DDR-5 Gallery

The DDR-5 family of receivers could be, and were, configured in a huge variety of ways.  To maintain some semblance of sanity while sorting through the photos of these receivers, I built the following tables.  With any luck, this may help you sort through the various options...  Among the many TMC documents was a fat binder evidently used by Ernie Matson (VP Sales) to help configure DDR-5 radios.  This included single-page drawings of some of the configurations, and I've included scans of the ones I have.  There are also a bunch of example system diagrams on large drawings.  I'll add them and a more thorough technical discussion of the remote-tuned Technimatic DDR-5's at some point.

Manually Tuned DDR-5's

DDR-5 Modules

To figure out which of the many version of this receiver you're dealing with, you first have to be able to recognize the components of the system.  I found the following table to be useful:

Module	Picture	Function
HFR		RF Tuner.  This unit is essentially a conventional front end with first mixer for a superhet radio.  It's local oscillator includes a varactor that allows it to be phase-locked to the synthesizer.  The unit also includes the first IF amplifier at 1.75Mc.  HFR-1 shown.
HFS		Synthesizer.  This unit is the synthesizer used to phase-lock the local oscillator to the operating frequency.  It has a numerical readout, but its digits are merely set by the frequency switches.  HFS-1 shown.
AFC		Automatic Frequency Control.  This unit operates within the 250Kc IF of the receiver and compensates for drift in the receiver front end, and in the distant transmitter.  AFC-2 shown.
HSP		Audio Switch Panel.
HFI		IF Amplifier.  Contains the 2nd mixer, 250 Kc IF amplifier, and set of bandpass filters.  HFI-1 shown.
HNF		Variable Notch Filter.  This filter sits in the 250Kc IF chain.  It up-converts to 447-460Kc, passes through a fixed notch filter, then down-converts to 250Kc again, using a pair of mixers and internal 197-213Kc oscillator.  HNF-1 shown.
HFA		Detector and Audio Amplifier.  Contains an AM detector, product detector, BFO, and audio output stages.  HFA-1 shown.
HAF		Audio Filter.  A passive LC dual-channel filter with independent hi- and lo-pass functions.  HAF-1 shown.
HFP		Power Supply.  Dual regulated supply that supplies most of the B+ and filament voltages for the receiver.  It also provides switched AC supply for certain functions.  HFP-1 shown.
HSS		Speaker Panel.  HSS-1's (one speaker) and HSS-2's (dual speakers) are used in various configurations.  Shown is an LSP-1, since I don't have a decent photo of an HSS--they're nearly identical.
DVM		Diversity Visual Monitor.  Visual tuning aid for diversity operation.
HPP		Power Panel.
MSA		Multiple Sideband Adapter.  This unit contains a common 3rd mixer that converts the 1.75Mc IF input down to 250Kc.  There are then four independent  IF's spaced symmetrically around 250Kc (2 below, 2 above), with independent AGC's and four independent sets of  product detectors, BFOs, squelch, and AF amplifiers.  This unit usually works with MCG.  MSA-1 shown.  The MSA/MCG pair essentially replaced the HFI & HFA of the earlier receivers.
MFP		Power Supply.  Supplies power to the MSA.  MFP-1 shown.
MCG		Multiple Carrier Generator.  Provides the 2Mc translation frequency for the 3rd mixer, and BFO injections at 243.71, 250.00, and 256.29 Kc for the MSA.  MCG-1 shown.
SBS		Multiple Sideband Adapter.  This unit contains an input mixer, a 250Kc IF with multiple filters, and two sets of AM and product detectors, and 2 audio outputs.
HFF		Radio Frequency Amplifier, Fixed Tuned.  This unit replaces the HFR in the various fixed-tuned receivers, providing 8 pre-set, fixed receive frequencies.

Overview

The chart below outlines the various configuration of manually tuned DDR-5's.  Many of these configurations had military designations; refer to the cross-reference chart to see which is which.

