PRC-112 Survival Radio
© Brooke Clarke 2010 - 2020
Background
AN/AYD-1 Personnel Locator System (PLS)
PRC-112
Opening
Versions
Combat Survivor Evader Locator
(CSEL) PRQ-7
KY-913 Program Loader
Interrogators
Battery
Battery Adapter
NSNs
Manuals
Patents
Related
Links
Background
The PRC-112() Survival Radio
replaces the
PRC-90 family of survival
radios that are issued to military aircraft crew members.
The problem with the old survival radios was that they were simple
beacon transmitters with no ID capability so when one went off
accidentally (a common occurrence considering that there are
roughly 556,000 121.5 MHz beacons and 429,000 406 MHz
beacons) there was not an easy way to tell if the signal was real
or not making for a lot of wasted effort. Satellite
monitoring of the old analog survival beacons was shut down on 1
Feb 2009.
The new 406 MHz survival beacons each have a serial number and
other identification information built in. A rough position
can be determined just from the 406 Mhz carrier and the motion of
the satellite that's receiving it. A much better position
can be obtained if the beacon transmitter includes a GPS
receiver. As of 2009 there were about three quarters of a
million 406 MHz beacons operational.
In the movie "Behind Enemy Lines" this is the radio used by Owen
Wilson throughout most of the story. It even makes static
noises after the tank attacks a building in Hoc with the battery
removed.
AN/AYD-1 Personnel Locator System (PLS)
The AYD-1 is the complete system
consisting of:
- SARSAT (Search And Rescue SATelitte) System
- The KY-913/PRC-112 program loader loads the survival radio
- PRC-112() with frequency of Programmable operation (225 to
300 MHz) and a personal ID number (actually the SARSAT data
set) on 406.028 MHz.
- The AN/ARS-6(V) is the aircraft interrogator system that
interoperates with the PRC-112 giving the pilot either bearing
or bearing and distance to the survivor.
- TS-4360 Test Set
PRC-112 Aircrew Member Survival Radio
PRC-112
 |
243 Beacon
243 coms
Custom freq B
Custom freq A
282.8 coms
121.5 coms
121.5 Beacon
|
1985
The PRC-112 is a step up from the PRC-90 in that it has more
channels (two of them can be programmed) and Distance Measuring
Equipment (wiki:
DME)
built in. When a search aircraft gets within line of sight
of the PRC-112 it can send a burst transmission on any of the non
beacon channels and if the PRC-112 is not transmitting it will
respond to the aircraft. Note the aircraft needs to know the
ID# (000000 to 999999) of the radio. While doing so a light
on the PRC-112 will be on for about eight seconds telling the
survivor that someone is getting his range and bearing.
This version does not have GPS and does not support SARSAT 406 MHz
digital data.
The TS-4317 Communications analyzer supports the DME mode of the
PRC-112.
Aproximatley 25,000 made.
There are 9 variations on the basic PRC-112.
Fig 8
PRC-112 Open

|
Fig 9
PRC-112 Inside Modules

|
In
Fig 9 above showing the modules inside the
PRC-112 you can see a distorted module to the left of the TADIRAN
Transponder. The module at the right top (next to the
Transponder) is a 72 MHz TCXO. The module at the front
marked D793 has a coax that leads to the antenna. The right
hand red wire at the very upper right (in the narrow part of the
chassis) is connected to the battery socket negative battery
terminal. There's 10 Ohms resistance between the two red
wires when the power is on or off.. The metal can with the
two red wires may be a filter in the negative DC power line.
Opening (probably the same for all versions)
The cover is held on by what may be
Bristol
Key Chart head metric 2.2-0.45x9 mm screws. A 0.050" hex
wrench will fit into the hole, but when turned tends to strip
leaving a round hole.
Kroil
penetrating oil is also a helpful thing to have on hand.
Some of the screws may have been epoxied to prevent their removal
(maybe also the reason for using Bristol heads). More when
the wrenches arrive.
The L-key wrenches arrived are are the wrong set. This set
marked "Bristol Wrench" & "Spline Key Kit" contains 10 keys
and is sold on eBay as "
SS-408 - Bristol
Spline Wrenches Collins & Bell Howell". It contains:
-060, -069, -072, -076, -096, -111, -133, -145, -168, & -183
spline L-keys. All of them too large.

The "SS-508 Spline Key Kit" is the one needed for the
PRC-112 cover screws and has 9 L-keys. Max-Gain
Systems
sells
them on line for ham radio and electronics.
After picking out the epoxy on a few screws and using Kroil for
many days there were screws that just would not budge with
reasonable force. Using a 500 Watt soldering iron on the
screw head did not help. What worked was drilling out the
screws.
