Which implies the problem with the GPS sensor is killing the network communication signals.
General way this thing works is that you've got 2 wires for intercommunication. Each device listens for an opening on the bus, then puts out a header saying what data it is sending, then transmits its data followed by a stop signal to say it's done. At that time, the next device will see the bus is clear and send its data, followed by a stop signal, and so on and so forth.
So, most likely, either your antenna is pulling the entire bus down so nothing can talk or it's not sending a stop signal to say the bus is clear. This has nothing to do with whether the antenna is receiving a satellite signal or not; just its effect on the network.
If someone nearby has a the same antenna, see if you can swap it in to yours to verify it's your antenna. Odds are pretty good it is causing the problem.