Daily GLOWBUGS
Digest: V1 #122
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Purpose: building and operating vacuum tube-based QRP rigs
Subject: glowbugs V1 #122
glowbugs Sunday, September 28 1997 Volume 01 : Number 122
Date: Fri, 26 Sep 1997 17:14:59 -0700 (PDT)
From: "Tom R. Rice" <tomrice@netcom.com>
Subject: Re: 6N7 vs. 6SN7
>
> Another possible fly in the ointment is the fact that both triode sections
> share a common cathode. I have found this to be a big problem in some
> circuits.
In this regard, note the error in the Rockey Regen Book
where Rockey recommends a 6N7, but the circuit clearly
shows two separate cathodes. One section of the tube
serves as a grounded-grid amp, the other does the regenning.
A mere typo, I'm sure.
I'm building with 6SN7 substitutes, although I'm assured
by an "expert" I know locally that I'm gonna lose
substantial HF response, i.e., above 40 meters.
We'll see.......
73 de WB6BYH
- --
"Start off every day with a smile and get it over with." --W.C.Fields
Tom R. Rice
tomrice@netcom.com
Date: Fri, 26 Sep 1997 19:20:00 -0500
From: w5hvv@aeneas.net (Rod Fitz-Randolph)
Subject: Regens
As old an ol' fogey as I am, I haven't heard the term choke condenser
until recently and I have only the fogiest idea as to what it might be.
I've always used the potentiometer to vary the screen voltage (which I
now understand is secondary in preference to the choke condenser).
Could someone illuminate this Ol' Coot?
Thanks,
Rod, N5HV
w5hvv@aeneas.net
Date: Fri, 26 Sep 1997 20:33:40 -0400 (EDT)
From: JMarti1594@aol.com
Subject: Re: Regens
I love this group could someone send me a schematic for a regen so i can get
in the fun thanks scott kb9nyw
Date: Fri, 26 Sep 1997 20:49:36 -0500 (EST)
From: "Roberta J. Barmore" <rbarmore@indy.net>
Subject: Book reprint news
Hi!
Response has been overwhelming--20 so far! So I'll be getting an
estimate from Kinko's and probably start having 'em printed up if it's not
too unreasonable.
As soon as I find out what it'll cost, I'll post the price. Then
e-mail enquires will be responded to with my postal address. My usual
procedure is payment in advance; there's not a lot of capital to tie up,
so I have small runs (a dozen or so) done at a time. I can bankroll that
many, and then the first batch of checks roll over and bankroll the rest.
(Can you say "shoestring?" For sure....)
Thanks, guys! As I've already got the "master" in-hand, it won't take
too long to white-out the things I missed first go-round, and get the
printing process underway.
73,
--Bobbi
(At least one more book project is on the layout table, but it's still
a ways off. Details when it gets closer to completion. Another reprint,
this time a compilation of articles from QST of the '30s--anybody know
what the copyright status would be, or who to talk to at ARRL about it?)
Date: Sat, 27 Sep 1997 00:43:58 -0400 (EDT)
From: EricNess@aol.com
Subject: 1950 Ocean Hopper
W5HVV asked about the schematic and parts list for the Knight "Ocean Hopper".
Well, as it turns out I found an excellent write up on the Ocean Hopper in
an old magazine called the Radio Experimenter dated 1950.
I imagine the Ocean Hopper design changed a bit over the years but, the
1950 version was a two tuber, a 12J5 triode as the detector and a 117P7 as
the rectifier and audio amp. As one might guess whenever a 117 volt tube is
used, the original design is transformerless. An interesting twist is that
the heaters of both tubes are connected in series to "simplify the circuit
and five the tubes a longer life."
The regeneration in this design is controlled by a potentiometer which varies
the plate voltage to the detector (and thus the gain of the tube). In my
experience, this technique works well if you are listening to powerful
broadcast stations. However, a lower plate voltage will result in reduced
sensitivity .
For my October regen, I plan to build a version of the famous Ocean Hopper.
I will add an isolation transformer, filter choke to the B+ supply and
modify the detector to use a throttle condenser.
If anyone would like a copy of the Ocean Hopper magazine article which
includes a schematic and parts list, please drop me an email. Unfortunately,
there is no coil winding data but, we can trade notes as we cut and try coils
of our own design.
73, Eric WD6DGX
Date: Fri, 26 Sep 1997 23:23:05 -0600 (MDT)
From: Shane <toyboat@freenet.edmonton.ab.ca>
Subject: Hartleys, #45, 6SN7, 6L6
Hello,
Thought I would bounce this idea off the group.
