Subject: GLOWBUGS digest 332

From: [email-masked]
Date: Sat, 26 Oct 1996 11:12:33 -0500 (CDT)

GLOWBUGS Digest 332

Topics covered in this issue include:

  1) Re: Regen Plans
	by [email-masked] (Jeff Duntemann)
  2) Re: tube bank
	by [email-masked] (Jim Haynes)
  3) Re: Regen Plans
	by Steve Byan <[email-masked]>
  4) Re: Regen action report
	by [email-masked]
  5) Re: Regen Plans
	by [email-masked] (John Levreault)
  6) Re: noise limiter help
	by "Brian Carling" <[email-masked]>
  7) 6L6 Xmtr update...
	by Gordon Gekko <[email-masked]>
  8) Re: TUBE BANK(s) Idea!
	by [email-masked] (Richard H. Arland)
  9) Re: Glowbugs admin ... please read.
	by [email-masked]
 10) Hammarlund Coil Forms
	by [email-masked]
 11) Re: TUBE BANK(s) Idea!
	by [email-masked] (John Levreault)

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

Date: Fri, 25 Oct 1996 09:16:16 -0700
From: [email-masked] (Jeff Duntemann)
To: [email-masked]
Cc: [email-masked]
Subject: Re: Regen Plans
Message-ID: <[email-masked]>

At 09:32 AM 10/25/96 -0500, you wrote:
>For those who are searching for regen projects I might suggest looking in
your older
>tube manuals. I am looking in the circuit section of my RCA RC-16(1950)
Receiving
>Tube Manual and find three interesting circuits numbered 16-5, 16-6, and
16-7. The
>first is a superregerative receiver with it's own power supply and using a
6C4 for
>a detector. It has a two tube audio stage driving a speaker. With the 6X4
power supply
>it's a four tuber. 

>Are there other examples in tube manuals you have? Or are these designs
really pretty
>ho-hum?

I built the 2-tube audio section from that RCA 6C4 superregen into a couple
of different receivers, and it works beautifully, capable of ear-splitting
volume.  It's a great proven "building block" for homebrew designs of
whatever architecture.  You might have to tweak it a little to tie the
diodes in the first audio envelope back into the rest of a superhet, but for
a regen it stands alone nicely without modifications.

I'll be happy to send a copy of the page with that circuit to anyone who
sends me an 32c business-size SASE.

--73--

--Jeff Duntemann KG7JF
The Coriolis Group, Inc.
7339 E. Acoma Drive, Suite 7
Scottsdale AZ 85260

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

Date: Fri, 25 Oct 1996 10:04:45 -0700
From: [email-masked] (Jim Haynes)
To: [email-masked]
Subject: Re: tube bank
Message-ID: <[email-masked]>

There was something in QST in the last couple of months about a guy in
San Diego who has a tube bank for mail order - tubes are free but you pay
for the shipping.  Then there's a guy locally who was given a large stash
of tubes by some ham who retired and moved, so we have a local tube bank.

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

Date: Fri, 25 Oct 1996 13:51:08 -0400
From: Steve Byan <[email-masked]>
To: [email-masked]
Cc: [email-masked]
Subject: Re: Regen Plans
Message-ID: <v03007808ae96abc8e03f@[140.243.30.128]>

>third one is a little battery set with a 1U4 RF amp, a 1U4 detector,
>and a 3V4 power amp also driving a speaker. It wants 90 volts B+ and
>1.4 volts to the filaments.

That circuit is also in the reprint of the 1959 RCA Receiving Tube Handbook
available from Antique Electronic Supply. I've had my eye on it for a while
and have been collecting parts for it at the fleas. I have a real weakness
for portable battery sets since I started SWLing on a RCA Strato-World
portable. The hardest part was finding a dual 140 pF air-variable cap; I
came across some NOS Hammarlund HCD-140-M's that I snarfed up for this
project. RCA lists the coils as "standard 6-pin coil set for 140 pF tuning
cap" with no winding data, so I figure I'll be doing a bit of
experimentation while winding the coils.

