If there is a local VHF FM station on 97.3MHz this could cause problems to some radios having a Local Oscillator Frequency 0f 10.7MHz. If memory serves its called Second Channel interference...97.3Mhz might just be a local commercial station...
It is indeed - into LHR you have LBC's FM service radiating a few KW on 97.3 from the Croydon mast. Although, knowing that paticular transmission chain very well indeed, I have to say that any breakthrough would have been due to tropo & not harmonics from 97.3 off of Croydon
