Warning - There are satellites constantly monitoring 121.5 243.0 and 406 MHz and are designed to pick up the feeble signals from these survival radios. DO NOT Transmit on these frequencies unless you want to be visited by SAR personnel.General Information
Radio has been used as a way to call for help for many years. Although now discontinued 500 kHz was the international distress calling frequency for ships at sea. In modern times satellites monitor 121.5, 243 and 406 MHz. The early satellite systems gave a position, but the newer 406 MHz beacons transmit digital data about what kind of ship or plane is in trouble and possibly a GPS based location.
In the case of someone behind or near enemy lines there is a problem with rescue radios that work in the clear. The enemy may hunt the survivor by direction finding his beacon. The enemy may capture a beacon transmitter and use it to lure a rescue team into a trap. In all other cases these problems do not exist.
In some cases, like a pilot ejecting from a jet, you want the emergency beacon to turn on automatically. In other cases you want the survivor to turn on the beacon when they decide that's the thing to do.
SARSATIn the beginning they used Doppler to locate emergency beacons on 121.5 and 243 MHz. This service is scheduled to end next year on 1 Feb 2009. The current service is based on transmitters operating on 406.025 MHz using digital data including a transmitter serial number.
Will there still be a requirement for mil aircraft to have a "guard channel" at 243 Mhz? What about civilian aircraft guarding 121.5 MHz?
ArgosArgos is a unique worldwide location and data collection system dedicated to studying and protecting the environment. It's based on polar orbiting satellites and uses transmitters on 401.650 MHz that send digital data including a transmitter serial number. Mainly used for animals and environmental data like ocean buoys but also for expeditions and yacht racers. Based on the French Space Agency CNES. Animal transmitters are made by Sirtrack and others.
Emergency Position Indicating Radio BeaconPLB
For use on ships, they float. Simplified Voyage Data Recorder (SVDR) is and EPRIB.
Personal Locator BeaconELT
Civilian versions used by explorers, hikers &Etc. Military versions like the URT-44, PRC-112, C-SEL.
Emergency Locator TransmitterSSAS
Used in aircraft. Often have a "G" switch to turn on if a crash. Also have manual On/Off switch. Some stowed for use after crash.
Ship Security Alert SystemSEND
Allows calling for help if boarded by pirates.
Satellite Emergency Notification Device
Typically use Iridium satellite system. Used by hikers or explorers.
Typical brands: In Reach, SPOT, Spidertracks, RockSTAR, &Etc
These have very different capabilities and some may not be suitable if y our life is at stake.
MoviesIn the movie "Behind Enemy Lines" there a scene where the hero goes back to where the ejection seat landed and he gimmicks the beacon radio. But in reality the beacon radio stays with the guy on the parachute, it does not follow the seat.
AN/PRC-63This appears to use the same 14.0 Volt Mercury BA-1568/U that is used on the PRC-90.
eBay Photos: Mike Side, Label & both narrow sides, Antenna & Label close up -
Apollo Recovery Radio
A two channel radio was needed (the PRC-63 is a single channel radio). One channel to talk to the rescue aircraft and another channel to talk to the Apollo capsule.
NASA Tech Note TN D-7587 Apollo Experience Report - Development and use of Specialized Radio Equipment for Apollo Recovery Operations, Feb 1974 (pdf) .
AN/PRC-90 & AN/PRC-103, AN/PRC-106
PRC-90-2 Rescue Radio with 90BAv3 battery adapter
These radios are part of the bail out kit that aircrew members carry. It is turned on by the user, not automatically like the URT-33.PRC-96 Navy Lifeboat Survival Radio
The improved PRC-90-2 survival transceiver is familiar to most military aviators as the rugged, hand-held survival radio that has saved the lives of thousands of downed pilots and crew members. It has voice and beacon capability on the military distress frequency of 243.0 with voice Tx and Rx only on 282.8 MHz. 282.2 MHz is used by the Civil Air Patrol for ground - air coms with military aircraft during SAR operations.
The PRC-106 is a derivative of the PRC-90-2 and provides both beacon and voice Tx/Rx capability on the civil and military distress frequencies of 121.5 and 243.0 MHz, but does not have the 282.2 MHz channel.
The PRC-103 and PRC-195 are other derivatives of the PRC-90.
The AN/PRC-90 Legacy by Alan D. Tasker, WA1NYR - also has the PRC-106
Military Survival Transceivers - ACR PRC-90-2 and PRC-106 with table of specifications
PRC-90 Separate Web Page -
PRC-103 eBay photo -
PRC-112This unit replaced the PRC-90. It is a synthesized radio that covers 225 to 400 MHz and has a transponder function to help rescuers locate the radio. My guess is that when the location mode is turned on the radio turns on and off at a rate depending on how far it is from the rescue aircraft giving the aircraft range to radio.
