QCX CW single band transceiver
I found a very nice design / kit in QRP Labs eshop, so I decided to try it (40m version)...
The very detailed description and assembly instruction handbook is here. Easy to build (I did it over the weekend,
just few hours work).
I was especially interested how easy is to adjust phase shift network and how it performs. I must admit it is relatively easy -
adjustment can be done using built-in signal generator and signal strength indicator. Of course 100% rejection of unwanted signal
in whole audio band is impossible, adjustment is matter of compromise, but because we use relatively narrow band (limited by
audio CW filter), it is sufficient (for standart QRP operation) - supression better then 40dB.
So I can recommend it - performance to price ratio is great, so if you need a light weight radio for portable QRP CW operation it is a good choice.
I put it into a box made from cuprexkart (PCB material) with plexi cover - to be able to look inside :-)