Hi Hans, The first thing to check for is insufficient power-supply voltage as measured by KXPA Utility on key-down at full power. This is the usual reason for lower power output. If it's too low, you might try any of the following: shorten the supply cable, double up the cable (there are two APP jacks), adjust the supply voltage slightly higher (it's rated at up to 15 V), or make sure you don't have high-drop fuses or other devices in-line with the cable.
Power output of the KXPA100 is specified as: Max. 100 W @ 13.8 V, 1.8 to 29.7 MHz (80 watts 50-54 MHz) PEP, CW/SSB/DATA, +/- 1 dB And as noted in the specs, maximum power output, as well as the drive power to reach a given power output, both vary per-band. Your results do fall into that +/- 1 dB spec range. However, we actually test the amps at 100 W in the factory and it is very rare that they don't make 100+ W on all HF bands. (We could have specified it as -0.5/+1.0 dB based on our cumulative test results.) We tested competing amplifiers that use the same PA devices, and they too have a wide range of drive required and max output, varying per-band, and sometimes a dB below 100 W. This is typical of available 12-V-class MOSFETs. I do have a task on my list to increase the maximum allowed drive from the KX3 when higher power levels are used. We've been very conservative in this regard, so far, since KXPA100s are often used with marginal power sources and antennas in the field, or mobile. We don't want to over-drive, which could result in splatter or distortion of the KX3's virtually click-free CW key shaping. If you need further assistance with this, please contact customer support. 73, Wayne N6KR On Jun 24, 2014, at 12:11 PM, Hans J Rasmusen OZ7BQ <oz...@yahoo.dk> wrote: > Hello, > > My KXPA100 ser.nr. 00822 has now been on the air for several months ….power > varies from one band to another…. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
