Do you only have the problem when the radio is hot? ?My oldest 7K is only used mobile now and it exceeds 40 C here often in the summer and I have no problems. ?My SUV isn't garaged, so it gets HOT inside, but I haven't measured it. ?I usually don't turn on my 7K until the car has had a few minutes to cool down.
I did some thermal analysis in 2011, although below 40 C. ?During TX when the internal fan turns on, there should not be a problem even with CW key down for 10 minutes continuous at 100 watt output. ?I can send you the info if you wish, if you really feel you have a thermal problem.
The radio is only specified to operate at a maximum of 60 C., which true even of expensive Motorola commercial radios. ?I suspect that the 7K might have to be operated at reduced duty cycles at 60 C, however....
Steve, W3AHL
Steve W3AHL