I've been debating whether to rely on mechanical bandspread from the
dual-ratio (6:1 and 36:1) Jackson Bros dial drive I have squirreled away or
to use a 35 pF dual variable cap for electrical bandspread. I'm interested
in shortwave listening, mostly below 7 MHz, but would like general coverage
too. Perhaps I'll make up a couple of bandspread coil sets for the 60, 90,
and 120 meter SWBC bands in addition to the general coverage coil sets.

Regards,
-Steve

Steve Byan                                  internet: [email-masked]
Hitachi Computer Products (America), Inc.
1601 Trapelo Road                              phone: (617) 890-0444
Waltham, MA 02154                                FAX: (617) 890-4998

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

Date: Fri, 25 Oct 1996 14:32:48 -0400 (EDT)
From: [email-masked]
To: [email-masked] (Conard Murray)
Cc: [email-masked] (), [email-masked]
Subject: Re: Regen action report
Message-ID: <[email-masked]>

Conard.... you raise some good points for discussion, so I will pass it
to the list.

> Well, my first regen broke into oscillation at approx 12:45 last night.

What a warm fuzzy, fer sure.....

> I was having problems with no oscillation. I fiddled with the tickler
> for 45 mins but was sure I had that part right.  I tacked a dual section
> 365 uuf across the throttle in desperation and (!whammo!), it took off.

Generally a tickler should be about 10-20 percent of the main coil, max
on a triode and maybe only 5-10 percent on a pentode or tetrode tube.
Use as little tickler as will regenerate.  Use a good RF choke at the
throttle condenser to make sure the condenser gets the control.
My usual throttle is a 150 uuf minimum, but I will use a 365 if I have
a small spare from a bcst set.  To set the tickler turns, put the throttle
control about half way at the expected plate voltage and then shunt the
throttle with a 0.001 (1000pf) condenser to give you a forced oscillation.
If that works, then all is well.  If that does not work, check the wiring
for a reversed tickler (Tuska's reversed tickler neutrodyne circuit).
A reversed tickler degenerates rather than regenerates.  Also check for
a good grid leak and grid cap.  Usually the reversed tickler is the culprit.
Once the number of tickler turns are set, dope the coil to make it permanent
and you are all set.  Usual dope is ladies clear fingernail polish or
Duco household cement.  Real coil dope is scarce these days.  AES may
have some.

> I can actually hear signals with it.

Sensitive little muthers, ain't they.....(:+}}.....

> I had a real lashup for a power supply as I was using my 500 volt general
> purpose plate supply with a variac holding it down to 45 volts.  Lotsa 
> lotsa huuuuuuummmmmmm, but still could hear stuff. I see what you meant
> about leaving room for mods, as these regen sets are something to fool with.

Always use a battery supply if possible on regens, or and ac supply with a
VERY WELL filtered output. 

Yes, room to play is always welcome on a regen, and it helps to prevent
stray couplings that reduce Q and selectivity.

> I was having problems with the throttle pulling the frequency pretty bad,
> so I took off about 1/3 of the tickler winding and that cured most of the
> pulling effect as well as making the control better. 

Usually, that indicates a poor feedback path.  Most of the time that is
due to a poor telephones bypass cap on a single tuber or a poor RF choke
in the plate circuit of the detector of a multi-tube circuit.

Always use the minimal tickler required to get good regeneration.  Those
who have a variometer coil can set the variometer to just induce regeneration
with the throttle condenser set about half way, and that makes regeneration
as smooth as silk.

When the regeneration control is good, you should barely be able to hear
it squeeze up into oscillation, and it should have a slight plop coming
out of regeneration.  If it plops with a hard sound both into and out
of regeneration, you have too sensitive a throttle (too much tickler).

> Also found out about some of the effects of the grid-leak capacitance.
> I am using your 10 Meg and 10 uuf values, but I had tacked a  680 uuf
> across the leak trying to get it to oscillate. The 680 uuf value was
> from another schematic for a SWL rx and with it the set soounded about
> right for AM. I snipped the 680 out and you could really hear the
> selectivity narrow down. 

Typically, at longwaves, a 500pf cap was used.  Typically at medium waves,
a 250 pf cap was used.  Typically at short waves, a 100pf cap was used.
For my use, I prefer the minimum grid cap that will work, and at HF opt
for the 10pf cap with a high value grid leak.  In my hands it works better.
It also increases the selectivity, as you found out.

