked in my
hands as a regenerative detector.  Steve, in Texas made a good working
regen set out of a single 833 tube.....(Steve, you still listening?). 
I made a very good regen receiver out of a pair of 6V6's running 12 volts
on the plates using a 10h impedance coupling choke and an audio output
from an old tube radio to 8 ohm fones.

Hmmmmm, I gots this 'ere 849 tube thats me wan't ta make sumthin' outta........

> Thanks in advance for the discussion.  If there is enough interest, I'll be 
> more than happy to archive the information and forward the archive to anyone 
> with an interest.

It would probably be of interest to folks if someone were to put all this
muckety muck together into one file.

> Forrest B. Snyder, Jr.
> N4UTY [email-masked]
> "Radio in the rough!"
> BC-348-R
> Johnson Adventurer (Rock bound!) and a straight key
> 40 M Center-fed Zepp between two trees

73/ZUT DE NA4G/Bob UP

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

Date: Mon, 7 Oct 1996 12:03:45 -0400 (EDT)
From: [email-masked]
To: [email-masked], [email-masked]
Cc: [email-masked] ()
Subject: BA/GB net frolics this weekend
Message-ID: <[email-masked]>

Well, Friday was a bit dead, but the usual crew was there from east of
the Rockies, and WS4S kept the brass hot until well past midnight.
That was one of the longest CW QSO's I have had in a great while --- 3 hours
of hot 'n  heavy BA discussions.  The contacts on the bug were warm!
Saturday was much better, with a good cold snap heading south, and a lot
of folks were there, some not heard since last year.  Grandma Hartley
was up and running at 2 watts and made a few QSO's.  So, glad all you
BA/GB folks wats burned them thar ether holes this fine weekend were able
to join in.  The DEEX were also up, since EU stns were 579 on 80, no less.
160 was fair, but I need to get the long wire up again for that.  Hurrycane
Fran knocked that down.  Will look fer another goodly crew aboard the watch
again, tonght.  73/ZUT DE NA4G/Bob UP

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

Date: Mon, 7 Oct 1996 12:17:36 -0500
From: Guy Dragoo <[email-masked]>
To: "'Multiple recipients of list (Boatanchors)'"
Subject: WTB 6L6's
Message-ID: <[email-masked]>

Hi all,
I'm looking for some 6L6's for a homebrew xmitter.
Pulls are fine as long as they test out OK.  Hollar with
ur pricing and quantity available as I will probably need
a few extra for that inevitable mistake or two :-(
thanks and 73
Guy Dragoo AC5HL

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

Date: Mon, 7 Oct 1996 13:59:43 -0400 (EDT)
From: [email-masked]
To: [email-masked]
Cc: [email-masked] ()
Subject: BA/GB 1 Watte Challenge at Highe Midnighte
Message-ID: <[email-masked]>

For funzies, I challenge all ye fine Glowbuggites to cobble something together
fer duelling at under 1 watt at ``High Noon'' er make that Highe Midnighte
(0400Z) on the 80M TV rock frequency of 3579R545KHZ.  Anything be accepted,
as long as it has hot/hollow/gaseous emanations into the ether and glows
somewhat in the dark --- spark sets not allowed, currently.....(:+{{.....
West coasters can try 0700Z fer their round.  Middle westerners can join
the east/west o' de continental divide as they sees fits.

Ol' Grandma Hartley, the ugliest thing since sliced bread, albeit a fine
tempered grand dame, seemed to do well on 2 wattes de exhalations this
weekend, so mebbee there is hope for a peanut whistle, after all!  Her
youngest harmonic, Lil' Baby-Cakes Hartley, may be sneaking a peek in 
the shack, tonight, to see howse it be done......(:+}}....  Lil' Baby-Cakes
only has a mittlin DX o' 100 miles so far, an' needs some careful larnin'.
An' she aint been properly introduced to open wire line kiddies yet.

So, fer de rest o' dis 'ere week, keeps High Midnighte open fer peanut
whistles, in the ether..... in additions ta yer standard BA/GB funzies.....

73/ZUT DE NA4G/Bob UP

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

Date: 	Mon, 7 Oct 1996 08:42:00 -1000
From: Jeffrey Herman <[email-masked]>
To: Brian Carling <[email-masked]>
Subject: Re: glass qrp
Message-ID: <Pine.GSO.3.93.961007083937.27725C-100000@uhunix3>

Brian: There's nothing wrong with the GB list. Unlike QRP-L, TopBand,
BA, TenTen, et al, the activity on GB comes in spurts. An entire
week can go by and no one might have anything to write about. That's
why it's a good idea to also sub to BA - that list is always active.

7.3W,
Jeff KH2PZ / KH6

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

Date: Mon, 7 Oct 1996 13:49:20 -0500
From: "Claton Cadmus" <[email-masked]>
To: "Multiple recipients of list" <[email-masked]>
Subject: Re: Regenerative Design
Message-ID: <[email-masked]>

> It would probably be of interest to folks if someone were to put all
this
> muckety muck together into one file.

It sure would be if interest to me.  I missed most of the beginning of the
thread as I've recently joined on.

Presently, I'm collecting parts to build/model a 1935~ Home-brew Ham
Station.  I've looked at some designs in old ARRL Handbooks and I'm
considering a Regen.  This rig won't be a replica, just model the style. 
Breadboard old tubes and parts etc.  But I'm all for using newer ideas to
improve the performance.  I even considered a direct conversion design
receiver, but I think getting enough gain would be difficult.

Any suggestions welcomed.

Claton Cadmus			|73 de KA0GKC
Application Technologies Inc.	|ARRL, QRP-ARCI, NorCal
Ph.  (612)926-8886		|ARCC, MNQRP&HB Society
Fax  (612)926-8545 		[email-masked]	
E-mail  [email-masked]	|ka0gkc@wb0gdb.#stp.mn.us

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

Date: Mon, 7 Oct 1996 13:40:52 +0000
From: "Brian Carling" <[email-masked]>
To: Guy Dragoo <[email-masked]>, [email-masked]
Subject: Re: WTB 6L6's
Message-ID: <[email-masked]>

I'm also looking for some.
I have one here, and no idea if it is any good.

Let me know please!

Hey, looks like glowbugs is working nicely again now!

Bry AF4K

> Date:          Mon, 7 Oct 1996 12:23:29 -0500 (CDT)
> Reply-to:      [email-masked]
> From:          Guy Dragoo <[email-masked]>
> To:            Multiple recipients of list <[email-masked]>
> Subject:       WTB 6L6's

> Hi all,
> I'm looking for some 6L6's for a homebrew xmitter.
> Pulls are fine as long as they test out OK.  Hollar with
> ur pricing and quantity available as I will probably need
> a few extra for that inevitable mistake or two :-(
> thanks and 73
> Guy Dragoo AC5HL
> 
> 
> 
Brian Carling in Gaithersburg, Maryland, USA
[email-masked]
http://www.mnsinc.com/bry/

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

End of GLOWBUGS Digest 315
**************************