Once the cover is removed to free up the module assembly the four
corner screws on the printed circuit board can be
removed. Leave the four screws in the center of the
PCB since these hold modules. The top (closest to the cover)
internal PTT screw needs to be removed since it also goes into the
module assembly.
PRC-112A(C)
Adds type 1 Voice encryption. (
Wiki)
PRC-112B GPS-112 Hook-112
This is the basic PRC-112 with the
Motorola GPS applique and Hook waveform.
Works with the Quickdraw 2 interrogator, Rockwell
RSC-125G, Cubic ARS-6 Ver12.
The PRC-112B (and later versions) probably looks like the
PRC-112G, i.e. with the LCD screen and input buttons for 2-way
text messaging.
PRC-112B1
adds GPS,
2-way messaging and encryption to the PRC-112C in a new
applique.
Works with the Quickdraw 2 interrogator, Rockwell
RSC-125G, Cubic ARS-6 Ver12.
PRC-112C
Made by Motorola this is just the
basic PRC-112 radio without GPS and without SARSAT data.
It has the improved sensitivityhe and knob upgrades (GD p/n
01-P21261J004).
The June 27, 2003 GD contract
adds GPS,
2-way messaging and encryption to the PRC-112C to make a
PRC-112B1
Connectors
In Fig 3 above of the battery connector you
can see that there are five electrical contacts surrounding
the two battery terminals. Two of these are for the
programmer interface. In Fig 4 above
of the top of the KY-913 programmer you can see the two
programming pins surrounding the two battery terminals. Note
in Fig 6 above that the KY-913
battery connector has the same five terminal arrangement
surrounding it's battery terminals. This must for
testing and flashing the memory of the programmer. There
is an adapte cable made by Aeroflex that interfaces their
communications tester to the radio battery connector and has
the 5 interface pins in addition to the two battery terminals.
There might be an antenna adapter that can be installed by
removing the tape antenna and screwing it onto the radio so
that a D&M type satcom antenna can be fitted.
The antenna is held to the radio with what looks like a 5/16-24
bolt.
There appears to be a coax connection possible but it would
require a special adapter with 5/16-24 threads and a center
conductor.
PRC-112D
Made by Engineering and
Professional Services (EPS). Finished their 1,000th
PRC-112D on March 24, 2006. Made by upgrading the modules
in the PRC-112. Adds Built In TEst (BITE) and battery life
indicators. EPS worked with Tadiran Spectralink on the
PRC-112D. They also developed a Helium leak test for the
PRC-112C because some radios got seawater inside.
PRC-112E
Feb 01, 2003 Made by Tadiran
Spectralink Ltd. See the PRC-112D above.
PRC-112F
Might not have been made?
PRC-112G Hook2 CSAR
Made by General Dynamics and
includes GPS, UHF satcom digital 2-way messenging &
encryption. Uses Software Defined Radio (SDR) technology.
Works with the Quickdraw 2 interrogator, Rockwell
RSC-125G, Cubic ARS-6 Ver12.
Optional SARSAT digital mode on 406.028 MHz
Has LCD screen and a number of buttons to interface with the
screen.
June 16, 1993 Motorola,
Inc., GEG, Scotsdale, Ariz., $8.3 million new work
modification to a firm fixed-price contract for the
production of a basic quantity of 611 AN/PRC-112 Survival
Radio Sets, an option quantity of 1,1583 AN/PRC-112
Survival Radio Sets and an associated data item. These
radio sets are necessary to achieve first-pass rescue
capability for downed crewman, minimizing the loss of
survivors to the elements or the enemy.
Maybe the kit shown at the top of this page.
|
APRIL 20, 2000 AN/PRC-112C
SURVIVAL RADIO SETS SOL DAAB07-00-R-B035 DUE 051200 POC
Cindy Cook, Contract Specialist (732)532-5415, Vernay
Salas, Contracting Officer (732)532-1257 WEB: CECOM
Acquisition Center's Business Opportunties page, http://acbop.monmouth.army.mil.
E-MAIL: salasv@mail1.monmouth.army.mil,
cookc@mail1.monmouth.army.mil.
