I mean, magnetic ballast is working at 50 or 60 HZ. I dont see how it would interfer with any radio communication at many KHz's. I'd expect trouble like that only with HF ballasts

@Powel:
HF ballast should be mounted as close as possible to the lamp with as short HF wires as possible and run all that wiring parallel and as closest to the lamp.
Good quality ballasts have marked the "hot side" output terminals, what should be really made short - the ballast should be placed closer to that end of the tube.
So always cut the wires to just fit (with the required manipulation margin, but leave nothing more).
Very frequent mistakes are jamming the excess wires into chunks and keep that in the fixture. Such chunk then act as "excellent" disturbance coupler to the external world, same as ballast placed to the ceiling and lamp hanged few feets below - this create "nice" loop antenna to radiate all the lamp current...

What I see, very huge amount of electricians ignore the fact, then HF ballast is a high frequency device and ignore all rules in routing high frequency circuits (the related ones usually printed in the ballast installation manuals/documentation). I think here is very large gap in their training, causing severe interference problems with incorrectly made installations.

In some fixtures there is such distance between the lamps that wiring from the ballast to at least some of the lamps is a problem. In others the lamps are basically in series, so the 2 parallel lamps alone (with the distance between them) form the antenna

I have seen a manual that came with emergency module (low power instant start), that contains a scheme on how to connect it with a HF ballast to the lamp. Both L wires from the ballast are going through the module (to be disconnected by relay when in emergency mode, and disconnected from the emergency module when normally working). There is 1 wire from the emergency module that is permanently attached to 1 of the H wires of the lamp. So i assume that during normal work, 1 end of the winding of the output transformer of the emergency module is connected all the time to the HF ballast output H side. Then this would be coupled all the way through the emergency module as well (capacitance between coils in the output transformer, and since then there allready is current then inductance as well), possibly into the electric grid too