Type	Tuner	Synthesizer	AFC	IF/Audio	Spkrs	Pwr Supply	AC Pnl	Other	Dwg
DDR-5	HFR-1	HFS-1	AFC-3	HFI-1, HFA-1, HSP-1		HFP-1
DDR-5A	2xHFR-1	HFS-1	2xAFC-3	2xHFI-1, 2xHNF-1, 2xHFA-1, 2xHAF-1	2xHSS-1	2xHFP-1	HPP-1	DVM-4
DDR-5A1	2xHFR-1	HFS-1	2xAFC-3	2xHFI-1, 2xHNF-1, 2xHFA-1, 2xHAF-1, 1xHSP-2	1xHSS-1	1xHFP-1	HPP-1	DVM-4
DDR-5B	HFR-1	HFS-1	AFC-3	HFI-1, HNF-1, HFA-1, HAF-1, HSP-2	HSS-1	HFP-1	HPP-1
DDR-5B1	HFR-1	HFS-1	AFC-3	HFI-1, HNF-1, HFA-1,  HSP-2	HSS-1	HFP-1	HPP-1
DDR-5C	2xHFR-1	2xHFS-1	2xAFC-3	2xHFI-1, 2xHNF-1, 2xHFA-1, 2xHAF-1, 1xHSP-2	2xHSS-1	HFP-1	HPP-1
DDR-5CA	2xHFR-2	2xHFS-1	2xAFC-3	2xHFI-1, 2xHNF-1, 2xHFA-1, 2xHAF-1, 2xHSP-2	HSS-1	2xHFP-1	HPP-1
DDR-5D	Unknown
DDR-5E	2xHFR-1	2xHFS-1		2xSBS-2, 1xHSP-2	HSS-2	2xHFP-1	HPP-2	DVC-1
DDR-5G	2xHFR-1	2xHFS-1		2xMSA-1, MCG-1	HSS-2	HFP-1	HPP-2
DDR-5H	2xHFR-1A	HFS-1		2xMSA-1, MCG-1		HFP-1, MHPA-1
DDR-5J	2xHFF-1	HFS-1		2xMSA-1, MCG-1		HFP-1, MFP-1	HPP-1
DDR-5K	HFR-2	HFS-1	AFC-3	MSA-1, MCG-1	HSS-8	HFP-1, MFP-1	HPP-1
DDR-5KA	HFR-2	HFS-1	AFC-3	MSA-1, MCG-1	HSS-8	HFP-1, MFP-1
DDR-5KB	HFR-2B	HFS-2	AFC-3	MSA-1, MCG-1	HSS-8	HFP-1, MFP-1	HPP-1
DDR-5KS	HFR-2B	HFS-2		MSA-1, MCG-1	HSS-8	HFP-1, MFP-1	HPP-1	220v, 50cps operation
DDR-5KS1	HFR-2B	HFS-2		MSA-1, MCG-1	HSS-8	HFP-1, MFP-1	HPP-1	220v, 50cps operation
DDR-5KS1	HFR-2B	HFS-2		MSA-1, MCG-1	SPP-4004	HFP-1, MFP-1	HPP-1	220v, 50cps operation
DDR-5L	2xHFR-1A	HFSR-1	2xAFC-3	2xMSA-1, 2xMCG-1, 2xHFA-1	BSP-6P	2xHFP-1	HPP-1
DDR-5LS	2xHFR-2B	HFS-2		2xMSA-1, 2xMCG-1	BSP-6	2xHFP-1	HPP-1	like 5L, 220V, 50cps op
DDR-5M	2xHFR-2	2xHFS-1	2xAFC-3	2xMSA-1, 2xMCG-1	2xHSS-6	2xHFP-1
DDR-5P	2xHFR-2	HFS-1	2xAFC-3	2xMSA-1, 2xMCG-1, 2xHFP-1	HSS-4
DDR-5Q	HFR-2	HFS-1		MSA-1	HSS-5	HFP-1
DDR-5R	HFR-2	HFS-1		MSA-1, MCG-1	HSS-4	HFP-1		CFA-1
DDR-5S	HFR-2, HFF	HFS-1		HFA, RMXI-2		HFP-1
DDR-5T	HFR-2, HFF	HFS-1		HFA, RMXI-2		HFP-1
DDR-5U	HFR-1A	HFS-1		HFI-1, HFA-1, RMXI-2	HSS-1	HFP-1		CFA-2
DDR-5V	HFR-1A	HFS-1	AFC-3	MSA-1, MCG-1		HFP-1		CFA-1
DDR-5Y	2xHFR-2	HFS-1		2xHFI-1, 2xHFA-1	2xBSP-4	HFP-1	HPP-1	2 special filter panels
DDR-50	2xHFR-1	HFS-1	2xAFC-3	2xMSA-1, 2xMCG-1, HSP-2	HSS-2	2xHFP-1	HPP-2
DDR-51	2xHFR-1	HFS-1	2xAFC-3	2xMSA-1, 2xMCG-1	HSS-2	2xHFP-1	HPP-2
DDR-52	HFR-1	HFS-1	AFC-3	MSA-1, MCG-1, HSP-1	HSS-2	HFP-1	HPP-1
DDR-53	2xHFR-1	2xHFS-1	2xAFC-3	2xMSA-1, 2xMCG-1, 2xHSP-1	2xHSS-2	2xHFP-1	2xHPP-1
DDR-54	2xHFR-1	2xHFS-1	2xAFC-3	2xMSA-1, 2xMCG-1, 2xHSP-1	2xBSP-2	2xHFP-1
DDR-55	2xHFR-2	HFS-1	2xAFC-3	2xMSA-1, 2xMCG-1, 1xHFP-1,	HSS-4	HFP-1, MHPA-1
DDR-501	HFF-1	HFS-1	AFC-3	MSA-1, MCG-1, HSP-1	HSS-2	HFP-1
DDR-502	2xHFF-1	2xHFS-1	2xAFC-3	2xMSA-1, 2xMCG-1, 2xHSP-1	2xHSS-2	2xHFP-1
DDR-503	2xHFF-1	HSF-1	2xAFC-3	2xHFI-1, 2xHNF-1, 2xHFA-1, 2xHAF-1	2xHSS-1	2xHFP-1	HPP-1	DVM-4
DDR-505	HFR-1A	HFS-1A	AFC-3	HFI-1, HFA-1, HAF-1,  HNF-1, RMX-2	BSP-2X	HFP-1	HPP-1
DDR-551	HFR-1	HFS-1		SBS-1	HSS	HFP-1	HPP-1
DDR-551A	HFR-1	HFS-1	AFC-3	SBS-1	HSS	HFP-1	HPP-1

