I'm a newbie to amateur radio and recently purchased the FTM-400XDR. I am having the exact same issue in my vehicle as mrweather commented on his his previous post. I get white noise across the active band I am on (top or bottom) as well as any station I switch to and it lasts for anywhere from one to five minutes. it doesn't do it every time I'm in my vehicle and, like mrweather, it seems to be affected by the temperature and does it more when its cold and damp. I can make the white noise come and go by wiggling either the microphone cable or the separation cable where they plug into the main radio body, but once the noise has stopped I cant do anything to make it come back. I've moved the radio around to several different locations in the vehicle and it doesn't seem to affect the problem. I can take the radio inside the shack and it never gives any problem. I'm new to this site as well, so I'm not sure how all this works, but if mrweather or anyone else has found a solution to this I'd be grateful for some input. Btw I love the radio as well. The white noise is annoying though to say the least. My 3200 and FT-90r don't give any problems in the vehicle.