I prefer the highest grid leak value that I have handy.  Usually that is
10 megs, but sometimes, if the grid cap is leaky, you don't even need a
grid leak at all.   There is a point at which the too high leak value
will cause the grid to freeze up and not leak its charge with a sufficiently
high audio time constant.  Beyond that leak value it just won't work.
My guess is that that value is practically around 100 meg ohms.

> I gotta work on the tuning rate also. I am uning a 5-40 uuf variable,
> but I think I will swap out to a better 100 uuf unit and pad it out to
> cover the band.  I was thinking of using band-set caps and such, but I
> want the stability more than I want to be able to slip out of the ham
> bands. 

A 100uf unit will go way beyond the bands.   Your 5-40 uuf should cover
all of 80 meters.  I use a single plate to cover just the CW portion of
choice (3500-3600khz).  Usually little band set cap is required, although
I have been known to hang a 25pf variable to adjust the band edges to where
they hit the 0 or 100 mark exactly on a velvet vernier.  If you have more
than about 25pf of padder, then the effective range of the tuning cap is
somewhat less, but a 40pf cap should still cover all of 80 meters.

> A friend just brought me a sack with 20 half-shot 9 Volt batteries so
> will try that later for a plate supply. He also has a large supply of
> retired 6 Volt 2 Amp/hour batteries that I can raid. That will be even
> better! 

The 9 volters are a waste in my book, except for emergency lashup.
The 2ah sealed lead acids, on the other hand, make an excellent battery
power supply if you can muster up 36 or 48 volts worth.

> Sorry to go on for so long ..... 

That is what the list is about, amongst other things, right?

> Yours regenerative-ly

Hey, that is a fine way to be known...... regeneratively!

> ZUT!
> de Conard ws4s
> Conard Murray  WS4S  NNN0UTN   [email-masked]
> 217 Dyer Avenue                BA/GB net 1802.5/3579.5/7050 KHz
> Cookeville, Tn  38501
> 615-526-4093
>           - LICENSED ONLY TO EXTENT INDICATED ON CARTON -

Typical RCA label there, fer sure.....(:+}}.....

73/ZUT DE NA4G/Bob UP

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

Date: Fri, 25 Oct 1996 14:29:59 -0400 (EDT)
From: [email-masked] (John Levreault)
To: [email-masked]
Cc: [email-masked]
Subject: Re: Regen Plans
Message-ID: <[email-masked]>

>For those who are searching for regen projects I might suggest looking in
your older
>tube manuals. I am looking in the circuit section of my RCA RC-16(1950)
Receiving
>Tube Manual and find three interesting circuits numbered 16-5, 16-6, and
16-7. The
>first is a superregerative receiver with it's own power supply and using a
6C4 for
>a detector. It has a two tube audio stage driving a speaker. With the 6X4
power supply
>it's a four tuber. The next page has a ac-operated regen, for those who
have a power
>supply, employing a 6SK7 in both an RF apm stage and as a detector. It also
has an
>audio section with a voltage amp amd a 6K6 power amp stage driving a
speaker. The
>third one is a little battery set with a 1U4 RF amp, a 1U4 detector, and a
3V4 power
>amp also driving a speaker. It wants 90 volts B+ and 1.4 volts to the
filiments.
>
>These circuits are claimed to be well though out and conservative
designs(at least RCA
>thought so) but RCA thoughtfully leaves the construction details to the
reader. They
>look sound to me and perhaps have enough clues to the coil winding
requirements to
>be build-able without too much trouble. Might be worth looking at.
>
>Are there other examples in tube manuals you have? Or are these designs
really pretty
>ho-hum?
>Regards,
>John Heck, KC8ETS
>Dayton, Ohio
>[email-masked]

Yes, they are pretty ho-hum, but they may actually have been used in real
products.

One example of this is the RIAA-phono preamplifier that appears as Figure
29-16 in my RCA Receiving Tube Manual, RC-29. This design has been used by
number of manufacturers when they needed a phono stage in their hi-fi
preamps and integrated amps. It's a simple but very good circuit with quite
good sound, although its performance is highly dependent on the component
quality and power supply. There's a guy in PA (Handmade Electronics) who's
presently offering a kit based on this design, if anyone out there is
interested in tube audio in addition to this here glowbugness.

