RCA RAB Receiver

An Exercise in No-Holds-Barred Receiver Design  Ca. 1931

This is an ongoing investigation.  Any information on the history of this radio would be greatly appreciated.  This information is from the instruction manual dated 30 June 1931.

The United States Navy became one of the early adopters of long-range short-wave communications as a result of positive results obtained during fleet maneuvers in 1925.   Early receiving sets were TRF-autodynes, but by the early 1930's the state of the art had progressed far enough to allow the design of a truly effective super-heterodyne for the HF range.  The RAB was probably the first mass-produced short-wave superhet, and had a number of advanced features that would not appear in commercial sets for years.

Model RAB Radio Receiving Equipment
  • Range 1,000 - 30,000 KC in eight band-switched ranges
  • 2 Tuned RF stages for effective image rejection
  • 2 IF stages with 8 tuned circuits for a modicum of selectivity.
  • IF frequencies:  600, 1450, 3250, 7200 KC  The higher IF's ease the image problem at higher frequencies, and widen the bandwidth to compensate for transmitter instability.
  • IF frequency depends on band in use
  • Remote-cutoff tubes in RF and IF for excellent manual gain control
  • Regulated PS for LO and BFO
  • Audio filtering for AM and CW
  • Audio limiter (AVC)
  • Weight:  455 lb (plus table and typewriter)

RF Tuner CRV-4552 
(rear view)

RF and oscillator coils are mounted on the top and bottom of the main chassis.  Band selection is accomplished by a sliding assembly containing the five-gang tuning capacitor and tubes.  This carriage is moved by a lead screw actuated by the milling-machine-like knob on the front panel.

IF and AF Amplifier CRV-4553

Four sets of IF transformers and BFO coils are mounted on the underside.  IF frequency selection is by way of  a sliding chassis containing the tubes and support circuits.

RAB_schematic.gif (188KB)

RAB Manual (11MB)