Been looking at this one on and off for years. The official line - that it was a pirate broadcaster somewhere in the south of England using a relatively straightforward FM override technique - has always felt a bit too tidy to me.
The signal interruption itself is technically interesting. Overriding a broadcast transmission in 1977 required either significant equipment or inside access. The voice modulation, the specific phrasing, the timing - none of it screams ". Bored student with a transmitter." Southern Television's own engineers apparently couldn't fully account for the override mechanism at the time, which doesn't get mentioned nearly enough in the ". Debunked". Write-ups you see floating around.
What I find odd is how calm the whole thing was handled institutionally. No serious investigation that we know of, no prosecutorial effort, nothing. You'd expect at least some noise from the IBA given the regulatory implications.
The voice itself has been analysed a fair bit
Has it though? Properly? I've seen amateur spectral comparisons but nothing rigorous using modern audio forensics. If anyone's done actual formant analysis on the original recording I'd genuinely like to see the methodology.
My own read - and I'll acknowledge this is speculation - is that the ". Pirate broadcaster". Explanation was adopted because it was convenient, not because it was proven.
Still very much an open file as far as I'm concerned. Anyone here actually dug into the transmitter infrastructure of that period? The specifics of how Southern Television's signal was distributed in '77 would tell us a lot about what would've actually been required.