The Aldeburgh-Domburg No. 4 Cable
This was a co-axial type cable manufactured and laid by Submarine Cables Ltd. The cable was laid by the cableship
Faraday and the Dutch vessel MV Pallas.
This cable, and the Aldeburgh-Domburg No. 5 cable, were the first of their kind to be laid to the Continent. They were an entirely new departure from the previous submarine cables in that they consisted simply of one central copper conductor of 0.138 inch in diameter running concentrically through a tube of 0.62 inch in diameter formed of copper tapes and filled with paragutta insulation.
Previously the number of telephone circuits provided by a cable had been determined by the number of conductors it contained, but this new type carried the separate telephone conversations on different frequencies, similar to the way that different radio programmes are transmitted on different frequencies, and these had to be separated at the distant end of the cable by equipment similar to a group of radio receivers, each permanently tuned to pick out one particular conversation. Such a technique is known as carrier telephony and is an example of Frequency Division Multiplexing (FDM).
The No. 4 cable was used in conjunction with the No.5 cable, to provide go/return paths. Initially, the pair of cables carried 16 channels with provision for emergency operation of 5 channels over one cable. The 16 channels were provided by two separate carrier systems, one occupying the range 200 Hz to 16 kHz and the other the range of 16 kHz to 60 kHz. 5 channels were provided in the lower frequency band, the equipment being of the Post Office Carrier System No. 4 type (4 + 1 channels). The equipment occupying the upper frequency band was of the Post Office Carrier System No. 5 type (12 channels, of which 11 were used).
The Carrier System No. 4 was designed and constructed by the Post Office Research Branch, while the Carrier System No. 5 was manufactured by Standard Telephones and Cables limited.
Following the enemy occupation of the Netherlands in 1940, the TRS was closed and in May of that year, the Aldeburgh-Domburg No. 4 and Aldeburgh-Domburg No.5 cables (plus other cables which were in operation at that time) were cut on the beach and out at sea.
Following the invasion of Europe by allied forces in 1944, the station was reopened for military purposes and the submarine cables were repaired and the Aldeburgh-Domburg No. 4 and Aldeburgh-Domburg No.5 cables were equipped with military carrier systems.
After the war, the Aldeburgh-Domburg No. 4 and Aldeburgh-Domburg No.5 cables were re-equipped to provide a 24 channel four-wire carrier telephone system.
in 1950, 4 submerged repeaters were inserted into the Aldeburgh-Domburg No. 4 cable. Together with new terminal equipment this provided 60 circuits on the cable.
Further information to be added soon.
Page last updated 28th December 2014.