I've followed the instructions to the T and can't seem to get my DX7 to bind to my brand new airtronics rx500. Anyone heard of this issue before? any tips?

Airtronics receivers won't bind to a Spektrum radio. You'll need a Spektrum receiver or a compatible clone.

2.4 systems (with the exceptions of a few clones) arent cross compatable.

You need a DSM2 or DSMx reciever.

Sorry to say that the answers you've been given are correct...at this time, with 2.4, binding is brand compatable except as mentioned