From my research, this heat issue appears to be related to the radio... I have posted data that shows when the radios are on they are drawing 2-3 watts from the battery to put out what the FCC says is 0.25W of power. I'd be willing to bet it is the same with the Diamond. If your interested, here is the post:
http://forum.ppcgeeks.com/showpost.p...7&postcount=35