Sirius, T-Mobile Spat Over Airwave Interference

Sirius XM customers in a few big cities have been complaining about losing their satellite radio signal and the company says it has found the culprit: interfering T-Mobile cellphone towers. T-Mobile US says it isn’t doing anything wrong. Instead, it blames Sirius XM’s radios for the problem. Now Sirius XM has escalated the dispute to the Federal Communications Commission, asking the agency to intervene.

A senior FCC official said the agency is trying to understand the cause of the problem because all of the involved airwaves have been in use for years. The official said it still too early in the process to assign blame or responsibility. The conflict between Sirius and T-Mobile derives from a quirk of physics, caused by something known by radio engineers as intermodulation. This happens when two airwave frequencies combine to create a third, similar to ocean waves coming together and making a new distinct wave. In this case, two airwave frequencies used by T-Mobile have produced a new frequency inside Sirius radios that is disrupting service. Both parties agree on the physics but they disagree on the fix.