Rebecca Mk IIA Indicator Range Scale Part of BC929

The range scale is mounted over the face of the 3BP1 CRT of the BC929 Rebecca indicator unit. It is clamped to the aluminium bezel of the display by a metal ring held by 4 screws, and the inside of the ring is faced with felt to protect the glass screen of the CRT. The scale is made of transparent green plastic, printed with a rectangular graticule indicating the range to the Eureka transponder in nautical miles. The 50 nautical mile range is read on the left vertical axis, while the 10 and 100 nautical mile ranges are read on the right one.

Received transponder signals cause horizontal deflection of the timebase sweep from the central vertical axis of the scale. By means of a Rebecca Signal Switch in the BC929, leftward deflections are assigned to the antenna system on the port side of the aircraft and rightward deflections to that on the starboard side. Morse code can be transmitted at a low rate by varying the width of the response pulses. The display on the scale is interpreted by the radar operator, who transmits the information to the pilot verbally.

Here you find 398 models, 350 with images and 210 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from MILITARY U.S. (different makers for same model)