All of the circuits in the RCA manual were apparently built and tested by
their engineers. Personally, I wouldn't hesitate trying to duplicate one of
those designs, although parts gathering may be a problem.

73 de NB1I
John Levreault

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

Date: Fri, 25 Oct 1996 12:18:55 +0000
From: "Brian Carling" <[email-masked]>
To: [email-masked]
Subject: Re: noise limiter help
Message-ID: <[email-masked]>

HEY! It's a reply from AF4K!
On 25 Oct 96, Roy Morgan wrote:
> I'm all set
> for rock-bound ether poking on the ole QRG.  Now, if we could only
> get W1AW to go to bed earlier ... 

I wish that they would realize how many people want to use 3579, and 
then QSY the W1AW signal up a couple!

73 from Radio AF4K / G3XLQ in Gaithersburg, MD USA
[email-masked]
*** See the great ham radio resources at: 
http://www.mnsinc.com/bry/

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

Date: Fri, 25 Oct 1996 12:46:16 -0700 (PDT)
From: Gordon Gekko <[email-masked]>
To: [email-masked]
Subject: 6L6 Xmtr update...
Message-ID: <[email-masked]>

Hi everyone!

First off, I would like to express many thanks to Guy Dragoo, Mr. Dunteman, and
all of the others who have so kindly sent snail-mail schematics of 6L6
transmitters.
I think I now have a schematic of all the major oscillator designs and output
circuits that were commonly employed from the 1930's to present.  I will be
scanning
these diagrams this week on a page scanner and I will then post a list of
what all
I have to the group.  Any interested parties can then email me what they
want and
I'll send it on it's way.  I have found that they hold up much better if kept in
the native .BMP format my scanner produces.  I can make .JPG's but they tend
to lose
out a little on horizontal resolution (for some reason, vertical isn't
affected). The
list should be ready in a few days or so.

I have just completed my little rig (Guy Dragoo's schematic won out) and it
works 
great with either rocks or my HG10 VFO (but that's cheating!).  With the
power supply
I am using and a 6V6 in the socket, I get about 8 solid watts into a dummy
load.  The
OD3 keeps me chirp free.  Nice little xmtr!

Now I am on the prowl for a regen project.  I have one neat design from the 1954
'How to Become a Radio Amateur' that I will probably tackle.  Seems to have
manageable
coil designs that can be duplicated without using non-existent B&W coil stock.

On the boatanchor front, I just picked up a DX40 in very good condition for
$35!  I hope
to have it on the air this weekend.  I also just got a National NC66
portable in kinda
sad shape (great looks - just needs new caps and glowplugs).  Very unique
old receiver.
The coverage is 200KC to 23MC (I don't think it tunes Hertz at all) - what
an odd
range.  It is intended for portable use, and has a battery compartment for
some flavor
of B battery, plus an internal AC supply and telescope whip antenna.  This
will be the
companion for the DX40 after I restore it.  Not a bad project for only $20.
It's 
cosmetically very good, so well worth the money.  It's a long shot, but if
anyone has
a schematic for the NC66 or the DX40, I would glady pay the expenses to get
a copy or
swap hardcopy of the 6L6 rigs.

Ok, ok, I'll stop rambling!

Thanks again for the 6L6 stuff.

73's

Dave (aka Gordon Gekko)

WB7AWK
Tacoma, WA

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

Date: Fri, 25 Oct 1996 21:13:17 PST
From: [email-masked] (Richard H. Arland)
To: [email-masked]
Cc: [email-masked]
Subject: Re: TUBE BANK(s) Idea!
Message-ID: <[email-masked]>

On Fri, 25 Oct 1996 07:37:36 -0500 (CDT) "Brian Carling" <[email-masked]>
writes:

>
>The idea is for a "tube bank."
>

GREAT IDEA!

I have a whole bunch of tubes that I would donate to the cause....been
collecting tubes for several years but don't have the time to go thru
them and test them all out. 

FB idea.

73 rich K7YHA

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

Date: Sat, 26 Oct 1996 02:20:19 MST
From: [email-masked]
To: [email-masked]
Subject: Re: Glowbugs admin ... please read.
Message-ID: <[email-masked]>

On Thu, 24 Oct 1996 14:37:03 -0500 (CDT) Conard Murray
<[email-masked]> writes:

> Hello to all 250 plus readers of the this list!