DDR-5

There appears to have been an early version of the DDR-5 receivers called just "DDR-5".  Note the different appearance of the HFR and HFS units in some of the photos.  Indirect evidence from comparing various photos suggest that these two models were just renamed DDR-5A (dual) and DDR-5B (single).

	621.26-2  This appears to be the earliest version of the DDR-5 for which there is a photo. Note that the HFR was quite different in later versions.	no info on photo	625.12-2

DDR-5A

This is the original dual-diversity version of the receiver.  It has only one HFS Synthesizer, so both halves of the receiver must be tuned to the same frequency, when the synthesizer is in use, so this is a "spatial diversity" receiver.

Un-numbered color photo of DDR-5A	Also un-numbered, this photo may be of an early version of the "A"; note the metal rings around the HFR's left dial, the absence of the HPP-1 power panel at the bottom of the left rack, and the 2-speaker panel in place of an HSS-1	625.12-7  Rear of DDR-5A rack.	625.12-1 Another shot of the early 'A', with bottom doors closed.
625.12-2.  Yet another shot of the earl 'A'.	625.12-6  Early 'A' rear view with doors shut.

DDR-5B

The "B" model is the single-rack, non-diversity, version of the "A".

629.14-2  DDR-5B	6310.11-2  DDR-5 Rack, front	626.27-4  DDR-5B Rack, rear.	Special tools for DDR-5.