R.D. Keys version of the George Grammer 1932 Hartley uses a 6SN7 to
replace the #45 power triode. The twin 6J5 (improved) sections are
paralleled to provide a smallish, but cost-effective and easily
available power triode.
It has been mentioned that the modernish and squat looks of this
war-child are esthetically annoying for a 1932 Hartley. Could not a
pear-shaped 6L6 glass unit be used with its screen tied to the plate?
In this triode connection it compares very favorably to the original
#45 as a low-mu power triode and looks good too. As with the 6SN7, the
bias resistor needs to be changed for the circuit, but the 6L6 as
triode seems a not-too-pricey and easily-available;;D*-!wt6
c7Y #45
substitute.
Then you just have to forget that it's really a beam power pentode
so you can dream audion dreams :-).
Regards,
Shane Wilcox
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Shane <toyboat@freenet.edmonton.ab.ca>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Date: Sat, 27 Sep 1997 10:49:24 +0000
From: janax@mail.li.icl.se
Subject: Tube for a regenny?
Hello.
Last night I dug really deep into my junkenboxen, all the way down to
the pile of really old tubes. I found a Philips A425 which is a
direct heated triode with a British B4 base. All I have on this is an
entry in the tube tester book. I tested it and it works!
Gm is just below 1 mA/V at 200V/4mA and -2.5V. Filament 4 volts.
Tube tester book said 200V/0.25mA at -2.5V so something is a bit off.
The tube is also marked 3.4-4V and 15-120V.
This tube would perhaps be a nice candidate for a detector in a
regenny. Before going to manufacture a holder for it... does anyone
have a British B4 or B5 tube holder for sale? I have one on the
tester but...
Finally, do anyone of you know anything about this tube?
Cheers,
Jan, SM5GNN
Date: Sat, 27 Sep 1997 10:13:56 -0700 (PDT)
From: Ken Gordon <keng@uidaho.edu>
Subject: Re: Hartleys, #45, 6SN7, 6L6
> war-child are esthetically annoying for a 1932 Hartley. Could not a
> pear-shaped 6L6 glass unit be used with its screen tied to the plate?
> In this triode connection it compares very favorably to the original
> #45 as a low-mu power triode and looks good too. As with the 6SN7, the
> bias resistor needs to be changed for the circuit, but the 6L6 as
> triode seems a not-too-pricey and easily-available;;D*-!wt6
Seems to me that the old 6F6 would make even a better version of this idea
since it was not a beam tube, and it is usually much cheaper than a 6L6. I
have not seen any in envelope types other than ST either.
Ken W7EKB
Date: Sat, 27 Sep 1997 17:51:57 -0500
From: w5hvv@aeneas.net (Rod Fitz-Randolph)
Subject: Re: Regens
Rod Fitz-Randolph, N5HV, wrote:
>> As old an ol' fogey as I am, I haven't heard the term choke condenser
>> until recently and I have only the fogiest idea as to what it might be.
>> I've always used the potentiometer to vary the screen voltage (which I
>> now understand is secondary in preference to the choke condenser).
>>
>> Could someone illuminate this Ol' Coot?
_________________________________________________________________________
Jim Glover, WB5UDE, responded:
>I believe you mean "throttle condensor".
>
>Sorry...no answers to your question here...
>
>--Jim WB5UDE
_________________________________________________________________________
Rod Fitz-Randolph counter-responded:
Hmmmmmm! Ur rite! Howsomever, when I throttle someone, I usually choke
'em.... same, same to us Ol' Coots!!! (I always did have trouble with
my words). My Ohio Valley Indian anscestor would say, "He fell and impaled
himself on his tongue".
Best Regards,
Rod, N5HV
w5hvv@aeneas.net
Date: Sun, 28 Sep 1997 04:30:29 +0000
From: Sandy W5TVW <ebjr@worldnet.att.net>
Subject: FS/FT: SBA-312 Marine SSB
Sideband Associates SBA-312 SSB transceiver, 12 channels, 2-16 mhz.
working, good finals, 100 watts out. Cosmetically about a 5-6. 115 vac model.
With photocopy of manual. $50 plus shipping/packing.
Trade for a good RAK receiver less power supply to someone within
driving
distance of New Orleans or someone going to Belton Hamfest.
73,
E. V. Sandy Blaize, W5TVW
"Boat Anchors collected, restored, repaired, traded and used!"
417 Ridgewood Drive
Metairie, LA., 70001
End of glowbugs V1 #122
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Created by Steve Modena, AB4EL
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