There are many devices that can cause TVI (Television Interference) or RFI (radio Frequency Interference)
LED lights are noted
If your TV is running on batteries even standard lights (Lower the voltage) can do it.
Fans.. Some have burshless motors (no interference) others brushes (interference).
BOOK.. ARRL.ORG click on the store link look for Radio Frequency Interference.. I think they have a few books on the subject. I used to have one of them (ARRL's own) and it was very comnprehensive since it was written by people who actually know what they are dealing with.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times