TV cable across Atlantic? 

18 November 2020 tbs.pm/71427

 

The Evening News masthead

From the Portsmouth Evening News for 20 January 1955

COMMUNICATIONS experts in New York believe that, although it is not at present technically feasible, a Transatlantic television submarine cable could be developed if there were sufficient demand for it.

They believe that such a development would take much less time than the 35 years taken by scientists to make it possible to lay the world’s first submarine voice cable.

“No-one will say that it is not possible to lay a Transatlantic television cable,” one industry spokesman declared. “Things which we dreamed were not possible 25 years ago are accepted as commonplace to-day. The important thing is the urge to have it. If someone wants it badly enough some day it will probably be done.”

Questions about the possibility of Transatlantic television were prompted by remarks made recently by an official of the Bell Laboratories in a radio talk about the new Transatlantic telephone cable, laying of which is to begin next summer.

The Bell official, Mr. Ken Honaman, discussing the technical developments which made the new cable possible, told his audience that the “key” to the success of the project would be 104 electronic repeaters spaced at 40-mile [64km] intervals across the ocean floor. These would boost power along the 2,000-mile [3,219km] cable and make possible reception as clear as an ordinary inter-city telephone call. Bell Laboratories developed the repeaters.

Two cables

Bell System trademark

Later, Mr. Honaman told Reuter that there would actually be two cables. For a conversation between New York and London, for example, he explained, one cable will carry the voice of the person in New York and the second will carry the voice of the person in London.

Under this system, 35 other conversations could be carried on at the same time, in the same way.

The “shore-end” – 200 miles [322km] long – will be laid out from Newfoundland to the end of the Continental shelf and bouyed. Then the British cable-laying ship Monarch, the world’s largest, will start laying out the 1,600 mile [2,575km] long deep-sea section.

The cable is expected to rest three miles [4.8km] down on the ocean bottom, where pressure is estimated at 5,000lb per square inch [345 bar]. About 200 miles from Scotland, this cable will be hooked on to the other “shore end.”

In the summer of 1956, the second cable, from east to west, will be laid, and officials hope that it will be in operation late next year.

 


 

❛❛Russ J Graham writes: This article drifts confusingly between talking about the theoretical transatlantic television cable and the actual practical transatlantic telephone cable being laid at the time, but it’s still worth unpicking it.

The history of these types of cables goes back far longer than most people would imagine – to the 1850s. The telephone cable being laid as the article was being written was TAT-1, which carried 35 telephone calls and 22 telegraph messages at a time. It opened to traffic on 25 September 1956.

 

A map of cables crossing the Atlantic

A map of cables crossing the Atlantic from 1858; public domain image sourced from History of the Atlantic Cable & Undersea Communications

 

By 1978, there were 7 transatlantic telephone cables, with three terminating in Britain. But they were all telephone connections: the costs of laying a cable exclusively for television, which might not even get used for weeks during slack news periods, made it uneconomic; the arrival of satellite television (the periodic Telstar in 1962, the geosynchronous Early Bird in 1965) made them unnecessary.

 

Courtesy of Tom Scott

 

Modern transatlantic cables are fibre optic rather than copper co-axial, and multiplexing and various compression algorithms now make it possible to carry television pictures between the two continents. Nevertheless, satellite remains the dominant way of exchanging newsfilm and other items of international interest, whilst the cables carry our voices and the internet.

A Transdiffusion Presentation

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