247 Metres Radio 1, 259 Metres (except it wasnt) Radio Caroline, 257 Metres Radio Orwell. The splat from Radio Caroline at 50kW did overwhelm the poultry 280W from Orwell making it unlistenable towards the coast and yes I do remember there was another Tx installed at Foxhall on 212 Metres for a while until Caroline went to 963 (319M) I think.
Soon to be even more clear spectrum , in the daytime anyway.
I seem to remember that Radio Orwell advertised as 257metres. Caroline on 259 was actually around 254metres, so there was a problem. I have a vague recollection of Radio Orwell simulcasting on another wavelength (around 212m) for a short while, until Caroline tweaked their frequency.
I live in North East Essex and also remember very well hearing the early years of Radio Orwell on 257 (1170). It was never quite as enjoyable for me as the likes of Radio Mi Amigo but had a fascination as it talked about places I had heard of locally and businesses.
In fact, I seem to remember that radio Mi Amigo had to change frequency when Radio Orwell started as it was on the next channel (up one?) to it and splashed all over Radio Orwell near the edges of it's coverage area.