No Signal

I have an XM Sportcaster radio that only plays when the car is hot inside from sitting in the sun. It will play for about three songs and when the air conditioning reduces the temp in the car the radio quits and displays a message "No Signal". Anyone else have this problem?

You have a loose connection. Have you tried reseating the Sportster in the dock? Put a little pressure on it in different directions and see if it comes back on.