[Elecraft] K3/KPA500/KAT500 SWR problem

[Phil & Debbie Salas]

I haven’t had this problem.  However, in addition to Igor’s thoughts on a high reflected signal, here is another thought.  A strong signal (like you can have in contest environment and/or multi-transmitter/multi-antenna set-up) could be counted by the KAT500 frequency counter resulting in the KAT500 jumping to a different memorized frequency setting.  I don’t know what the threshold sensitivity of the KAT500 counter is, but incoming signals can be very high under some conditions.  I wonder if disabling the internal KAT500 frequency counter might be something to try – especially when band data is provided by the auxbus cable.

Phil – AD5X

“It may be not relevant to this particular case but another reason for weird KAT500 behavior can be strong interfering signal of a neighbor or nearby broadcasting station. I did run into situations where such signals induced up to 5 volts into low band antenna. Then KAT500 counts that signal as reflected and thinks that SWR is very high. One may try to connect broadband spectrum analyzer to the antenna and see what is going on. If it is broadcasting signal well below ham bands then high pass filter between the tuner and antenna can help.73, Igor UA9CDC”