Thanks guys. I probably didn't make it clear - the transponder antenna is a factory install and not accessible. All I have to work with is the bitter end at the panel. So, the Aircell 7 cable is a done-deal. Google turns up the part number I need. Only problem is that there doesn't (currently) seem to be a US distributor. Working my UK network now. And Jim, I will look into the alternative of using the RG6U, but I'm not sure the core diameters are right.