The Radar Room

WHADDON PARASET COVERT TRANCEIVER      (transmitter and receiver)

Original Paraset less valves

An original Paraset - less the three valves and crystal

Paraset was one of the many types of covert radio dropped by parachute behind enemy lines for use by the resistance. The Paraset was unlike most of the other types as it also incorporated a transmitter section to allow two way communications in morse code. The circuit was simple but effective. Two valves for the receiver and a single valve for the transmitter. The range of the later (with a good length of aerial wire) was easily several hundred miles in average conditions.

The Whaddon Paraset was used for clandestine radio communication primarily in Norway and Europe. It was developed at the Royal Signals Special Communications Unit workshops at Little Horwood and the workshops of Whaddon Hall, Buckinghamshire. The name “Paraset” was used because it was normally dropped by parachute for field agents of the resistance.

The ‘Paraset’ is still well known today as many radio amateurs have constructed replica instruments, using the same circuit, components and panel layout. These are regularly used by some for amateur radio transmissions. The Paraset seen at the Radar Room is a fully functioning replica and can usually be heard by visitors to demonstrations tuned into a short wave morse transmission on a period headset for authenticity.

Paraset in a briefcase

An original Paraset fitted into a briefcase

Note that the Paraset uses three of the American black-painted rugged ‘metal’ valves. Two 6SK7 ‘RF pentodes’ for the regenerative receiver and a single 6V6 ‘beam tetrode’ for the transmitter.

If you’re into making electronics projects, then how about considering a replica Paraset?  You’ll find a wealth of helpful material on-line today if you do. The basic but complete circuit is shown below. Coil details etc. can be found online if you want to have a go at building one.

Reminder- You WILL need to have passed the Amateur Radio Examination with morse to legally use the transmitter section. You’re free to use the receiver part without one of course!

Paraset schematic
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