This acquisition is being issued as A Sole Source to
Motorola, Scottsdale, AZ. This is to acquire 635 each
AN/PRC-112C Survival Radio Sets. |
Sep 28, 2001 Motorola sells
it's Integrated Information Systems division to GD.
|
June 27, 2003 General
Dynamics
Decision Systems, Inc., Scottsdale, Ariz., is being
awarded a $6,354,315 firm-fixed-price contract to
provide for assembly applique added to the AN/PRC-112 or
AN/PRC-112C radio to make an AN/PRC-112B1 (Global
Positioning System (GPS) capability) radio. This
applique adds GPS, 2-way messaging and encryption to an
AN/PRC-112 Multi-Mission Transceiver. Price includes
installation on 1,167 customer-furnished AN/PRC-112s at
$5,445 per kit. Total funds have been obligated. This
work will be complete September 2003. The 16th Special
Operations Wing, Hurlburt Field, Fla., is the
contracting activity (08620-03-F-0154). |
Dec. 5, 2000
Motorola (NYSE:MOT) Tuesday introduced its Combat
Search and Rescue (CSAR), GPS-112 Personnel Location
System.
This technology will combine beacon, radio,
transponder, GPS and two-way messaging capabilities into
a hand-held radio and interrogator system
Motorola's GPS-112 transceiver sends encrypted global
positioning data and two-way messages to provide
essential, quick and accurate location and rescue
information to aid in finding the grounded soldiers'
location.
Motorola's Quickdraw Interrogator can quickly plug into
the intercom system of virtually any aircraft,
transforming it into a CSAR platform. The information is
communicated in a single, short burst to the GPS-112
hand-held radio.
This technology provides rescue crews with a very
accurate, Low Probability of Interception/Low
Probability of Detection (LPI/LPD) system enabling them
to locate missing crewmember(s).
"The GPS-112 Personnel Location System combines the
field-proven benefits of the Motorola CSAR radio with
the convenient hand-held Quickdraw Interrogator to
provide our customers with a high level of accuracy,"
said Gary Johnson director of radio products business
unit of the Motorola Information Security Systems and
Products Division.
"Military and government personnel, around the world
will have a new, powerful, secure option with Motorola's
Personnel Location System."
|
Hook 112 adds civilian GPS to the basic PRC-112 as an applique
done by Motorola.
Combat Survivor
Evader Locator (CSEL) PRQ-7
The CSEL has replaced the PRC-112.
The Combat Survivor Evader Locator
(CSEL) (FAS:
CSEL,
Boeing,
)
integrates the GPS into the radio and supports the digital SARSAT
data.

Photo from
Boeing
- March 5, 1996
The Air Force has awarded Rockwell a $13
million contract for a worldwide
communications system that would be used to search
for downed pilots in combat environments, the
company said yesterday.
The Combat Survivor Evader Locator (CSEL) is a
lightweight, low-power, over-the-horizon radio
using an integrated Global Positioning System
receiver. The radio would be used in environments
like the one Air Force F-15 pilot Capt. Scott
O'Grady found himself in when he was shot down
over Bosnia last year. It took rescuers about a
week to find him.
|
The FY '98 DoD Director
of Operational Test and Evaluation (DOT&E) report
says that Boeing's [BA] Combat Survivor Evader Locator
(CSEL) system, which guides rescue units to downed
pilots, is not acceptable for combat use. "The CSEL
configuration tested is not effective and not suitable,"
the report says. CSEL is intended to replace the PRC-90
and PRC-112 survival radios now used by aviators of all
four services, providing a satellite communication link
and real-time position data. |
1999
FT. BELVOIR, Va.-The Air Force and Boeing [BA]
recently said that the Combat Survivor Evader Locator
(CSEL) program has demonstrated significant
improvements in the past year after the Pentagon ruled
it was not acceptable for combat use.
The CSEL's performance showed significant improvement
when compared to the testing results from the
engineering and manufacturing development phase, Air
Force Lt. Col. Norman Albert, CSEL program manager, told
sister publication Defense Daily at a briefing |
J-6431/PRQ-7 Adapter, Radio Set (NSN: 5820-01-500-0556) -
Cloning kit
CSEL Planning Computer Software
BB-2001A/U AN/PRQ-7 Rechargeable Battery Pack (
NSN:
6140-01-534-3856)
BA-5301/U AN/PRQ-7 Non-rechargeable Battery Pack (NSN:
6135-01-512-8740) The non-rechargeable battery pack
provides 2.8 Amp-hours of power and weighs only 8.4 ounces. The
pack contains a memory device that communicates its remaining
capacity to the CSEL HHR. DOT approved for commercial ground/air
transportation.
J-6769/U AN/PRQ-7 SPC Adapter, PN:
BTA-70581-2, (NSN: 5980-01-526-8017) Used with the PP-8498 SPC to
charge two CSEL Rechargeable battery packs. Backward compatible to
the earliest CSEL battery packs. Four (4) are required to populate
all stations in PP-8498 SPC.