Hello Conrad, et. al.

> I am trying to do some work on the list and I would appreciate if you 
> would take time to send me a message telling me your e-mail address is 
> still valid and you are reading mail sent there. 

I subscribe through one E-mail address which is...

<[email-masked]>

> I also notice that most of you are just lurking out there. If you are 
> not too shy, drop the group a short note introducing yourself and what 
> you like to work on or what you have built or want to build. Remember, 
> you are the list and it becomes what you make it. 

I am one of the "lurkers" on this list, since I joined a few
weeks ago, and enjoy reading some of the posts on here.
I started using a Hallicrafters SR-400 as a Novice 3 years
ago, but I had some trouble with fuses for some unknown
reason, not because I had the wrong kind or size.  I picked
it up at a flea market before getting my initial Novice ticket,
and was able to use it right away when the ticket came in
the mail.  I didn't get a chance to try out the SSB or AM
portion of the radio, since I only had a 40 meter sloper up
at the time, and was limited in where I could operate.  Sure
was a nice radio when it worked, and had good sensitive
recieve and was a powerhouse on transmit, since I had
alot of 599 reports in the log.  :)

I hope to get back into the antique radio collecting again
soon.  By the way, my father is also a ham, and loves
those Collins and Drake lines.  He got a Drake "C-Line"
as a birthday gift from my Mother several years ago, and
it is his pride and joy.  For those interested, I am 26 years
old, live on a farm (hog and antenna farm), next door to
my folks.  I currently use a Kenwood 440S, and a 700 foot
longwire up 45 feet on a tower and REA poles.  I run
barefoot (actully my rig does), but I myself wouldn't dare
run barefoot in the cold basement. :)

That all from NE Montana, sure enjoy reading the posts
on the SIG... Keep 'em coming!

>Thanks for the help and best of 73,
>de Conard, ws4s
>listowner, glowbugs
> 
> Conard Murray  WS4S  NNN0UTN   [email-masked]
>217 Dyer Avenue                BA/GB net 1802.5/3579.5/7050 KHz        
>             Cookeville, Tn  38501
>615-526-4093
>          - LICENSED ONLY TO EXTENT INDICATED ON CARTON -
>

73 de Stacey, AA7YA
AA7YA @ AA7YA.#NEMT.MT.USA.NOAM
[email-masked]
Box 83  Whitetail, Montana  59276    (406) 779-3641
"The buck never gets here!"

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

Date: Sat, 26 Oct 1996 05:05:05 -0600 (MDT)
From: [email-masked]
To: [email-masked]
Subject: Hammarlund Coil Forms
Message-ID: <[email-masked]>

   I was viewing the text about the Doerle regen at:

   http://members.aol.com/caschwark/homebrew.htm  

   The parts list refers to Hammarlund XP-53 5-pin coil forms.  

   Does anyone know the diameter of this form?

   The other coil data seems complete.  I might build it, or at least use
   the coils in another regen project.

   Thanks for any assistance.  

   ****************************************** 
  ** Shane <[email-masked]> **              
   ******************************************               
        ** Edmonton, Alberta, Canada **                 
         *****************************       

             

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

Date: Sat, 26 Oct 1996 10:16:51 -0400 (EDT)
From: [email-masked] (John Levreault)
To: [email-masked]
Cc: [email-masked]
Subject: Re: TUBE BANK(s) Idea!
Message-ID: <[email-masked]>

>
>On Fri, 25 Oct 1996 07:37:36 -0500 (CDT) "Brian Carling" <[email-masked]>
>writes:
>
>>
>>The idea is for a "tube bank."
>>
>
>GREAT IDEA!
>
>I have a whole bunch of tubes that I would donate to the cause....been
>collecting tubes for several years but don't have the time to go thru
>them and test them all out. 
>
>FB idea.
>
>73 rich K7YHA
>
>

Indeed a great idea! I'd be happy to compile a list of the stuff I have.
Testing the whole batch would be quite time-consuming, but most of what I
have are NOS and I could test on an "as-needed" basis.

73 de NB1I
John Levreault

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

End of GLOWBUGS Digest 332
**************************