Here's the whole quote.

At that time, the Hannington UHF television transmitter was unusual in being one of the few transmitters which rebroadcast an off-air signal received from another transmitter (Southern Television's Rowridge transmitter on the Isle of Wight), rather than being fed directly by a landline. As a consequence it was open to this kind of signal intrusion, as even a relatively low-powered transmission very close to the receiver could overwhelm its reception of the intended signal, resulting in the unauthorized transmission being amplified and rebroadcast across a far wider area. The IBA stated that to carry out a hoax would take "a considerable amount of technical know-how"[4] and a spokesman for Southern Television confirmed that "A hoaxer jammed our transmitter in the wilds of North Hampshire by taking another transmitter very close to it."[2] However, like the Max Headroom broadcast signal intrusion a decade later, the identity of the intruder was never confirmed