Hi, K2XI here. I am having problems with RF feed back, mainly between V H F and 6 to 15 meters I have good grounds. I am using LMR 600 on V H F , Double shield RG 8 on HF. The RF affects both radios regardless witch one is transmitting. The RF problem goes away after 15 meters 20 meters down it is OK, no problem at all ! Thanks K2XI, David Stambuck, Jr.