Calling the Empire!

A 16.6 kilohertz long wave transmitter, for wireless telegraphy, for signalling all parts of
British Empire !

I came across this amazing article whilst browsing in the basement of the Monash University Hargrave Library. It was in an ancient bound volume of Proceedings of the British IEE.  I suspect this volume has lain undisturbed for many years. There are some real gems in this collection but this is true steam radio.  This transmitter , as you will read , was constructed to permit wireless telegraphic from the British Isles to all parts of the Empire, and with sufficient power , to be plainly audible day and night.  I expect that it was also biult with submarine warefare in mind, not to mention the requirements of the Admiralty to signal British warships, anywhere on the globe.  It would have been justified in the light of experience with long transnational telegraph and their vulnerabliltiy in time of war.  World War One had been concluded only a few years before this project was conceived.

The images of this journal extract were taken with a small Pentax camera in poor light in the library basement. The fat pudgy fingers are mine!



This was the state of the art in 1926. Most remarkable !

Having just read all that, here are my thoughts.  This was 16Khz, some of the people working here would have been able to hear this!
All day long. Not just the squeal of it, so you could block it out, but this was telegraphy, you could not escape it. The article mentions that there was an off air monitor, a loudspeaker, just so that the duty engineer could here this squeal and "know that all was well".  The article mentions that its design was also to permit single sideband voice modulation, a one transatlantic wireless telephone circuit. I wonder how much a minute of talk time would have been billed for.  This experience is mentioned in other articles in this timeframe. Single sideband must have been like black magic then.  Have a look at the primary frequency standard, a tuning fork. Maybe the operator engineer could have heard if the transmitter was off frequency!   The followup discussion mentions the reliability of vacuum tubes and concerns that there were too many of them in this design.  My question is, given the low frequency, why wasnt an Alexanderson Generator used ? No use for voice but certainly satisfactory for telegraphy.  I wonder for how long this service persisted.  The discovery of short wave propagation would have followed shortly after this station commenced operation.  The article does not mention what this cost to construct and operate but it was not pennies!  It was also interesting to read the special precautions taken to ensure that this station did not interfere with other broadcast services.

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