DDR-5C

This version of the receiver is a full frequency/spatial diversity configuration with two independent synthesizers.  Where the "A" version has only a single HFS to lock both of its HFR's to the same frequency, the "C' radio has two synthesizers.. essentially two independent synthesized receivers.

637.9-1  DDR-5C front.	637.9-3  DDR-5C with HFI swung out.	637.9-2  DDR-5 overall view.

DDR-5H

This version is a single-rack diversity receiver with 2 sets of 4 independent sidebands (MSA's).

Configuration		643-25-1
HFR-1A RF Tuner
HFR-1A RF Tuner
HFS-1 Synthesizer
MSA-1 Multiple Sideband Adapter
MSA-1 Multiple Sideband Adapter
MCG-1 Mux Carrier Generator
HFP-1 Power Supply
MHPA-1 Dual Power Supply

DDR-5K (AN/FRR-74)

This version is a single-rack non-diversity rig, configured to receive 4 independent sidebands.

6511.11-5  DDR-5KC front	657.8-3  DDR-5K overall view.	657.8-4  Rear view of DDR-5K rack.
6511.11-5  DDR-5KA front view.	6511.11-6  DDR-5KA oblique view.	6511.11-7  DDR-5KA rear view.

DDR-5L

The '5L is the diversity version of the 5K.  It can receive two sets of 4 independent sidebands, or using the common synthesizer, one set of 4 independent sidebands in spatial diversity.

Scan of manual page for DDR-5L.	655.24-3  Close-up of cabling.	655.26-7  AX-390 in DDR-5L Blower.

DDR-5 Special

This receiver was one of probably many "special" configurations.  This particular one has only an HFR, HFS, HFI, and HFP.  The detector must have been customer supplied, and there was no AFC.

Photo 644.6-6

DDR-50

The DDR-50 is a single-rack spatial diversity receiver with 2 HFR's locked to a single HFS.  IF amplifiers, filters, detectors, and audio amps are implemented in this radio with SBS's.

Configuration	D648.14-2
HFR-1 RF Tuner
HFS-1 Synthesizer
HFR-1 RF Tuner
HSP-2 Audio Switch Panel
AFC-2 AFC Cntl Unit
SBS-1 Sideband Adapter
AFC-2 AFC Cntl Unit
SBS-1 Sideband Adapter
HFP-1 Power Supply
HSS-2 (?) Speaker
HPP-1 Power Panel

DDR-51

The DDR-51, like the '50, is a spatial diversity receiver that also uses a pair of HFR's with AFC's, sharing a single synthesizer.  In this receiver, however, MSA's and MCG's are used as IF and audio components.

Configuration	D648.14-1
HFP-1 Power Supply
HFP-1 Power Supply
HFR-1 RF Tuner
HFS-1 Synthesizer
HFR-1 RF Tuner
AFC-2 AFC Cntl Unit
MSA Multiple Sideband Adapter
AFC-2 AFC Cntl Unit
MSA Multiple Sideband Adapter
MCG Mux Carrier Generator
MCG Mux Carrier Generator
HPP-1 Power Panel

DDR-52

This version is a non-diversity reciver using an MSA/MCG IF/Detector assembly.

Configuration	642.8-16
HFR-1 RF Tuner
HFS-1 Synthesizer
MSA-1 Multiple Sideband Adapter
AFC-3 AFC Cntl Unit
MCG-1 Mux Carrier Generator
HSP Audio Switch Panel
HFP-1 Power Supply
HSS-2 (?) Speaker
HPP-1 Power Panel

DDR-55

This version appears to be a dual-diversity configuration in a single cabinet.  I don't have photos of the '55.

DDR-501

In this receiver, the manually tuneable HFR is replaced with an HFF, an RF unit that provides 8 preset, fixed-tuned receive frequencies.  The -501 receives 4 independent sidebands in a non-diversity configuration.