Radio Set Adapter (RSA Nano), PN: 4866118-101 Installs between the
battery and HHR for mission parameter upload and download. Used to
load SAASM GPS Crypto Keys. Includes Serial/Crypto Fill Y-Cable,
quick-guide and canvas pouch.
CSEL HHR XX90 Adapter, PN: 4866118-102, Ba-5590 family to PRC-112
battery adapter
Replacement Parts
Descriptiopn
|
p/n
|
NSN
|
CSEL HHR Blade
Antenna (Replacement Kit) |
4866112-103-001 |
5985-01-502-7930 |
Earphone |
CEP601-CO3S |
5995-01-502-9465 |
Earphone Ear Tips
(Assorted Sizes) |
CEP300-EMXT |
5965-01-504-1051 |
Strap/Pouch
|
4866110-421-001, 721-00451
|
5935-01-458-9450 |
KY-913 Program Loader
Interrogators
These are the devices that find the
survival radio. Most are mounted in aircraft either as
avionics or as an add on to the intercommunication system.
There are also suitcase interrogators and hand held units.
The hand held unit plugs into the aircraft intercommunications
system (i.e. Quickdraw). The suitcase unit may contain a
LST-5 UHF Satcom radio and so could be operated anywhere.
The GD Satcom base station uses the PRC-112G (or maybe a special
version with external antenna connector and laptop interface to
send and receive encrypted digital messages.
Battery
Model
|
BA-5112/U |
NSN
|
NSN 6135-01-235-4168 |
Chemistry
(Primary)
|
LiSO2 |
Output: |
11.8
Volts
|
Capacity
|
2000 mAh |
Length: |
3.06 inches |
Width: |
2.25
inches |
Thickness: |
1.54 inches |
Battery Adapter
Takes 8each Energizer LS91 AA cells, i.e. a "12 Volt" adapter
marked for use only on the PRC-112D.
Fig 1

|
Adapter, Battery
12/6/2013
NSN: 9540-01-504-8134
|
Fig 2
 |
Use only 8 each Energizer 1.5 Volt LIthium
6135-01-333-6101.
Do not charge, short circuit, incarcerate or mutilate this
battery otherwise battery may vent or rupture releasing
toxic materials.
Warning: Do not use rechargeable batteries.
|
Fig 3
 |
Battery Adapter
5940-01-504-8134
Use only on AN/PRC-112D Survival Radio
Warning: Do not use rechargeable battteries in this
adapter.
|
Fig 4
 |
To Open:
1. Remove locking "U" shape clip.
2. Squeeze notched fingers together and push them down to
release end plate.
The convention that battery negative is the spring and the
fixed contact is positive is NOT true for this adapter.
You MUST follow the polarity guide! This may become
a problem if the stick on guide is not noticed.
Black printing against Olive drab is very hard to see let
alone read.
|
Fig 5
 |
The battery adapter is thicker, it protrudes at the front
and back of the radio.
It's also wider and protrudes to the right. But not at all
problematic.
|
NSNs
Model
|
Year
|
NSN
|
Mfg
|
Features
|
AN/PRC-112 |
|
5820-01-279-5450
|
|
|
AN/PRC-112A |
|
5820-01-280-2117 |
|
|
AN/PRC-112B
GPS-112
Hook-112
|
1995
|
5820-01-417-8752 |
Mot
|
applique adds GPS
|
AN/PRC-112B1 |
|
|
GD
|
App. adds GPS,
2-way messaging and encryption |
AN/PRC-112C |
|
5820-01-458-6018 |
|
|
AN/PRC-112D |
2006
|
5820-01-500-1535 |
EPS
|
GPS + AA batteeries
|
AN/PRC-112E
|
|
|
|
|
AN/PRC-112F
|
|
|
|
|
AN/PRC-112G |
|
5820-01-605-5854
5820-01-504-5465
|
GD
|
121.5, 123.1 MHz; 225–320
MHz; 406 SARSAT 406.028 MHz
|
Manuals
TM11-5820-1037-13&P
Patents
3656159
Minimum size Transponder, (Motorola), Apr 1972, 342/51 ;
327/176; 327/294 -
5394156
Digital range turn-around for tracking, telemetry and control
transponder, (Motorola), Feb 28, 1995 -
5726663
Survival radio interrogator, (Motorola), Mar 10, 1998, 342/419
; 342/357.09; 342/386; 701/213
Survival radio interrogator (1)
transmits upon request a message including an identification of
survival radio (3). Upon receiving and processing this message,
survival radio (3) determines its position from the Global
Positioning System and transmits a message back to the search
aircraft...
This is the GPS-112 and Quickdraw Interrogator.
