SHF Radio Terminal Type MH140
SHF Radio Terminal Type MH140B, Drg 1735, Serial 009. (19 inch rack containing 14 modules and klystron unit)
- Object Number:
- 1991-397 Pt1
- type:
- radio terminal
British Rail York-Newcastle Microwave Communication Link in use from 1964 to 1989. Part of the intermediate installation at Darlington Station.
Marconi Italiana MH140B SHF radio communication used between 1964 and 1989 at Darlington Station as intermediate station on British Rail York-Newcastle Microwave Communication Link. The equipment was installed in the early 1960s and provided the bearer for the main trunk telephone network of British Railways routed on the east coast. The network was as follows:
York Telephone Exchange (46-foot tower on a 102-foot building) to Woolmoor Repeater (108-foot ground-based tower): 24 miles
Woolmoor Repeater to Darlington Telephone Exchange (92-foot tower on a 28-foot building): 18 miles
Darlington Telephone Exchange to Ferryhill repeater (150-foot ground-based tower): 11 miles
Ferryhill repeater to Tyne Marshalling Yard, SHF Terminal (376-foot ground-based tower): 14.5 miles
Tyne Marshalling Yard, SHF Terminal to Newcastle Telephone exchange: 4.75 miles via coaxial cable
The concept of using such a microwave radio link network for the British Railways trunk telephone network came about in the early 1950s when the network was rather more basic. The main connections were overhead line wires and there were generally only one or two circuits available between centres. Additionally, most telephone exchanges were magneto, if any existed, and telegraphic communication was largely through single-need telegraph instruments.
Around mid-1955, then Telecom Engineer (NE Region) P.W. Hanstock and his Chief Signal and Telecom Engineer A.F. Wigram became involved in finding the solution to severe congestion on the existing telephone line between York, Darlington and Newcastle. Some subscribers might have to wait up to six hours to make a call and so many subscribers reduced the number of calls they might otherwise have done.
Research into modernisation and increasing the number of available circuits suggested the best solution was a SHF microwave network which would be 1/2 the cost of a conventional cable system and 1/15 the cost of renting the circuits from the then GPO telephone system. Additionally, excepting rare period of deep fading during exceptional atmospheric conditions which may give rise to a slight increase in the noise level of circuits, the performance of a microwave system was comparable to that of a contemporary first-grade carrier cable trunk system.
There were numerous challenges: the GPO was strongly resistant to opposition to their telecommunications network. The British Rail SHF microwave network was believed to be the first private microwave network in Europe. The network was mostly achieved through the persistence of then Telecom Engineer (NE Region) P.W. Hanstock and his Chief Signal and Telecom Engineer A.F. Wigram. The feasibility of the microwave route was checked out by Hanstock, first using a 1/2 inch Batholemew’s map and later physically by foot and sometimes by motorbike.
In 1958-1959, a Bill was passed to allow for erection of the five towers and purchase of land at Ferryhill and Woolmoor for repeater stations. After the Bill was passed by parliament, a contractor was appointed but delays and problems continued including the GPO reluctance to licence; purchase of land and other site problems; and local authority planning permission for towers.
Nonetheless, the system was completed and brought into operation in 1964. The radio equipment for the system, including this example used at Darlington, was made by Marconi Italiana of Genoa, Italy.
Later changes were made to the system in the late 1970s and it remained in reliable operation until 1989.
SHF Radio Terminal Type MH140B, Drg 1735, Serial 009. (19 inch rack containing 14 modules and klystron unit)
SHF Radio Terminal Type HH140B, Drg 1735, Serial 010, (Similar to above, but assembled with typical modules, not the original operating modules)
Supervisory Transmitter module, Drg 1758, Serial 008
Supervisory Receiver module, Drg 1759, Serial 007
Power Supply module, Drg 1760, Serial 007
Power Supply module, Drg 1653, Serial 0101
Three Small Rear Vent Covers
Five Large Rear Vent Covers
Forty-three assorted Miniature Valves in cartons