History

Calisle - Kirk o'Shotts formed part of the "programmed" work as of 1959 and was part of an overall plan to consolidate the main television links onto a microwave system running from Manchester via Carlisle, replacing the 1952 east coast link and use of coaxial cables. Contract 21882 was awarded to GEC in May 1960 at a cost of £90,201 for a L6 GHz system. STC did not bid and a slightly higher offer from Marconi was rejected. The agreed "Ready for Service" date was May 1961. The contract was amended in August 1966, with an additional channel between Carlisle and Kirk o'Shotts and two in the reverse direction.

The original scope was defined "This specification relates to the general supervisory requirements of a radio-relay system comprising up to six RF channels and forming part of a main trunk network within the U.K., and covers the control, testing, monitoring, interconnection and switching facilities".

The link would run from Carlisle, via Riddings Hill and a new site at Green Lowther, to the existing terminal at Kirk o'Shotts. Major work would be required at all sites, however, partly due to the intended use of horn antennas. At Carlisle a larger tower was built over the existing structure, Riddings Hill received a replacement "Standard Tower" and at Kirk o'Shotts a much larger building was provided, together with a replacement structure.

Further channels were added via Contract 23556 in December 1963 and 300512 in 1966, with RFS dates 19?? and 1969 respectively.

A 1984 network diagram for the Carlisle Television Network Switching Centre suggests three bands were in use with six vision circuits running north. This included two circuits for ITV, allowing STV and Grampian to receive different contributions from "network" when required, together with BBC1, BBC2 and Channel 4. The sixth circuit was used for BBC FM Stereo transmitter feeds. In the southbound direction ITV and BBC had one vision circuit each - this would have prevented Grampian and STV from feeding programmes to other regions at the same time. [Think another circuit was added later?]

In the 1980s digital telephony links were introduced for System-X.