Marine Radio c.1965

Electrical and electronic topics for small boats
jimh
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Marine Radio c.1965

Postby jimh » Wed Apr 19, 2017 8:57 am

In 1965 British Telecom produced an elaborate 22-minute color and sound motion picture presenting their coastal radio communication system, which they summarized as follows:

The work of the men of the coastal radio stations around Britain who, twenty-four hours a day, maintain vital links with ships at sea. The film highlights this little-known service of British Telecom by showing how a listening watch is kept throughout the day and night for any faint call of distress on the emergency frequency. It stresses the humanitarian aspects of the medical service in which doctors and ships co-operate, and touches on the more routine tasks - messages for ships, information about weather, positions, navigational hazards - and all the problems, practical and human, which concern men and ships in the busy sea lanes and coastal waters around Britain.


This is a delightful retrospective on the days of marine radio communication using mostly medium-frequency or high-frequency voice and morse code in an era of elaborate shore stations, patching of radios into land telephone circuits for ship-to-shore telephone calls, and fishing boats of modest size. No digital selective calling, automatic identification system, or satellite telephony in use back then; no monster fishing vessels with their own processing plants. But delightful shore stations with operators with local accents, turning dials and throwing lever-arm telephone-type switches on big metal panels with lots of pilot lamps. The film is quite entertaining, and gives many views of the state-of-the-art in radio c.1965.

Here is the link:

https://bt.kuluvalley.com/view/dFrkWeoskh5

This reminds me of the early days of my own coastal cruising in Georgian Bay in the 1980's, before cellular telephones, when you'd call up the marine operator and place a telephone call to home to let everyone know you were still afloat and having a good time.

There are plenty of shots of marine radio gear, mostly Marconi, Mackay, RCA, or perhaps Telefunken. The antenna farm is also shown, with cows grazing nearby. There are cage-dipole antennas with the wire spreaders arranged in a six-pointed hexagram star (or "Star of David). (Cage-dipoles increase the effective diameter of the radiating element and give much improved bandwidth.) And, best of all, when morse code is being heard and an operator is transcribing the message, the actual code heard matches what the operator is writing down. That almost never happens in motion pictures.

The beautiful P&O England-to-Australia liner SS CANBERRA has a cameo role in the film, with a passenger calling his stock broker using the "privacy" circuit, which sounds like it employed inverted sideband for scrambling the audio.