For what its worth, the sidetone of my 20M QCX mini would be distorted/blanked by RF from my portable vertical. A choke on the antenna feedline solved the problem. So, yes, having the transceiver 10-20 ft from a compromise antenna can result in such problems. Others suggested ferrites on headphone or key wires or capacitors on their connectors would help. Or, ferrites on your power input