The civilian and military have gone to the 406 MHz digital rescue radios that are supported by the SARSAT system.
The PRC-112 transmits the digital signal at 406.028 MHz. (SARSAT Report 708-1)
Major components to the AN/AYD-1 Personnel Locator System (PLS).
The PRC-112 has two fixed channels assigned to 121.5 and 243 MHz that can be used in either beacon mode or AM voice mode.
- SARSAT system.
- The KY-913/PRC-112 program loader loads the
- PRC-112 with frequency of operation (225 to 300 MHz) and a personal ID number (actually the SARSAT data set).
- The AN/ARS-6(V) is the aircraft system that interoperates with the PRC-112 giving the pilot either bearing or bearing and distance to the survivor.
- TS-4360 Test Set
It too uses a specialized BA-5312/U 3.4 AH battery instead of commonly available batteries, but there is an official battery adapter being developed by the government.
There are a large number of variations on the PRC-112. The later ones have a built in GPS receiver to allow reporting position. The design constraints for the PRC-112 are different than for a civilian survival radio in that the PRC-112 probably will be used behind or near enemy lines.
I doubt that the AN/ARS-6(V) can be used with civilian 406 MHz beacons.
If the PRC-112 is sending a SARSAT compliant digirtal message then it can be picked up by an enemy receiver, seems like a problem.
patent 5726663 Survival radio interrogator March 10, 1998, Motorola, 342/419 ; 342/357.09; 342/386; 701/213 -
Motorola - PRC-112 - was the origional contractor for the PRC-112 and General Dynamics has now taken over production.
General Dynamics Decision Systems - PRC-112B1 -
AN/PRC-112 COTS Battery for Navy Air Crews - after 9/11 the BA-5112/U NSN 6135-01-439-6229 was very hard to get
Survival radio on Space Shuttle - upgraded Motorola PRC-112
FAS - PRC-112 - Hook-112
PS Magazine - 3 item free upgrade -
Operation Allied Force (OAF) deployment order on 17 February 1999 to the completion of OAF in June 1999 - "VMAQ-2 aircrews were not issued the latest survival radios (PRC-112) prior to arriving in theater due to a DOD wide shortage."
Market Survey for the AN/PRC-112 Feb 2002
Ultra Life Batteries - BA-5312/U - Replaces the BA-5112/U
The CSEL will eventually replace the PRC-90, PRC-112, and the Hook 112 survival radios -- all of which are only capable of transmitting voice and in some cases data line of sight.
IFR Systems - RCTS-003 test set for survival radios
Indicator (Standard Embeddable Module) - voice crypto for the PRC-112
Cubic Defense Systems - AN/ARS-6(V) Data Summary - 225 - 300 MHz both passive homing (RPC-90) and active transponding with PRC-112 for range.
AF - Combat Survivor Evader Locator (CSEL) System - AN/PRQ-7 Hand Held Radio (HHR)
Pilot's widow files suit - not much of a case
Capt. Scott F. O'Grady used PRC-112 (rough plot of movie "Behind Enemy lines)
PRC-149 & URT-140
Beacons on 121.5, 243 and 406.025 MHz, voice on 121.5, 243 and 282.8 MHz and has a burilt in GPS position locating capability.
SAR radio for troops not forward deployed and recsue swimmers.
The URT-140 is the ejection seat beacon only version of the PRC-149.
Designed to run from a couple of ordinary "D" cell flashlight batteries or a sleeve holding a couple of "C" cells. There have been a number of reports about battery venting, sparking, etc. that has resulted in the development of a very special battery just for this radio. Also there's a problem when the radio is carried loose in a bag where it can get turned on accidently. A lockout clip has been designed as an add on fix.
SARSAT Report 703-1 shows two Saft "D" cells LSH-20.
2013 Notice of Intent for AN/URT-140
ProPublica: Adrift: How the Marine Corps Failed Squadron 242 Dec. 30, 2019 - Adrift video 12:11, Faulty Equipment, Lapsed Training, Repeated Warnings: How a Preventable Disaster Killed Six Marines -
RT-159A/URC-4Works on 121.5 mhz VHF and 243.0 mhz UHF. Uses 1 miniature and 5 sub-miniature tubes. Dual antennas can be used as a single whip or a double horizontal. eBay Photo - Manual is TM 11-510 November 1956. Korean conflict
Carried on the Viet Nam era Patrol Craft Fast (PCF).
