History
Riddingshill features on the 1959 Network Map with "existing or under construction" links to Carlisle and Cambret Hill (continuing towards Belfast) and a "programmed" route via Green Lowther to Kirk o'Shotts. The first traffic carried over the route to Belfast was the one-way network feed to Ulster Television. The route was intended to be shared with telephony which was added in the early 1960s. The route was progressively upgraded to carry BBC feeds and became the main telephony link between Northern Ireland and the UK mainland.
BT Archives features several photos from 1961 showing the installation of horn antennas on a square "pylon" style tower. These provided a new link via Green Lowther, with the original dishes retained for the Belfast route. Further photos from late 1967 and early 1968 show work associated with the installation of a new tower - of the "standard" type. At this stage links were being upgraded to carry 625-line colour television and the trunk telephone network was also expected to make greater use of SHF links.
The "new" tower survived the transition from horns back to dishes and the subsequent expansion and decline of the BT network, now serving as a mobile phone base station and a site for local radio station West Sound. The building is not of the standard pattern (the design was not finalised until slightly later) but is similar to those used at the other intermediate sites from Carlisle to Belfast. The original towers at all sites were also similar.
A 1966 OS plan at 1:2500 scale shows the L-shaped building with square tower "inside" - there is still some evidence of thus on aerial photos. The "new" tower was built on the southern side of the building, the orientation resulting in the dishes facing Cambret Hill being mounted slightly awkwardly on a corner. Pairs of "large" horns were used on the other routes.