Like many people I was very excited by QRP-Labs work to bring sideband to the excellent, compact, high performance, digital rig, the QMX. I ordered a built version and have been using it in the field.
My setup, in a small waterproof box is quite compact but I plan to put together a portable radio with a QMX, rechargeable battery and some sort of antenna tuner. For this project I ordered the kit version and have now completed construction. It's a dense six layer board. The surface mount components are all pre-soldered so most of the work is toroids and connectors.
The QMX has built-in diagnostics, including RF bandpass and low pass filters. After my build I could see some problems all of which were due to me not managing to solder to enamelled wire. At times, inspection under high magnification revealed a solder joint where the solder seems strongly repelled by the wire. After a bit of debugging the radio is working well.
On the bench I run it from 12.0V via a linear regulator (I built the 12 not 9V version). (My bench supply of 13.8V is too high. I get 5W out on 80m and about 4W on 40 and 20m. Performance as a WSPR transceiver is really excellent.
If you run in to trouble there's some great resources including Hans' troubleshooting guide which includes a faultfinding log of fixes he's needed.
Also there is an active QRPlabs discussion group where people help each other. I've enjoyed this kit very much and it's a really wonderful radio.
I've been running it receiving and transmitting WSPR almost continuously for about a week. Rock solid. Sometimes reception of my signal is amazing (when there aren't solar flares that kill the bands). Here's a single transmission on 40m reported by 94 stations:
It also receives exceptionally well.
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