have a GME 3200
UHF radio mounted in the centre between the seats.
Noticed on the last trip that sometimes we had transmission problems.
On TX, the display would flash or blink quickly, say a few times a second and our friends reported that they heard a high pitch sound but no voice.
Got it working in the end.
1st problem was that we had a large metal object, in fact a 12v charger for the computer, next to it. Made sure no large metal objects were with 50cm of it and it transmitted fine.
2nd problem. Later into the trip, first thing in the morning, same problem. Nothing large near it. Once the engine was started and we got going all was OK. Worked out that the radio was hooked up to the 2nd battery, and the battery was down to about 12.2V. Fridge had run it down and the low voltage cut out on the fridge had come in.
Swapped the radio to the main battery and all OK.
Doh, of course they don't work when they don't get enough juice. :o)
So a couple of things to look out for when travelling.
Live and learn.