The Paraset was a small, low-power, thermionic valve, CW-only radio transmitter-receiver supplied to the resistance groups in France, Belgium and the Netherlands during World War II.Armement Clandestin, France 1941-1944 by Pierre Lorain, 180 pages, Publication date: 01/01/1972.
History The Paraset was one of the first successful miniaturized radio sets for Britain's Special Operations Executive which conducted espionage and other underground activities behind German lines during World War II.The Paraset Radio The story of a WWII Spy-Radio and How to Build a Working Replica By Hiroki Kato, AH6CY,
The set, known as the Whaddon Mark VII, was used for clandestine radio communication primarily in Norway and Europe, developed at the Royal Signals Special Communications Unit workshops at Little Horwood and the workshops of Whaddon Hall, Buckinghamshire under advice from Lieutenant Colonel Frederick W. Nicholls (SOE Director of Signals) in the early stages of World War II. The equipment is known as the "Paraset" because it was dropped by parachute insertion for field agents and resistance cells.
A number of amateur radio operators build and operate replicas of the Paraset.
Features Independent Tuning: The transmitter frequency was fixed by inserting a specific quartz crystal into the top panel. The operator could then freely tune the receiver across the band to listen for incoming signals. No Volume Control: To adapt to the bare-bones setup, operators adjusted the volume simply by physically shifting the headphones over their ears.
Risks The "Leaking" Danger: Because it used a basic regenerative receiver design without an RF pre-amplifier, the radio accidentally leaked an oscillation signal through the antenna even while just receiving. This signal could be picked up by German radio direction-finding (RDF) vehicles. 5-Minute Rule: To avoid capture by RDF vans, agents were strictly instructed to keep their transmission sessions under five minutes.
Specifications Transceiver Type: Vacuum tube (valve) transmitter and receiver with independent circuits. Mode: Continuous Wave (CW) only, meaning it operated exclusively via Morse code. Dimensions: 222 x 142 x 110 mm Valves (Tubes): Three in total—two 6SK7 metal tubes for the regenerative receiver (detector and audio amplifier) and one 6V6 power tube acting as the crystal oscillator for the transmitter. Weight: 2.3 lbs / 1.04 kg Variants: Mk VII In wooden enclosure / Mk VII/2 In metal enclosure Receiver coverage: 3.0 to 7.6 MHz, one band (spanning the 40-meter and 80-meter amateur radio bands). Transmitter coverage: slightly more than 3.0 to 7.6 MHz, two bands, selectable. Power output: 4 to 5 watts. Power Source: Powered via AC mains or a 6V/12V vehicle battery paired with a noisy "vibrator" power pack to step up the voltage. Operated with a long-wire antenna and a ground connection.
Transmitter Modulation: CW Frequency: 3.3 - 7.6 MHz Ranges: (1) 3.3 - 4.5 MHz, (2) 4.5 - 7.6 MHz Output: 4 - 5 W Circuit: Oscillator/PA Valve: 6V6 Morse key: Internal only HT: 360V, 40-50mA
Power Supply Unit Input: 110 - 240V AC (6 steps), 40 - 60Hz Current: LT: 950mA, HT: 10mA (RX), 40-50mA (TX) Valve: 6X5 (rectifier) Dimensions: 114 x 110 x 110 mm Weight: 2700 g / 2.7kg
Main Components MK VII (Paraset) Headphones (high impedance) Antenna wire Ground wire Power supply unit Power interconnection cable Crystals Spare parts
Users : Belgian Resistance : French Resistance : Dutch Resistance Ordedienst (OD) / Dutch stay-behind (Cold War) : Norwegian Resistance : Special Operations Executive (SIS, MI6)
See also Amateur radio homebrew List of amateur radio transceivers QRP operation Vintage amateur radio Military Wireless Museum in the Midlands
References
External links
RADIO SET Mk. VII "Paraset" year 1941 Unveiling the Secrets of the Paraset Spy Radio G4BXD Original Paraset photo IK0MOZ Italian Paraset Project Paraset.nl Paraset project and info from The Netherlands AE4IC PARASET - World War II Spy Transceiver WW2 Paraset Transceiver Project Guide Paraset WW2 SPY Tranceiver