Good night, Since 2014 when I bought my car I use a FM transmitter inside it to play my bluetooth musics, to escape for every radio in city I put the radio to work in the highest frequency it works that is FM 107.90Mhz. A couple of years now I started to notice a very strong and loud interference and a white noise overlapping my music everytime I passed near every Gas Station. So Today I drove with 3 different radios in the same frequency 107.90FM and it happened in all my radios, those strong interference, only when I passed near the gas stations... So I googled it and find nothing about. What can be this strong interference on my radios in this frequency? I don't know where I could ask it, but I pretty sure it's physics area. The Gas stations doesn't have radio transmitters or antennas. Nothing near that could interfere with that weird loud white noise
Possible sources of noise:
- switching power supplies; modern switching transformers interrupt current with high frequency (kHz) to transform between high-low voltages; the rectangle-wave current makes the transformer radiate;
- digital electronics and its wiring: computers, computer network wiring work close to MHz frequencies;
- electric motors with brushes where sparks occur; arcs and sparks produce broad-spectrum radiation;
- faulty isolation or otherwise faulty electrical equipment which makes electric arcs occur.
All these are likely to be present in a modern business building, including gas stations (pumps, computers, air conditioning system).
For more on the sources of EM noise, see for example