Calls:
5365451 |
Mobile
unit
tracking system |
Motorola
|
Nov 15, 1994 |
GPS based
|
5389934 |
Portable
locating
system |
Business Edge Group |
Feb 14, 1995 |
|
5414432 |
Position
locating
transceiver |
Motorola
|
May 9, 1995 |
GPS, Iridium,
Mil-Sat
EAM
|
5438321 |
Location
system
(underground miners)
|
|
Aug 1, 1995 |
|
5515419 |
Tracking
system
and method for tracking a movable object carrying a
cellular phone unit, and integrated personal protection
system incorporating the tracking system |
Trackmobile |
May 7, 1996 |
|
5517199 |
Emergency
locator
device |
Aerodata |
May 14, 1996 |
|
6011510
GPS based search and rescue transceiver, (Motorola), Jan 4, 2000,
"Hook PRC-112" to add GPS to the PRC-112
Calls:
5334974 |
Personal
security
system |
|
Aug 2, 1994 |
Cell phone
|
5392052 |
Position
reporting
emergency location system |
|
Feb 21, 1995 |
|
5414432 |
Position
locating
transceiver |
Motorola |
May 9, 1995 |
GPS, Iridium,
Mil-Sat
EAM |
5418537 |
Location
of
missing vehicles |
Trimble |
May 23, 1995 |
|
5420883 |
Train
location and control using spread spectrum radio
communications |
Hughes |
May 30, 1995 |
|
5497149 |
Global
security
system (object track confirmation)
|
|
Mar 5, 1996 |
|
5502446 |
GPS-based
automatic
target reporting and finding network and components
(Rescue radio transmits on GPS L2 freq)
|
Trimble |
Mar 26, 1996 |
|
5517199 |
Emergency
locator
device |
Aerodata |
May 14, 1996 |
GPS
INMARSAT
|
5519403 |
Global
positioning
system communications multi-interface |
Motorola |
May 21, 1996 |
OMEGA
VOR
RADAR
TACAN
TRANSIT
LORAN
GPS
|
5526357 |
Communication
system and method for determining the location of a
transponder unit |
|
Jun 11, 1996 |
|
5563607 |
Time
and/or location tagging of an event |
|
Oct 8, 1996 |
|
5748147 |
Position
locating
rescue transceiver |
|
May 5, 1998 |
|
5847679 |
GPS
based search and rescue system |
|
Dec 8, 1998 |
|
7355513
Ultra-reliable personnel position locating system, Kenneth H. Brockel, et al (Army), Apr 8,
2008,
Class:
340/539.13 ;
340/539.11; 342/357.06; 342/357.07; 455/404.2; 455/456.1;
455/90.1; 701/213; 701/214
Is an improved method of using the AN/AYD-1 Personnel Locator
System by adding GPS to the search aircraft and using Time Of
Arrival and cooperating beacons between search aircraft to improve
the survivor location from about 100 meters to better than 10
meters.
This is the GPS-112 and Quickdraw Interrogator.
Calls:
5726663
Survival radio interrogator, (Motorola), Mar 10, 1998
References prior are PRC-112
"The search and rescue interrogators are typically suitcase
sized and include a GPS receiver, portable computer, LST-5 (UHF)
radio, battery, power supply, etc. and weigh approximately 60
pounds. This suitcase interrogator is also very
expensive."
5847679
GPS based search and rescue system, (Motorola), Dec 8, 1998 -
6020845
Satellite for increasing the utility of satellite communication
systems, (Stanford Telecommunications), Feb 1, 2000 - works with
TDRSS satellites
6552652
Rescue device, (Synergy Microsystems), Apr 22, 2003 - air dropable
vibration sensor equiped beacon w/GPS
6785553
Position location of multiple transponding platforms and users
using two-way ranging as a calibration reference for GPS,
(DirecTV), Aug 31, 2004 - transponder
7003278
Portable search and rescue system, (Tadiran), Feb 21, 2006
Related
Links
Mike Murphy
- often has the PRC-112() and/or Programmer
Cospas-Sarsat -
NOAA SARSAT -
AFCEA - SIGNAL -
Taking
the Search Out of Search and Rescue, By Henry S. Kenyon, May
2001 -
CBD -
JANUARY
3,2000 PSA#2507 - 37 ea. Program Loaders, P/N 01-P21700J001,
KY-913/PRC-112, NSN 7025-01-279-5308
Aeroflex -
RCTS-003B
Radio Communications Test System works with PRC-112, A, B,
B1, C, D and G versions
GD -
HOOK2
GPS Combat Search and Rescue (CSAR) System -
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