Hi All,
I mounted the board in a case I picked up at a fleamarket and have been enjoying listening to the QCX this weekend.? (some kind of Italian CW contest this weekend...)? I am really impressed with the receiver performance.? One issue I have noticed is that when a very strong station (i.e. S9+++) comes on frequency I have to tear the earphones off.?
I found the "AGC" for Bitx circuit but was wondering if some kind of clamping of very strong signals could be achieved with a zener diode between pins 6 and 7 of IC10B.? Ideas / comments would be welcome.?
As may be seen from the output waveform (0.5V/div and X10 probe into a 50 ohm dummy load) photo I still need to do some work on the LPF toroids.? My initial probing around showed almost 3 dB drop across the LPF - in spite of great care taken to wind the toroids to design value (AADE L/C meter).? ?Moving the windings around with a plastic alignment tool does not change power output noticeably.? Next time I take the box apart I will see if I can find one toroid that is attenuating more that the others and adjust the windings on that.? ?Meanwhile I logged good reports from UA4 and 9A5 so 2.25 W is workable.? My CW skills were much better 40 years ago? :)
Great kit - very enjoyable build.
73
Earl, 4Z4TJ
Earl