Okay, I'm convinced this overheating is not the GPS Puck, but the SkyRadar-D unit. Even though it is silver, it gets extremely hot in the sun. The unit also generates quite a bit of internal heat. I have had some success with covering the window over the SkyRadar with a white piece of paper, but even this isn't always sufficient, and I have to shutdown the SkyRadar unit for 10minutes or so for it to cool down.
I'll purchase the remote antennas and get the unit out of the sun to see if it works better.
--Bob