The British Admiralty B29 receiver was originally developed from the Marconi CR200 receiver in 1941. It  was a five tube TRF (Tuned Radio Frequency) design and had a frequency range of 15 to 550 KHz. The B29 incorporated two VR100 RF amplifiers, a VR99 detector/oscillator, two AF stages (6J5 and NR69) and a 5U4G rectifier tube. A narrow, 1 KHz bandwidth filter was included in the audio stages for CW reception. It could operate on 120/220 VAC 50 Hz or battery power sources.

 
Modes: CW/MCW/Phone
Power input - 100/110 or 200/220 VAC, 50 Hz @ 33 watts.
Weight - 82 pounds. (?)
Dimensions - 19 x 13.5 x 16 inches.

B29 receiver in the distinctive blue colour of the British Admiralty. (Photo by Ray Robinson VK2ILV)

Click on the image to see the front panel details. Of interest is the front panel control called RIS. The abbreviation means Radar Interference Suppression and is used to reduce interference from ship's own radar transmitters. When RIS is not needed it needs to be in the OFF position otherwise the receiver's performance will be impacted.  (Image courtesy British Admiralty)

 

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Contributors and Credits:

1) B29 data sheets from the British Admiralty.

Oct 3/12