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Charles Bovill

Charles Bovill (18 February 1911 - 9 May 2001) was an electronics engineer and inventor who lived in England (UK). During WWII, he worked for the Special Operations Executive (SOE), for which he invented devices like Rebecca and the S-Phone. During the 1970s and 80s, he became known for his invention of the non-linear junction detector (NLJD), also known as the Broom.

The Broom was first sold by Allen International Ltd. in Westminster (london, UK), which was a front operation of MI6. Allen International was a subsidary of Technical Services Ltd., another MI6 front, operated by his friend and colleague Lee Tracey, the inventor of the Scanlock bug tracer.

Another invention of Bovill was the Photic Drive, a device that could be used for crowd-control. It produced a combination of sub-sonic waves and strobe light, and caused acute discomfort, disorientation and sometimes epilepsy. In his laboratory at West Byfleet, he tried it on his wife.
Charles Bovill in the Channel 4 documentary 'The Walls Have Ears' [2]

On 1 October 1973, he nearly lost his live when the IRA, afraid that this device would be used against them, wanted to place a bomb in his Westminster office. Fortunately, the person placing the bomb was spotted on camera by Bovill's colleagues, and eventually the bomb didn't go off. The Photic Drive was later marketed in the US, where it was successfully used against prison riots.

Bovill's inventions on this website
Full duplex UHF radio for resistance communication and air droppings
Non-linear junction detector, used for finding bugs even if they are switched off
Eureka beacon
Charles Barton Bovill was born 18 Febrary 1911 at Battersea, south London (UK). He was educated at Bedford School, the University of Grenoble (France) and the Regent Street Polytechnic (London), after which he joined HMV as a radio engineer in 1933. In 1935 he made the move to the Air Ministry, where he worked in the wireless telegraphy section, and three years later to Marconi.

During WWII, Marconi lent him to RAF Bomber and Costal Commands, where he started working as a radio development engineer. His work was noticed by the Special Operations Executive (SOE), who recruted him in October 1941 for the Inter-Service Research Bureau (ISRB); a cover name for the technical research and development of the SOE. In April 1942 he became a flight lieutenant with the Technical, Signals and Radar Branch of the Royal Airforce Volunteer Reserve. In order to find corroded parts on airplanes, Bovill developed the non-linear junction detector (NLJD).

Towards the end of the war, he briefly returned to the ISRB, which lasted until May 1945 when he became a civilian again and started working for Decca. In 1972 he became technical director of Allen International Ltd., a company with a shop above a bedding shop in Westminster (London) that specialized in miniature microphones, bugs and other spy equipment. According to friend and colleague Lee Tracey, Allen International was a cover for certain MI6 activities, just like his own company Technical Security Ltd [4]. For several years, Allen International supplied the Q-type gadgets for the famous James Bond movies. When the shop was closed down in the mid-1970s, the activities were taken over by yet another MI6 front: Security Research Ltd. in Guildford (UK).

In 1999, Bovill appeared in the fascinating Channel 4 documentary The Walls Have Ears [2] in which he demonstrated the original Broom in the shed behind his home. The Broom is a device that is able to locate (radio) bugs, even when they are switched off. It is based on his wartime development of the non-linear junction detector. During WWII it was used to find corroded airplane parts, but Bovill discovered that it could also be used to find other semiconductors, such as diodes, transistors and ICs. The image above was taken from that Channel 4 documentary [2]. Just two years later, on 9 May 2001, Charles Bovill passed away at the age of 90.

Invention of the NLJD
In some literature, the Russians are credited for inventing the Non-Linear Junction Detector (NLJD), as they came up with an equivalent device around the same time as Charles Bovill did in 1972. However, as Bovill already used the NLJD during WWII to find corroded parts on airplaines, we assume that he is the original inventor. It is quite possible though, that the Russians invented it completely independently, or that they had information about Bovill's secret wartime work.

 More about the NLJD

Known inventions
  1. The Telegraph, Charles Bovill, Obituary
    9 May 2001.

  2. Channel 4, The Walls Have Ears
    Fascinating Channel 4 documentary about The Spying Game - The Walls have Ears.
    1999. Via YouTube. Interviews Glenn Whidden, Lee Tracey, Charles Bovill and others.

  3. Bernard O'Connor, Charles Bovill, WW2 Radio expert
    e-Book. 44 pages. Retreived May 2013.

  4. Lee Tracey, Interview and personal correspondence
    Crypto Museum. 23 May 2013.
Further information
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Crypto Museum. Created: Thursday 17 September 2015. Last changed: Sunday, 01 January 2023 - 12:36 CET.
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