So got my radio and all accessories all installed and thought all was good to go... until the first time I pushed the Push To Talk button with the engine running. As soon as I pressed the button the engine died. Long story short, I think it’s a Radio Frequency issue. I mounted my antenna on the roll bar via Rugged Radio’s roll bar antenna mount, just behind the passenger seat, which isn’t far from the flag mount you used. When I press the Push To Talk button with the engine off but the ignition on, I get a bunch of relay cycling from the area behind the passenger seat which I assume is where the ECM must be located. Two questions for you... do you know if your installer used any RF shielding material to shield the ECM from the antenna? And, do you know if your antenna is a 1/4 Wave or 1/2 Wave antenna? It should be identified on the antenna label. Thanks for your help!