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The S-Phone system was a UHF duplex radiotelephone system developed during
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The S-Phone system was a UHF duplex radiotelephone system developed during World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
for use by Special Operations Executive
The Special Operations Executive (SOE) was a secret British World War II organisation. It was officially formed on 22 July 1940 under Minister of Economic Warfare Hugh Dalton, from the amalgamation of three existing secret organisations. Its pu ...
agents working behind enemy lines to communicate with friendly aircraft and coordinate landings and the dropping of agents and supplies. The system was composed of a "Ground" transceiver, designed by Captain Bert Lane, and an "Air" transceiver designed by Major Hobday, both of the Royal Signals
The Royal Corps of Signals (often simply known as the Royal Signals – abbreviated to R SIGNALS or R SIGS) is one of the combat support arms of the British Army. Signals units are among the first into action, providing the battlefield communi ...
.
Description
The "Ground" set - which was to be used by agents on the ground - weighed about including batteries and was typically worn attached to its operator with two canvas straps. It was a highly directional unit which required the operator to face the path of the aircraft. It had the useful trait that transmitted signals could not be picked up by ground monitoring stations more than one mile distant; however, its signal was only good to , which brought the aircraft within range offlak
Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based ...
. It permitted direct two-way voice communication with an aircraft up to a range of . While the S-Phone provided directional information to the pilot it gave no range information, although a pilot could tell when he was directly over the "Ground" operator because at that point no communication was possible.
The primary purpose of the S-Phone was not navigational as such; rather, it was to provide a reasonably secure channel for coded conversation between staff officers based in London and agents in the field, allowing for the exchange of orders and information. The security of a circuit was sometimes tested by using an officer who could recognize whether a voice was actually that of the agent who was supposedly speaking to him.
It was designed in late 1942, using some of the component parts of the Wireless Set No.37.Wireless for the Warrior, Volume 1 Wireless Sets No. 1 - 88, Louis Meulstee, G. C. Arnold Partners 1995, {{ISBN, 1-898805-08-3
Use of the phone is shown in the post-war docu-drama '' Now It Can Be Told'' (aka School_for_Danger, 1946) oYouTube
See also
Joan-Eleanor a similar system developed for the OSSSpecifications
General
*Frequency: 337 MHz (TX) / 380 MHz (RX) *Output Power: 0.1 to 0.2 WNotes