I've got a 7180 in my truck and today I noticed that (on some channels) that when I hit the PTT the radio turns off. It immediately comes back on when the PTT is released. It doesnt do it on every channel which is why i haven't noticed it before. Any thoughts on the culprit? It does not matter whether the truck is on or off. It does have the ignition sense cable tied to turn the radio on with the truck power.