Nothing in the system using power other than the rig itself. I've taken out the
swr meters etc. that were using their own power supplies.
Hum isn't constant in the system. Recordings that I've heard distort more at
voice peaks.
When I've used the hand mic in the past the underlying hum seemed to pretty much
go away but peaks were still distorted.
Tom
Tom Brennan KD5VIJ, CCC-A/SLP
web page http://titan.sfasu.edu/~g_brennantg/sonicpage.html