Navy HF Diversity Receiving Systems

Diversity systems use 2 or 3 receivers to copy the same traffic (typically CW or RTTY) from one or more transmitters
Frequency diversity - receivers tuned to different frequencies - to cover shifting ionospheric propagation
Spatial diversity - receivers tuned to the same frequency but connected to different antennas - to cover fading and multipath

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Many of these photos are of equipment that was for sale on eBay.
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HF Diversity Receiver Systems
model	type	primary use	freq	features
AN/FRR-3 AN/FRR-3A		Dual Diversity 2.4-23 mc HF Shore FSK Remote dial-up to select 5 fixed frequencies and 4 antenna combinations		manuf Press Wireless TM 11-872 Manual extract
AN/FRR-3 AN/FRR-3A				manuf Press Wireless TM 11-872 Manual extract
AN/FRR-10		Dual Diversity HF shore SSB (simultaneous USB & LSB) variant of FRR-24 click here for info	2-32 mc	dual diversity 253 tubes Manuf National info
AN/FRR-24		Triple Diversity HF shore RTTY & CW click here for info	2-32 mc	triple diversity 420 tubes Manuf National info/photos
AN/FRR-28 0.54-54 mc Dual Diversity - HF shore	two R-450/FRR-28 rcvrs O-165/UR master oscillator AM-615/UR amplifier/detector KY-79/UR keyer SB-224/UR patching panel LS-187/UR speaker	R-450/FRR-28 showing AVC switch and ID tags	uses two Hammarlund SP-600-MX (R-450/FRR-28) used with AN/URA-8A RTTY converter info SP-600 manuals FRR-28 spec sheet - page 1 FRR-28 spec sheet - page 2 FRR-28 at NAVCOMMSTA Kodiak 1959	More R-450/FRR-28 photos Manual - NAVSHIPS 91582 manuf - Northern Radio
AN/FRR-32			Dual Diversity - HF shore system 2-32mc two R-618/FRR-32 rcvrs (probably modified FRR-23) O-330/FRR-32 master xtal oscillator CM-70/FRR-32 comparator/keyer SB-431/FRR-32 patching panel LS-169/G speaker CY-597A/G rack	Manuf RCA NAVSHIPS 92736 manual pdf
AN/FRR-37		Dual Diversity version of FRR-24 HF shore RTTY & CW Click here for component info	2-32 mc	dual diversity approx 250 tubes Manuf National info/photos
AN/FRR-38		Dual Diversity FSK two R-390(*) receivers CV-116/URR dual FSK converter	0.5-32 mc FRR-38 and FRR-41 at NAVRADSTA ( R) Salinas	Signal Corps procurement but used by USN Manuf Collins & Hoffman TM-11-647 TO: 31R2-2FRR38, 31R-1-8
AN/FRR-41		Dual diversity SSB two R-390(*) receivers two CV-157 SSB converters (simultaneous USB & LSB from each)	0.5-32 mc FRR-38 and FRR-41 at NAVRADSTA (R) Salinas	Signal Corps procurement but used by USN Manuf Collins & others TM 11-649 TO: 31R2-2FRR-221
AN/FRR-42 AN/FRR-43	Subset of AN/FRR-24	Click Here for Info	-	-
AN/FRR-51	need photo	Dual-diversity HF with 10 channel auto-tune R-792/URR receiver (2 ea.) CU-560/URR antenna coupler C-2087/URR receiver control C-2086/URR remote switching control CV-116/URR FSK converter CV-395/U Signal Data Converter CY-1119/U cabinet	need info	need info - please send e-mail
AN/FRR-55	AN/FRR-55 was the Receiving Set portion of the AN/FRC-63 UHF Moon Bounce System
AN/FRR-55
AN/FRR-60(V)	photo from TMC vintage radio web site	HF shore diversity system NAVCOMMSTA Guam - 1960's	More Info - AN/FRR-60 Page	Manuf TMC Model DDR-5
AN/FRR-74		TMC-DDR-5K Similar to FRR-60 but with 4 ISB	spec sheet	--
AN/FRR-85		TMC DDRR-10 w/ remote tuning	spec sheet manual download	-
AN/URR-49	Guam 1968 - URR-49 configurations	HF shipboard/shore FSK dual-diversity system two R-390A receivers AN/URA-8A dual FSK converter	info needed	Nomenclature was assigned and this configuration was widely used both afloat and ashore, but I'm not sure it was ever procured as AN/URR-49
AN/URR-63	need to add photos	TMC DDRR-10 w/ remote tuning	manual download	-
AN/URR-64(V)	AN/URR-64(V)1 dual diversity (two receivers with two synthesizers)	AN/URR-64(V)2 single receiver More URR-64 Photos	AN/URR-64(V)3 dual space diversity (two receivers with one synthesizer	TMC model DDR-10 - photos thanks to www.tmchistory.org manual download Components TN-512/URR tuner TD-915/URR demultiplexer O-1511/URR freq synthesizer --
RAE	Pre-war triple-diversity HF unit using three RAB receivers	See RAB photos and info on WW2 Receiver Page	-	-
RBP RBP-1 RCP			1940's system 3-24 mc RBP is dual triple-diversity system (6 rcvrs) RCP is single triple-diversity system (3 rcvrs)	Manuf RCA RBP & RCP Page - spec sheets, photos, and downloadable manual
RDM (RCA DR-89)	Triple Diversity HF System using RCA AR-88 receivers		CRV-46246-A (RCA-AR-88F) as used in RDM	CRV-46246-B (RCA CR-88) as used in RDM-1 Manual NAVSHIPS 91061 Download 28.9 MB pdf
				1945 photo
		CRV-46246-A (RCA-AR-88F) as used in RDM		1945 photo







	Tone Keyer for RDM


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Crosby SSB Diversity Receiver	Info and Photos from NAVSHIPS 93224 - not known if a mil-spec version was fielded