[GreenKeys] Length of tape

Fri, 15 Feb 2002 01:30:48 -0500

Hi Jack!
   The original article on the W2BFD oscillator and converter was published
on page 18 of the November 1946 CQ Magazine. That was when I first got
interested in RTTY! My original subscription to CQ began in 1947 so I don't
have the Nov 46 issue. Sorry about that. The essence of the article was
apparently published in the First Edition of the Radio Amateur's RTTY
Handbook by Wayne Greene, W2NSD and Byron Kretzman, W2JTP.
It is on pages 36 thru 39. Basically it used two stages of 6J5's in tandem
driving a 6V6 power output tube for each of the mark and space channels.
The 6V6's then drove a conventional polar relay which in Kretzman's case
he hand manufactured out of a telephone ringer and another one out of a
balanced armature magnetic speaker!! Byron also made his own inductors
for the tuned circuits out of miniature transformers by removing the "I"
laminations and spacing the "E" laminations from each other by a 1/4" thick
"slab of insulating material." His two-tone AFSK oscillator was made
with a 6SN7 oscillator driving a 6J5 output stage. If you are really that
interested I might be able to reproduce the pages from the book but they
are already very small, apparently having been photo reduced from the
original. If you are really interested in vacuum tube technology I also
built a very complete version of the TTL-2 which was about the final
ultra-ultra design before the ST-5 and ST-6 units came out by Irv Hoff.
My TTL unit is in a 19 inch rack cabinet so you can get an idea of the
size. That's enough for now. Get in touch with me if you are really
interested any further.
    John, K2AGI

----- Original Message -----
From: "Jack" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 14, 2002 21:51
Subject: Re: [GreenKeys] Length of tape


> Does anyone out there have a schematic for the W2BFD converter(s)? I
believe
> they were built for 2 Meter autostart operation. Lots of tubes, relays and
> inductors. I've seen pictures of his handywork, but never a schematic.
>
> Jack WA2HWJ
>
>
>
>
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