Configuration	642.8-14
HFF Fixed-tuned RF Unit
HFS Synthesizer
MSA-1 Multiple Sideband Adapter
AFC AFC Control Unit
MSG-1 Mux Carrier Generator
HSP Audio Switch Panel
HFP-1 Power Supply
HSS-2 (?) Speaker
HPP-1 Power Panel

DDR-551

The DDR-551 is a non-diversity configuration that uses an SBS dual-channel IF/detector.

643.13-2	648.19-2	648.19-1	543.13-3

DDR-5 Mystery Radios

In the photo stash there are several photos of DDR-5's that I cannot match up with any known configurations.  

This version appears to be a single-rack diversity receiver, without a synthesizer.  It has two complete receivers, each consisting of an HFR, an AFC freq control, and an SBS multiple sideband adapter.  There must be a power supply, or two, but they must be mounted in the rear of the rack.	642.8-11
Configuration
HFR RF Tuner
SBS-1 Multiple Sideband Adapter
AFC Automatic Freq Control
HFR RF Tuner
SBS-1 Multiple Sideband Adapter
AFC Automatic Freq Control
HSP Audio Switch Panel
HSS-8(?) Dual Speaker Panel
HPP-1 Power Panel

Like the above mystery radio, this one appears to be a diversity set with no synthesizer, but is uses the MSA/MCG multiple sideband adpaters instead of the SBS.	642.8-8
Configuration
HFR RF Tuner
MSA Multiple Sideband Adapter
AFC Automatic Freq Control
MCG Multipler Carrier Generator
HFR RF Tuner
MSA Multiple Sideband Adapter
AFC Automatic Freq Control
MCG Multipler Carrier Generator
HFP Power Supply
HPP Power Panel

This radio is very similar to the DDR-5B, but seems to have a different audio switch panel.  Examination of the photo shows that the tags have military designations.
Configuration
HFR RF Tuner
HFS Synthesizer
AFC Automatic Frequency Control
(?) Audio Switch Panel, but not HSP
HFI IF Amp
HFA-1 Detector and Audio Amp
HAF-1 Audio Filter
HFP-1 Power Supply
HSS-? Speaker Panel
HPP-1 Power Panel

This configuration is similar to the DDR-5K, but.. not quite the same.  It has no MFP power supply.
Configuration
HFR RF Tuner
HFS Synthesizer
MSA Multiple Sideband Adapter
AFC Automatic Freq Control
MCG Multiple Carrier Generator
HAF Audio Filter
HFP Power Supply
HSS-8(?) Speaker Panel
HPP Power Panel

This radio is very similar to the DDR-5M.  It's a diversity set with 2 tuners, 2 synthesizers, and 2 MSA/MCG sets.  It differs from the -5M in its speakers, and in having a pair of HAF's installed as well		642.8-2
Configuration
HFR RF Tuner	HFR RF Tuner
HFS Synthesizer	HFS Synthesizer
MSA Multiple Sideband Adapter	MSA Multiple Sideband Adapter
MCG Multiple Carrier Generator	MCG Multiple Carrier Generator
HAF Audio Filter	HAF Audio Filter
HFP Power Supply	HFP Power Supply
LSP-7 Dual Speaker	LSP-7 Dual Speaker
HPP Power Panel

This configuration is similar to both the DDR-5L and DDR-5P with some detailed differences.  It appears to be a dual-diversity radio with MSA/MCG IF/Detector Systems.		6512.9-8 (Dec 22, 1966)
Configuration
HFR RF Tuner	HFR RF Tuner
HFS Synthesizer	HFS Synthesizer
AFC Automatic Freq Control	AFC Automatic Freq Control
MSA Multiple Sideband Adapter	MSA Multiple Sideband Adapter
MCG Multiple Carrier Generator	MCG Multiple Carrier Generator
HFP Power Supply	HSS-? Dual Speaker
HFP Power Supply	HFP Power Supply

This version is a "miniature" single-rack receiver.  No markings or info on the photo
Configuration
HFR RF Tuner
HFS Synthesizer
SBS-1 Multiple Sideband Adapter
HFP Power Supply
HSS-8(?) Dual Speaker Panel

Remotely Tuned DDR-5's

In the mid-sixties the Navy and other agencies (notably NASA) developed requirements for remotely tuned equipment, which lead to TMC's development of the so-called Technimatic equipment.  The DDR-5's were among the first TMC systems to be provided with remote controls.  Early nomenclature wasn't absolutely consistent, so for example, there is a DDR-5BR (remote version of the DDR-5B), but later the remotely tuned radios started to be listed as DDRR-5x.

