I remember the TV reports from the TF having rhythmical interference, every 5-10 seconds, which I always assumed was from a rotating antenna.
Quite probably. In the mid 1980s I had a video camera that videoed to VHS tape on a battery-driven VHS tape recorder.
I videoed at the Farnborough Air Show and was bothered by interference of a persistent beep-beep on the sound track. Examining the footage when aircraft were taking-off for example, it was quite clear that the rotating (Decca?) radar antenna seen in the background was the source of the interference, each beep coincided with the sweep of the antenna as it rotated and beamed in my direction.
A right pain which spoilt an otherwise good video.