Alister J Mitchell GM3UDL
Originally, this page described a particular piece of World War 2 communications kit, the Wireless Set, Sound Ranging, Mk2 - a very rare item about which Colin Guy, G4DDI had written an article some years ago for VMARS, currently found here. This was to be the beginning of a three year investigation which led me through some fairly esoteric backwaters and proved that the Radio Link SR Mk2 was by no means either the beginning of the story, or the end.
The first thing I discovered was that location of enemy gunfire by soundgoes back to around 1910 in Russia, but that used the "flash to bang" time and although it produced acceptable results for the time, it was not accurate. The credit for the invention of accurate sound location goes to William Lawrence Bragg, later Sir Lawrence, who was serving in the the Royal Horse Artillery noticed an interesting phenomenon whilst sitting on the privvy!
Hand in hand with Sound Ranging goes Flash Spotting, which relies on accurate bearings on gun flashes taken from several locations. This was perfected by a Canadian officer, Harold Hemming, at around the same time as Bragg was working on SR.
I have consulted a number of members of the Wireless-Set-No19 email group, read a great many training documents, revised my university Trig 101, and visited two wonderful libraries, the Royal Artillery Archive in Woolwich Arsenal and the National Archive at Kew, both in London. In the course of my reading, as must always happen, I've found tantalising hints of dozens of other areas of research which could be pursued by someone interested in military communications. But I stuck to the task in hand and over the three years have put together what I hope is an interesting story. which may be downloaded from the link below - there is no password.
Alister Mitchell 27/5/2007
The article contains many pictures relating to Sound Ranging and Flash Spotting but we have some additional pictures of the Radio Link, SR, Mk2 which you may like to see. Cick on the thumbnail to see the full size image:
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OS Set Front |
OS Set Interior Top |
HQ Set Front |
HQ Set Interior Top |
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OS Set Plate |
HQ Set Plate |
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OS Set Front |
OS Set Front |
HQ Set Front |
HQ Set Front |
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OS Set Detail |
OS Set Detail |
HQ Set Underside |
HQ Set Underside |
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OS Set Underside |
OS Set Underside |
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| Power Supply | |||
| Pictures from Walter Cista, IW7EEY | |||
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HQ Set Front |
HQ Set Front |
HQ Set Front |
HQ Set |