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Old March 14th 09, 03:51 AM posted to rec.radio.amateur.homebrew
Jim Jim is offline
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First recorded activity by RadioBanter: Nov 2006
Posts: 9
Default Homebrew Double conversion tube receiver Not HBR

I recently acquired a HOME BREW double conversion 23 channel CB
receiver, yes I now it's not a real boat anchor but given that it has
11 tubes plus several diodes , I thought I'd ask about it here. It
looks very well made. I was hoping that some one would recognize it
by tube line up. I have started drawing the schematic . It has the
following tubes, 6EH7 (the RF amp) , 12AT7, 12AU7, 6BN8, 6HR6, 6BA6,
6BE6, 6GX6, 12AX7, 6AQ5, and an OA2. It has 6 RF and IF
transformers.

The antenna is connected directly to an untuned transformer with the
RF amp feed by a cap off the secondary. The first oscillator uses a
29305 Kc crystal for the first oscillator stage. So a simple change of
crystal will put it on 10 meters AM. It has a “S meter” and what I
suspect is a meter adj. pot on the back. There is a octal socket on
the back labeled transmitter that has two lines jumped as well as a
voltage divider with a large electrolytic to ground in the middle of
the divider.

The tuning cap is three section with one section switched by a
control on the front panel. The tuning cap is driven by a very nicely
home made dial cord mechanism with a heavy flywheel. So far I have
figured out the RF and audio gain controls. The other two front
panels pots function are a question as well as the functions of four
multi section toggle switches. With the filter caps being bad. I have
not powered it up for more than two minutes.

Does anyone remember a home brew rig with these features HAM or CB? I
would like to find a schematic if possible. As I am only about half
way through drawing up one. I looked at the HBR site and it doesn't
seem to match anything there. But given the limited 23 channel
coverage (plus channels A-D) it looks like it's from the late 1960's
or real early 1970's .

Thanks For any Info.

Jim