I recently built my second
QCX-Mini, this one for 20 meters. It's such a fun a build and even more of a joy to operate. I took it out to my local park for a test run using my
homebrew, end-feed, half-wave, multi-band antenna. When the radio came on, the band filled with signals from a CW contest. I tried to respond to a few station, but apparently no one could hear me. I texted a friend who lives nearby and he was able flip on his HF radio and verify that I was indeed getting out.
Back at the house, I pulled up Hans' video on maximizing output power on the QCX and sat at my bench to work on mine. I hooked it up to an RF power meter and found my rig was putting out a whopping 1/2 watt. No wonder no one could hear me.
I adjusted the L3 inductor by spreading out the windings and managed to get right at 4 watts. But regardless of how much more I worked with it and the other two inductors, 4 watts was the most I could get. So, following Hans' advice, I desoldered the inductor and remove two windings. Once I soldered it back on the board I was able to get just over 6 watts. Perfect! I closed up the radio and packed it in the bag.
This weekend, I took it back out to the park. Again--being a Saturday--the band was jammed packed with contest signals. However, this time, after waiting for a pause in an exchange, I called a station sending CQ. Instantly he returned my call! I gave him the exchange and he sent, "TU." It worked! I had about an hour of daylight left, but I wound up with 14 QSOs, all of them solid exchanges.
