The RCA SRR-13A is a dual conversion superhet that covers 2.0 to 32 MHz. It uses 29 tubes that are soldered into removable modules, not plugged into sockets in the conventional manner. The radio is unusual not only for its highly modular construction, but for a an optically projected frequency readout. It weighs 69 pounds but seems heavier.....
The RCA SRR-11, 12, 13 and 13A were designed for general shipboard use by the U.S. Navy. Two related series of receivers, the FRR-21/22/23 for fixed use and the MRR-1/2/3 for mobile use, are very similar in design and appearance. The more specialized FRR-18 and 19 used crystal controlled local oscillators. The receivers were manufactured by RCA and Magnavox (for RCA) from 1949 through 1960.
All receivers in the series are dual conversion superhets, with IF frequencies of 60 and 200 KHz for the SRR-11 and 200 and 1600 KHz for the SRR-12, 13 and 13A. Both the SRR-11 and 12 revert to single conversion (200 KHz IF) for 3 of their 5 bands; the SRR-13/13A are always dual conversion. The SRR-11 has 28 tubes; the 12 and 13 have 29 each. The frequency coverage, over 5 bands, of each model is:
Model Low High
SRR-11 14 600 kHz
SRR-12 0.25 8 MHz
SRR-13 2 32 MHz
Jerry Proc has some data related to SRR/FRR use in the Canadian Navy.
Some closely related FRR/MRR/SRR VLF, MF, and HF receivers.
Not related (closely, anyway) to the multiple rack, two ton FRR-24, FRR-37, or FRR-10.
Lots of information on US Navy receivers of the 1950's and 1960's at Nick K4NYW's web site.
NAVSHIPS 91875A, Technical Manual for Radio Receiving Sets AN/SRR-11, AN/SRR-12, AN/SRR-13 and AN/SRR-13A, 2 October 1953 w/ changes through 20 July 1961. (NAVELEX 0967-LP-115-2010)
NAVSHIPS 92211, Technical Manual for Radio Receiving Sets AN/FRR-21, AN/FRR-22 and AN/FRR-23, Change 1.
"Communications Receivers, The Vacuum Tube Era 1932-1981", 3rd Edition, by Raymond S. Moore
AN/FRR-23 (Courtesy Jon Pevner)
AN/FRR-21 VLF Receiver (Courtesy Kazu Okunishi)
AN/FRR-21 Dial close-up
The pile of manuals (Courtesy Kazu Okunishi)
The elusive CG-1101/FRR umbilical/test cable
AN/SRR-11 projected dial closeup (courtesy Tom Norris)
Perspective view of the SRR-13. 62K GIF.
Labelled front panel view of the SRR-13. 86K GIF.
Additional SRR series reciever images from Google Image Search
The Holy Grail! The CG-1101/SRR Test Cable
Replacement Parts? Some are still made by the original companies! For others, make your own!
Pesky Switch Arms, hard to find parts used in mode and band switch linkages.
Tuning capacitor coupler repair
Lots of rack mount radios have dull, lifeless handles that are merely screwed into the front panel. Not SRR-13's! They have kinetic handles with handle gears. What the heck are handle gears? Why, the gears that gently extract the radio from the case when you rotate the front handles upward. And when those handle gears wear out, buy some original replacement parts.