Have a 50x1 and it acts like it overheats when transmitting longer than a minute on repeater channels. Fan comes on a few seconds before it reboots. Don't use it on simplex very much, and it is direct powered to the battery, and has a no-frills magnetic mounted 1/4 wave antenna, with a swr of 1.2, pickup truck roof center mounted. Really hope that it isn't defective, but its supposed to be repeater capable, so I'm pretty sure it isn't exceeding the duty cycle. Any insights?