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 sound goes
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 and 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 five years have put together
what I hope is an interesting story, which may be found by clicking the link
below - there is no password.
Alister
Mitchell 24/5/2009
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. Click here to see a thumbnail index of
these photographs.
The article also refers to many source documents, some of which I have collected
over the years and which are listedon various pages in the archvie the archive.
For convenience, I've brought them all together in the following table. All
of these documents require passwords, as on the rest of the site.
Cick on the thumbnail below to see the full size image:
|
OS Set Front |
OS Set Interior Top |
HQ Set Front |
HQ Set Interior Top |
|
OS Set Plate |
HQ Set Plate |
||
|
OS Set Front |
OS Set Front |
HQ Set Front |
HQ Set Front |
|
OS Set Detail |
OS Set Detail |
HQ Set Underside |
HQ Set Underside |
|
OS Set Underside |
OS Set Underside |
||
| Power Supply | |||
| Pictures from Walter Cista, IW7EEY | |||
|
HQ Set Front |
HQ Set Front |
HQ Set Front |
HQ Set |