Aerial monitoring and protection [TV transmitters]

The UK terrestrial UHF television services rely on a large number of transmitter stations to provide a comprehensive coverage for the UK service area. The majority of these transmitters are low power transposers, used to re-broadcast signals to a small local community. These transposers ultimately receive their signal from a high power main transmitter. The continuity of service is governed by the operational availability of these main transmitters. The high RF power transmitted from these main sites means that the aerial systems could be irreparably damaged if an aerial fault develops. As a consequence, Aerial Monitoring and Protection (AMP) equipment is installed at all these sites to turn off the transmitters in the event of an aerial fault. With the forthcoming UHF re-engineering programme, there is an opportunity to re-evaluate the whole philosophy of aerial monitoring and protection. The paper considers a range of methods for detecting faults to achieve this protection