[AMRadio] FW: Homebrew receiver

[Brett Gazdzinski]

I finished the power supplies, and tried all the mixer designs
in the 1967 handbook, (page 99), circuit b was first, the load on the
LO stage was too low and stopped oscillation.
Circuit a, injecting he LO into the grid worked well, but tuning the
antenna input circuit changed the frequency a lot!
Both these designs need a buffer amp between the LO and the mixer to work.
I built design c, like in the first homebrew, and it worked fine.

I then hooked up the Kiwa filter board, and into the 1st IF amp, that
went well, built the 2nd IF amp, and it works but has a nice oscillation,
really strong!

The antenna tuning circuit was built, and needed some fine tuning,
and still needs more fine tuning, and the LO needs some adjustment, the
frequency
changed quite a bit after it was hooked up to the mixer. its a bit on
the low side, and only tunes up to 3900 or there abouts.

I tried some things with the IF oscillation, but got no place,
the gain may have to be reduced, and things rewired a little,
it looks ok, with very short leads between all the components, correct
bypass caps, thick ground wires running to the center of the tube socket
(metal post), so I don't know why it makes such a GOOD oscillator.
I should look at the Gonset G76 I have, it uses two IF amps, but
uses 12BA6 (6BA6) tubes, maybe I could duplicate its design and
construction.

I had problems with the 1st homebrew if amp oscillating, but forget
how I corrected it...

I still have the detector, S meter, muting, agc, and manual gain circuits to
build.

So far, it LOOKS very good, the chassis paint came out very nice, no
extra holes, parts laid out straight and so on.

Brett
N2DTS