History
This page documents the second route between Birmingham and Norwich which consolidated the 1960 Birmingham - Norwich TV link, "Backbone" and "Linesman" requirements and provided the potential for a telephony route from the Midlands to East Anglia.
The route started from the new Post Office Tower at Birmingham and ran via a new intermediate site at Twycross to Copt Oak, then along the 1960 route to Morborne Hill (Peterborough) where it followed a new path to the east via Wisbech and Swaffham to reach Stoke Holy Cross. The ultimate destination, Norwich Repeater Station was connected via cable. The section between Morborne Hill and Stoke Holy Cross carried Linesman radar traffic between Neatishead and other sites along the east coast and the route between Copt Oak and Morborne Hill was a spur to Backbone.
As a result of this history, some of the sites had been established earlier but the contracts to "join the dots" were awarded to GEC in 1964 for a L6 GHz system. Contract 23574 for the section Birmingham - Morborne Hill was originally valued at £89,498 with completion "1st Nov. 1965 or 4 months after access to buildings". The revised price at 31 August 1966 was £100,178. Contract 23575 for Morborne Hill - Stoke Holy Cross was priced at £68,078 with the same completion date and a revised value of  77,962. These were non-competitive contracts "authorised by HQ".
The equipment used is likely to have been the "first generation" GEC type 5555 which offered up to five working channels plus protection channel and suitable for 625-line television or 960 telephony circuits. Horn antennas were used at all sites - as this was not expected to be a major route only a single horn was used in each direction. The design of the tower at Oakham in particular would have prevented significant expansion. Backbone traffic between Copt Oak and Morborne Hill was carried over a GEC L6 GHz system covered by an earlier contract - this would have occupied one of the available traffic channels and may have included a dedicated "Protection Channel". The Linesman traffic east of Morborne Hill, however, was at 2 GHz so did not conflict.
We understand the route developed primarily for BBC television links. In 1966 a further contract 300511 was authorised in the sum of £59,498 for additional channels between Birmingham and Morborne Hill. "Equipment must be compatible and integrate with equipment already under provision by GEC. GEC are also required to shift equipment displaced from another link". [It is possible this relates to re-use of L6 GHz equipment initially used for the Backbone scheme around Manchester which was later changed to 2 GHz.]
Other archive material shows planned expenditure totalling £234,000 in 1966 to 1967 for "Birmingam - Peterborough - Tacolneston TV Radio Link (BBC1)" which was to be a two-way operational channel and protection channel. This is possibly a re-statement of the cost of the three contracts identified above. A further £433,00 was budgeted for the Birmingham - Norwich BBC2 link and another £65,000 for "Norwich - Birmingham Radio Link Conversion" which related to replacement to 625-line standard. The budget for the BBC2 link seems particularly high since it is described as a single one-way channel plus protection channel between Birmingham and Stoke Holy Cross. It may be this system operated on a different band and the cost included new antennas and waveguide.
By the 1980s the route had been further expanded to meet BBC and IBA requirements. The main feeds for BBC1 and BBC2 ran from Birmingham with a single "contribution" circuit in the reverse direction. An additional channel was provided from the BBC Peterborough site (adjacent to Morborne Hill) providing VHF stereo distribution to Tacolneston. IBA use of this route was limited: the main circuits for Anglia ran to and from London but a remote switch was installed at Morborne Hill to allow selection of local studios at Bedford, Northampton and Peterborough which shared a one-way link to Norwich. It seems two separate "radio systems" were in use, with two "protection circuits" available in each direction.
It is likely the BBC links remained on analogue systems until transfer to Energis in 1995. Migration of the BT network to digital links had started during the 1980s. It is unclear whether new links were installed between Birmingham and Norwich for telephony: the tower at Oakham would seem to have been a constraint.