The HFR, HFS, HFA, HFI units of DDR-5 spawned new remotely-tuned versions HFRR, HFSR, HFAR, HFIR, and so forth.  Their appearance from the front panel is identical to their manually-tuned versions.  Viewed from the rear, however, rows of Ledex rotation actuators is a tip-off that you're looking at an "xxxR" unit.  In addition to the "R" versions, some of the DDR-5 modules morphed into "A" versions, for example the MSAA, MCGA and so forth, presumably for "Automatic".

The remote control systems used the following additional units to handle data reception, decoding, and storage:

Module	Picture	Function
RTTD		Data decoder/receiver.  This unit received data from the remote controller via a teletype land line, decoded the commands, and stored them into the RTMU.  RTTD-1 shown.
RTMU		Signal Data Converter-Storer. This unit received digital commands from the RTTD, stored the commands in a digital memory, performed decoding functions, and drove the various xxxR units in the receiver.  RTMU-1 shown.
LRCB		Control Terminator, used in the DDRR-506.  This photos is actually of an LRCD-1, but the LRCB is identical in appearance.

The operator end of the remote tuning systems included the ARCx units.

ARCA Automatic Receiver Remote Control System, Tape

R6412.2-8.  Photo of Ray deP with an unknown associate at the controls of an ARCA-1 receiver Technimatic remote control system.  This ARCA-1 has 1 RTPA-1 Electronic Programmer, 3 RTIA-1 Channel Indicators, and an RTKY-1 Paper Tape Reader/Punch.	667.13-3.  This photo is actually an RTPH, but the RTPA-1 that is used in the ARCA-1 is almost identical in appearance.	654.2-3.  The bottom unit in this photo is an RTIA-1.	No number.  RTKY-1 Paper tape reader/punch.

Overview

The following chart lists the various remote-controlled DDR-5 configurations.

