"You should have connecred Rx from radio to Tx on EB and vice versa.
If you're upgrading ground module's firmware - you have also to connect air module to PC and upgrade it's firmware to the same version. And also check if both modules have the same…"
"I've tested it before, both with NMEA and proprietary uBlox binary protocol - all works fine if you'll set correct baud for radio link.
But the question was asked over a half year ago and I'm not sure if is still valid..."
"NET ID has default value and you're using to much channels (max is 20-30 for stable work).
But IMHO this is not the root for your problem. If you're able - check your pair with different modem to find defective."