TV DETECTION

On 1st February, 1952, a newly developed technique for the detection of television receivers was demonstrated to the Press in the courtyard of King Edward Building, near St. Paul's, London, in the presence of Earl De La Warr, the Postmaster General, and Mr. David Gammans, the Assistant Postmaster General. The Postmaster General said, in a speech to the Press, that it was estimated that between 100,000 and 150,000 unlicensed television receivers were in use and that the users of such receivers were receiving free entertainment subsidised by those who had paid. He went on to outline the steps that were being taken by the Post Office to track down users of unlicensed receivers, not only in London but also in the Provinces. A film, showing the first detector van in operation was shown in Television Newsreel on 1st and 2nd February, 1952, and the principles of the detection technique employed were given by Mr. Gammans in a Written Answer to a Parliamentary Question in the House of Commons on 30th January, 1952.

The equipment, which is suitable for fitting in a standard Post Office Radio Interference van, enables the majority of working television receivers on both sides of a road to be detected, and the houses containing the receivers to be located, as the van moves along the road. The television receivers are detected by means of the induction magnetic field emanating from the line-scanning coils of the receiver; it is important to note that almost all working television receivers produce this field, that it is independent of whether an outdoor or an indoor aerial is used and that it is not readily possible to screen receivers to reduce the strength of the field to a degree such as to make detection impossible.

The first TV Deteector vehicle was a Morris Y Type.

This vehicle and it's equipment is documented in Radio Report No. 2260.

POEEJ article on Radio and TV detection - 1963

Last revised: February 04, 2025