Paraset

The radio Mk VII for equipping British illegal intelligence agents was developed in 1941 at the MI-6 radio center, Whaddon in Buckinghamshire . The name "Paraset" is most likely unofficial, derived from the words "parachute" and English. set - installation, set (the English radio was then officially called English. Wireless set - wireless installation ^[1] ). The development was led by engineer Dennis Smith. In 1942, Weddon workshops manufactured about 20 walkie-talkies of the Mk VII for testing. In 1943, they began mass production (hundreds of copies) at the Little Horwood plant. The first series were made in wooden cases, later switched to metal. The technical documentation of the Paraset was not preserved (the documentation for the special equipment of the times of the war was destroyed by order of W. Churchill ), therefore there are no complete and reliable data on the device and characteristics of the Paraset. Valuable information was retained at the time by the late Belgian ham radio operator Ioe le Suisse, callsign ON5LJ. Some details about the creation of the walkie-talkie are known from its participants - former employees of the Weddon radio center. Amateurs did a lot of exploratory work, nevertheless, there were discrepancies in the scheme and design details of the radio. There were probably several variations with minor differences.

The small transmitter power was sufficient so that signals from the continent - from France , Belgium , the Netherlands - could be confidently received in Weddon. It all depended on how high-quality the antenna the agent could deploy. In addition, in the mid-1940s. a maximum of solar activity was observed, which facilitated long-range communication at short waves. The Paraset receiver was regenerative, and for receiving telegraph signals it had to be entered into the generation mode, that is, the walkie-talkie emitted a radio signal even in the reception mode. This circumstance could facilitate the enemy direction finding of an illegal radio station. However, measurements show that the Paraset’s level of this spurious radiation is very small due to its well-thought-out design.

The Whaddon Mk VII radio station is short-wave, telegraph , simplex , battery powered, on three octal radio tubes with a metal cylinder. Separate receiver and transmitter are mounted in one case (wooden or steel ). All controls, lamp panels, a quartz resonator socket, power terminals and antennas are located on the panel under the hinged cover of the case. In the idle position, all lamps are removed from the panels and fixed under the cover on the holders. The dimensions of the steel case are approximately 230 × 140 × 120 mm. The whole set with a power source and accessories was placed in a small suitcase and weighed several kilograms.

Direct amplification receiver with a regenerative detector and one low-frequency amplification stage (0-V-1), on two lamps (6SK7 pentodes ). It works in the range of 3.2 ... 8 MHz with smooth tuning.

The transmitter is a 6V6 beam tetrode oscillator , operates at fixed frequencies within 4.5 ... 7.6 MHz with quartz stabilization. Quartz resonator is replaceable. The type of work is amplitude manipulation . The output power is about 5 watts. A telegraph key is integrated in the transceiver case.

The antenna used was usually a single wire about 20 m long.

The power source is a 6-volt battery and a vibration converter . An AC power supply was also produced.

The receive-transmit switching is performed by applying anode voltage to the lamps of the receiver or transmitter, respectively, and by switching the antenna.

In the UK and other countries there are many enthusiasts who restore the preserved copies of the Parasets, and more often build copies ( replicas ) more or less appropriate to the original and work on them on the air . The missing parts of the sample of the 40s are made anew or mask modern components under them. There are even replicas in which transistors are hidden in the dummy lamps. ^[2]

At least three active replicas built in Russia are known (Alexander Krylov, UA3IPS, Bezhetsk ; Oleg Chernov, RV6HTZ, Nevinnomyssk ; Rafael Nazmutdinov, UB4PMD, Naberezhnye Chelny ), and one in Ukraine (Alexander Naumov, UT4FJ, Odessa ) ^{[3 ]} . They are assembled on Soviet analogues of the original lamps - 6K3 instead of 6SK7 and 6P9 or 6P6S instead of 6V6.

• North (radio station)
• Amateur Radio
• QRP

• Louis Meulstee, Rudolf W. Staritz. Wireless for the Warrior. Volume 4. Clandestine Radio. - Wimborne Publishing Limited, Ferndown, Dorset, UK, 2004, ISBN 0952063 36 0 [1]
• Bob Kellogg AE4IC. A Short History Of The Paraset.// QRP Quarterly, 2009, Issue 4, P. 43
• Bob Kellogg AE4IC. Making A Replica Of The Paraset.// QRP Quarterly, 2009, Issue 4, P. 42
• Dabbs Simon . Building a Replica Paraset.//SPRAT, # 129, P. 28-31

• The Whaddon Mk VII - Paraset Clandestine Radio - A Brief History
• VV Babievsky et al. World War II: Agent Radio
• Paraset no 2357 - detailed photos of the original walkie-talkie
• The Paraset Club - British club of lovers of Paraset (registration required)
• www.paraset.co.uk - a lot of information about the original and recommendations for building replicas
• WA4MNT Paraset Project
• Homemade pages from different countries:
  • The VE7SL Radio Netbook. Building A 'Paraset' (Canada)
  • The Paraset Project. How to make a replica Norwegian Style. (Norway)
  • My Paraset (USA)
  • M6ATD PARASET (UK)
  • PARASET Valise de la résistance (France)
  • The Whaddon Mk-VII, aka The Paraset: clandestine or spy radio (Netherlands, detailing the production of a replica, including dummies of radio parts of the 1940s)
  • NY4G Weblog. Paraset Replica Project - Bayou Jumper (USA, transistor replica reproducing the original only externally)
  • Belgian replica of Paraset in action. on YouTube
  • Brazilian replica of Paraset, in detail. on YouTube