I had a good day yesterday. After I finished the grocery shopping and yardwork, I was able to grab a short catnap before my weekly Skype session with Bob W3BBO.
Afterward, I went down into the shack and installed one of those new S40A1 diodes that I had ordered for my Astron RS-35A. After soldering the wire back on and installing a new fuse, I crossed my fingers and hit the switch. The fuse didn't blow, I heard that satisfying hysteresis hum and measured 13.65 Volts at the output terminals. Huzzah!
That inspired me to put the KXPA100 back in line. Surprisingly, I remembered how all the cable connections went and everything seemed to work fine - for a few moments. And then came some agita.
When I would try and tune up on 20 Meters, I would get an "ANT FLT" - antenna fault error on the KX3 display. The receive went dead - everything remained on, but I couldn't hear anything on 20 Meters. I checked the other bands and they were fine. I went back to 20 Meters, took the PA offline and everything was perfect!
What the heck?
It turned out that when I would switch the KX3 over to 20 Meters, for some reason unbeknownst to me, and perhaps only to God, the KXPA100 would switch from ANT1 to ANT2. I only use the ANT 1 input and I switch between the Butternut HF9V and my W3EDP using an antenna switch. This makes it easier to disconnect antennas before a thunderstorm. I only have to disconnect the coax going from the antenna switch to the back of the KXPA100 instead of disconnecting two antennas from the back of the amp. It was a simple matter of hitting a button on the front of the KXPA100 to make sure I was on the ANT1 input. From there, I switched to the other bands, and then back to 20 Meters to make sure the amp stayed on ANT1 and did not change over to ANT2. Success and a sigh of relief!
The beauty of the KXPA100 is that it allows me to stay at 5 Watts all the time. ONLY when I increase power output above 10 Watts does it kick in and go to work. However, it has the same internal ATU as the KX3 and as long as it is powered on, the KX3 will use the KXPA100 ATU no matter what the power.
That done, I worked four POTA stations, including EC1R in Spain on 20 Meters. I tried calling him with 5 Watts several times with no answer. I then dialed the output up to 50 Watts and was answered, first call. I got a 559 report and I gave him a 579 report.
It's comforting to know everything works.
72 de Larry W2LJ
QRP - When you care to send the very least!
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