PRD-1

Background
CY-949/PRD-1 & R-395 Receiver
CY-947/PRD-1 Battery Box
CY-950/PRD-1 Accessory Transit Case
CY-954/PRD-1 Receiver Transit Case
DY-79/PRD-1 Dynamotor
CX-2269U Power Cable
MT-1283/PRD-1 Jeep Mount (M38A1?)
Manual Illustration of PRD-1 on Jeep
Related Equipment for reference
Related Web Pages
Links

Background

The PRD-1 is an H.F. receiver designed for direction finding. It can be mounted on it's special tripod or using a special mount that allows leveling of the radio, on the fender of a jeep , like the M38A1. It was used in Vietnam and possibly the Korean conflict. SP4 James T. Davis was an american advisor in Vietnam helping the ARVN to use the PRD-1 and was the first American killed in Vietnam.

This is a tube type radio.

The PRD-1 did not work well against transmitters using Near Vertical Incidence Sky wave antennas. These "cloud Burner" antennas send the H.F. signal straight up and when it bounces back covers hundreds of miles from the transmitter location. Much better coverage than you could get with a 1/4 vertical whip antenna, but nowhere close to the range of a good horizontal dipole antenna or beam. The NVIS antenna is good for comms in a battle situation and provides better coverage than VHF radios. Since the sky wave is coming down at a steep angle the loop antenna on the PRD-1 does not give good results.

Overall Photo with Dynamotor power supply under R-395.

CY-949/PRD-1 & R-395 Receiver

R-395/PRD-1 Receiver

	Covers 100 Kc to 30 Mc. The CY-949 transit case is in the background to the right of the of the photo. When I was using this radio many years ago I could hear many broadcast stations. In many cases 2 or sometimes 3 stations could be separated on the same frequency by rotating the antenna.

	Front Panel while mounted on Dynamotor P.S.

CY-947/PRD-1 Battery Box

Holds a lot of batteries and the bottom mates to the tripod and the top mates to the bottom of the 395 receiver.
1 each type BA-404/U is connected to pins D & A supplying +1.5 V for filaments
4 each type BA-404/U are connected is series to pins B & A (and also to E & A) supplying -6 V.
2 each type BA-419/U are connected in parallel to pins C & A supplying +90 V (B+).

CY-950/PRD-1 Accessory Transit Case

MT-870 Tripod
Loop antenna
sense antenna
AN/PRD-1 Compass Adapter
32374 Open end & hex wrench
SM-B 133852 Tool
Spare Fuse from DY-79 front panel
"T" handle casting with small Allen wrench

CY-954/PRD-1 Receiver Transit Case

Holds the R-395 receiver

DY-79/PRD-1 Dynamotor

I have removed the spare fuse in order to bring out the 20 to 32 VDC power wires. The bottom mates to the tripod and the top mates to the bottom of the 395 receiver.

CX-2269U Power Cable

One connects to the DY-79 and the other end has 3 male pins that go the the M38A1? or outer power source.

MT-1283/PRD-1 Jeep Mount (M38A1?)

This mount has provision to level the receiver even when the jeep is on sloping ground.

Manual Illustration of PRD-1 on Jeep

Figure 25 from the manual showing the PRD-1 mounted on the jeep.

Transit Cases

ID	Nomenclature	Pounds	Size
CY-947	Battery Box	12 (empty)	16x14x5"
CY-950	Transit Case with loop antenna & tripod	71	42x16x10"
CY-954	Transit Case with DY-79/PRD-1 Dynamotor	105	22x20x22"
CY-949	Transit Case with R-395/PRD-1 Receiver	175	28x21x27h
MT-1283/PRD-1	Jeep Mount	70

Related Equipment for reference

AN/PRD-10 Manpack Radio DF Set [MPRDFS]

AN/PRD-11 Radio Receiver Direction Finder Set (NSN 5825-01-188-3435)

Called "MINI-FIX", see the FAS web page on AN/PRD-11, MINI-FIX

AS-3732 (20 - 175 MHz) or AS-3733 (20 - 850 MHz) Antenna
IP-1355 Panoramic Indicator - spectrum display
AN/GRR-8(V) Receiver, Tuners: TN-586 (0.5 - 30 MHz), TN-584 (20 - 250 MHz), TN-585 (250 - 500 MHz)
C-11495 Processor Display Control - digital and compass rose displays of bearing
Speaker Assembly
CV4090, up-converter

Manuals

TM 11-5825-278-12-1 (063258.pdf) = restricted
TM-11-5825-278-12-2 (ETM 058582.pdf)
TM 11-5825-278-12-3 (064718.pdf) = restricted
TM 11-5825-278-23P (061798.pdf) = restricted

AN/PRD-12, Lightweight Mantransportable Radio Direction Finder System (LMRDFS)

Manpacked 60 lbs Carried by 2 soldiers
Comm intercept/DF system; on emitter location missions, works with TEAMMATE; ideal in LT, Abn, ASSLT, SOF Ops,. Rapid relocation; optimizes collection in forward Area of Operations

FM 34-1 Intelligence and Electronic Warfare Operations- Chapter 2 - Fundamentals of IEW Operations -
How To Net an AN/TRQ-32a(V)2 With an AN/PRD-12 -

AN/TRQ-23

This is also a DF set.

AN/TRQ-32V Receiving set TEAMMATE

HMMWV
EA (jam): COMINT

AN/MLQ-38 Ground-Based Common Sensor Heavy & AN/MLQ-39 Ground-Based Common Sensor Light

Hvy: Electronic Fighting Vehicle (XM5), Lt: HMMWV
Intercept and DF: COMINT and/or ELINT EA(jam): COMINT Targeting location data Data downlink to CGS

USMC Mobile Electronic Warfare Support System (MEWSS)

Directional Finder (DF) System (AN/PRD-10)
Two Acquisition Receivers (WJ-8618B)

Intelligence and Electronic Warfare Common Sensor (IEWCS)

Section XI. EQUIPMENT -

AN/FSQ-144V (TROJAN)

is the Army's remote collection system supporting in-garrison collection by tactical MI units.

FM 24-33 Communications Techniques: Electronic Counter-Countermeasures. 17 July 1990.
FM 34-40 (S)Electronic Warfare Operations (U). 9 October 1987.
FM 34-40-7 Communications Jamming Handbook. 23 November 1992.
M 100-5 Operations. 19 June 1993.