Wireless Set No. 11
The No. 11 Set, a radio tranceiver featuring a single tuning unit, was designed in 1938 to replace the 1933 No. 1 Wireless Set. Originally designed to be used in tanks for short to medium range communications, it was later used by the Long Range Desert Group in Libya and Tunisia for long range communications while deep behind enemy lines. The Germans reportedly "captured several sets in France" and put them to use for their own communications needs. 
- Power: Batteries or 6V or 12V mains supply
- RF output: 0.6W to 4.5W
- Communication range: Approximately 3 to 20 miles (4.8 to 32.2 km) using 6-foot (1.8 m) or 9-foot (2.7 m) aerials.
- Dimensions: 8.5 by 19.5 by 12 inches (220 × 500 × 300 mm)
- Weight: 43 pounds (20 kg); complete Low and High Power stations weigh 180 pounds (82 kg) and 216 pounds (98 kg).
- Control: Direct or remote, enabling operation at 400 m (440 yd) and a remote aerial at up to 10 m (11 yd)
- frequency range 4.5 to 7.1 megacycles
- http://www2.armynet.mod.uk/museums/royalsignals/wirelesssetno11.htm Royal Signals Equipment