Lots of articles on cosine interference at Field Day. Generally, * separate antennas * k3s, Yaesu, kenwood NO, NADA ICOMS, big Elecraft pitch * widely spaced antennas, in our case around the yard perimeter not crossed etc, longer runs of coax * band pass filters * tuning stubs on the antennas * duplexers. Sent from my iPad KC1BOO, Aka Crash