Type	Tuner	Synthesizer	AFC	IF/Audio/Filter	Spkr	Pwr Sup	AC Pwr Panel	Remote Cntl	Other	Dwg
DDR-5BR	HFRR-2	HFSR-1	AFCR-3	HFIA-1, HFAR-1A, HAFR-1	HSS-3	HFP-1		RTMU-1, RTTD-1	RGCB-1, AK-101
DDR-5BR1	HFRR-2B	HFS-1	AFCR-3	HFIA-1, HFAR-1A, HAF-1	HSS-3	HFP-1		RTMU-2, RTTD-1	RGCB-1, AK-101
DDR-5N	2xHFR-2	HFS-1		2xMSA-1, 1xMCG-1, 2xHFP-1, 1xHSP-2	2xBSP-2	2xHFP-1		RTMU-1, RTTD-1	4xDVC-1
DDR-504	HFRR	HFSR		HFIR, HFAR, HAFR, HFP	HSS	PSP-1		RTMU-1, RTTD-1	CFA-1
DDR-506	8xHFRR-3	8xHFSR-1	8xAFCR-3	8xMSAA-1, 8xMCGA-1		12xHFP-1		8xLRCB-1	FACA-1 (?)
DDR-552	HFRR-2	HFSR-1	AFC-3	HFIR, HNF, HFAR, HAF		HFP-1		RTMU-1, RTTK-1, RTPP
DDRR-5B	HFRR-2	HFSR-1	AFC-3	HFIR-1, HNF-1, HFAR-1, HAF-1	HSS-3	HFP-1		RTMU-1, RTTD-1
DDRR-5B1	HFRR-2	HFSR-1	AFC-3	HFIR-1, HFN-1, HFA-1, HAFR-1, HSP-2	HSS-6	HFP-1		RTMU-1, RTTD-1
DDRR-5C	2xHFRR-2	2xHFSR-1	2xAFC-3	2xHFIR-1, 2xHNF-1, 2xHFAR-1, 2xHAF-1	2xHSS-3	2xHFP-1		2xRTMU-1, 2xRTTD-1
DDRR-5K	HFRR-2	HFSR-1	AFC-3	MSA-1, MCG-1	1x(?)	HFP-1		RTMU-1, RTTD-1
DDRR-5L	2xHFRR-2	HFSR-1	2xAFC-3	2xMSA-1, 2xMCG-1	1x(?)	2xHFP-1		RTMU-1, RTTD-1	RSTA-1 (?)
DDRR-5M	2xHFRR-2	2xHFSR-1	2xAFC-3	2xMSA-1, 2xMCG-1	BSP-6B	2xHFP-1		2xRTMU-1, 2xRTTD-1
DDRR-5N	2xHFRR-2	HFSR-1		2xMSA-1, 1xMCG-1, 1xHSP-2	2xBSP-2	2xHFP-1		RTMU-1, RTTD-1	4xDVC-1
DDRR-5P	2xHFRR-2	2xHFSR-1	2xAFC-3	2xMSA-1, 2xMCG-1	1x(?)	2xHFP-1		RTMU-1, RTTD-1
DDRR-5Q	HFRR-2	HFSR-1		MSA-1	HSSR-5	HFP-1		RTMU-1, RTTD-1
DDRR-5R	HFRR-2	HFSR-1		MSA-1, MCGR-1	HSS-4	HFP-1		RTMU-1, RTTD-1	CFA-1
DDRR-5S	HFRR-2	HFSR-1		SBS-1, RMXI-2	HSS-4	HFP-1		RTMU-1, RTTD-1	CFA-1
DDRR-5T	HFRR-2	HFSR-1		HFI-1, HFA-1, RMXI-2		HFP-1		RTMU-1, RTTD-1
DDRR-5W	HFRR-( )	HFSR-1	AFC-3	HFIR-2, HFA-1		HFP-1	HPP-1	RTMU-3, RTTD-3

DDRR-5B

This version is the remotely tuned version of the single-rack, non-diversity DDR-5B.  This receiver appears to have been configured in several alternate ways, including the DDRR-5B1.  There were early versions of this receiver, again with slightly different configurations, designated the DDR-5BR and DDR-5BR1..

646.10-3.  DDRR-5B described on back of photo as "incomplete".  There appears to be no RTMU at the bottom.	6411.2-3  DDRR-5B with rack door closed.	6411.2-1  DDRR-5B with rack doors open.	652.18-11.  DDRR-5B rear view.
652.18-11.  DDRR-5B from left rear.	DDRR-5B1 front view.	DDRR-5B1 with ARCD-1 remote controller.	662.18-7.  DDR-5BR1 front view.
DDRR-5B1 shown on the production line, with an ARCD-1 at the right, and a DDR-10 of some flavor on the left.	DDR-5BR1 annotated photo.	662.18-10.  DDR-5BR1 rear view.	DDR-5BR overall view.

DDRR-506

This monster (referred to sometimes as the DDR-506) was built for NASA and deployed on the tracking ships used for the Apollo program.  The radios were a backup system to be used in case the satellite-based data link failed.  Evidently the satellite system failed during at least one of the moon missions, and this receiver was used to receive, download, and then uplink the lunar injection burn data for the spacecraft.  Quite an accomplishment for an HF link!

The radio consists of 8 separate receivers, all remotely controllable.  The NASA receivers, and their parts, are easily identifiable, as they are painted a bilious green color, rather than the usual "TMC gray".

Color shot showing the front panel of the 5-rack DDRR-506 (also sometimes referred to as the DDR-506).	Closeup of the '506 showing mainly the center rack with its array of 8 MSAA-1's.	Annotated photo of the '506.	Front view of the '506.
Operator's console for the DDR(R)-506, consisting mainly of 8 LRCC-1's.	Color shot of the LRCC-1's.