History
Depden to Tacolneston was a short-lived spur route,with neither site being used in the main Post Office network. It is, however, of historical interest and can claim to be first in two categories.
- Use of 2 GHz
- Post Office installation at a BBC broadcast site
The single-hop link used 2 GHz equipment from GEC (type unknown) which was given the Post Office designation RS 9/2. The requirement was to provide a vision circuit for the new BBC transmitter at Tacolneston, covering East Anglia, which entered service in February 1955. It is unclear whether long term plans for BBC links were under consideration at this stage, but the initial service was provided by off-air reception of the London transmitter at Alexandra Palace - a regional studio would not open for many years.
The "Direct Pick Up" option was adopted: the London station was received at a suitable intermediate point with a one-way microwave link to the BBC site. Everything about this link was of a temporary nature: at Tacolneston the BBC initially used a Post Office mast while construction of the main structure continued. Equipment was in wooden huts and mobile trailers. The receive antenna at Depden was on a wooden pole with the microwave dish mounted on the roof of a water tower and a generator was required to power the equipment.
Full service from Tacolneston began in the autumn of 1956. The Post Office dish was (probably) transferred to the BBC mast at this stage. Earlier in 1956 the link had been modified due to the London transmitter transferring from Alexandra Palace to Crystal Palace, initially at low power. A new receive site was established at Thaxted (location not yet identified) with a 4 GHz link to Depden. The link via Thaxted was removed when transmissions from Crystal Palace were at full power.
By the late 1950s BBC network plans required a link from Birmingham rather than London. The Post Office built a new Radio Station at Wickhambrook, not far from Depden, and the vision circuit was re-routed. The Post Office Engineer in Chief's Annual Report confirms the link between Depden and Tacolneston was withdrawn during 1961-62.
Despite the temporary nature of Depden the Post Office had contracted with the BBC to provide the link on the basis that any "early" termination would result in a penalty. It seems a compromise was reached by redeploying the equipment to provide a new link for the BBC between Wickhambrook and Manningtree from 1962.