Hard to get all parts in minima to working together.
I have used
the receiver in the summer to listen on 80m band, when I was in the shack. Now
when all puts together it starts sound very strange, I found out that the capacitor
330uF clos to LM386 Vcc was not connected! It solves this problem.
Strange behavior
when modulation, needs more decoupling at mic amplifier T13 R34 10 ohm changed
to 47 ohm, C43 50uF changed to 470 uF.
To get little
more drive I change PA-Drive 2N3904 emitter resistor from 22 to 10 ohm, see Pa driver.
In transmit
the modulation passes to LF amplifier, a FET 2N7000 shorts T15:B to ground,
gate to 47kohm to +T.
Found that output
is rather high even if no modulation. Put in a classic 10 turns trim pot 100
ohm to D3,D4 give around -40 dBc with no modulation.
Last
problem on 21, 24 and 28 MHz is lot power when touch ptt., found out that shielding
was needed between LP-Filter after PA and LP filter on main board(60 dB gain).
I will try
to put up a vide as proof of working transceiver, its not a hi-tec. TRX but its
working and I have learn a lot. Have made around 10 QSO, One Sweden to Netherland
59 report on 40m.
Stay tuned one last nots from this project.
Nice job Leif. I just have started to assemble mine!
SvaraRadera