Movie credits: Ice Station Zebra, The Bridges at Toko-Ri, Bombers B-52, Flight from Ashiya, Battle Taxi
URC-10 (see RT-10 below)
eBay Photos - A, B, C, D -
RT-285 A/URC-11Radio R/T RT-285 A/URC-11 Survival Radio, Cont. No. AF33 (604) 26183 Philharmonic Radio & Tel. Corp. Tuned to 243 MC. Has 4 Raytheon sub miniature tubes some are JRP 6397's and CK 6526's.+ Raytheon (2), 2N467 transistors. Battery is external via connector wire. Approx. 20" telescoping ant. eBay Photo -
URC-14Description said tubes and 121.5 MHz. eBay photo
URC-64U.S. Military Portable Radios by Alan D. Tasker, WA1NYR - has URC-64 information
Covers the 225 to 285 MHz range using crystals."The Air Force developed the URC-64 four channel device. The Army opted instead for the URC-68, a four channel two band (VHF/UHF) radio for helicopters that allowed downed airmen to communicate directly with ground troops as well as aircraft. Both of these were ultimately replaced by the Navy developed and improved PRC-90-1 and then -2 two channel unit (243 and 282.8 MHz), the first tri-service SAR radio." eBay Photo -Rescue of Bat 21 Bravo (Wiki) - "The URC-64 survival radio was his most important survival item."
Bat-21 (1985) by William C. Anderson
The Rescue of Bat 21 (1999) by Darrel D. Whitcomb
PJs in Vietnam: The Story of Airrescue in Vietnam As Seen Through the Eyes of Pararescumen, SMSgt Robert L. LaPointe, USAF, Retired - photo caption on back dust jacket "It includes a survival vest, two URC-64 survival radios, GAU-5 rifle, hand grenades, M-79 grenade launcher, .45 pistol, and three quarts of water."
BAT*21 - 1988 (IMDB)
Antenna: 6 section 21-3/4" (0.55m) 1/4 wave at 136 MHz
Battery: BA-1113, aprox. 1" dia x 4-3/4"
Case: 6-1/4" hi x 3-3/16" wide x 2-1/8" deep (27-5/8" with antenna extended)
Internal crystals (Fig 3):
In the above table I tried 2x, 3x and 4x the Crystal frequency, and 4x did work with an IF of 73 MHz. The x2 and x3 multipliers did not work (IF freq different for each channel), so I've used strike-through to mark them as non functional.
RF = 4 * Crystal - 73.0 MHz
Controls & Indicators
Top: Antenna (Fully extend to turn on) & Battery Test button
Front: Modulation analog meter ( also battery meter w/PPT), Volume, Mode (only Tone and Voice work, CW locked out), CHAN A, B, C, or D (the RELease button needs to be pressed to change channels. If the RELease button is pressed and channel B, C or D was already selected the channel knob returns to channel A), Speaker-Microphone
Bottom: two male snap terminals for earphone (with magnet to silence speaker), 1/4-20 threaded socket (attaches to camera tripod), swing out battery holder.
Left Side: Push-To-Talk button
Courtesy of : www.FlightHelmet.com
Courtesy of : www.FlightHelmet.com
Courtesy of : www.FlightHelmet.com
URC-68Radio Set, Rescue, Army, 38-42 and 230-250MHz, 4 channel, xtal control
Normally turned on by the survivor, but optional kit to allows automatic operation when a lanyard is pulled, like in an ejection seat.
URT-33D/M Beacon Radio set (Ejection Seat)This is a Vietnam era survival beacon transmitter (it has no receive capability). Commonly used in conjunction with the SDU-5/E Strobe light.
Maybe featured in the movie "Behind Enemy Lines"?
Featured in the book "The Rescue of Alpha Foxtrot 586" by Andrew C.A. Jampoler (Navy Institute Press).
MIL-B-38401A 16 Feb 1965 discontinued 7 July 1992
For use with AN/ARA-50 or AN/ARC-34 aircraft receivers.
The rescue beacon will jam the frequency (121.5 or 243 MHz) so it's not usable for other purposes. Note the PRC-90 has an alternate channel for voice communications so can be used even if 243 is active with a beacon.
AntennaThere are two possible antennas. The built-in telescoping antenna or the external flexable antenna. Only one antenna can be used at a time.
The flexible antenna is deployed in ejection seats along with a lanyard that turns on the radio when the seat ejects.
AN/URT-33C - w/o magents.
AN/URT-33C/M, 5826-01-099-6404 - A Magnet p/n A1-17-0672 added to actuation plug p/n A1-18-0921 forming automatic activation plug assembly p/n A3-06-0802 and a magnet p/n A1-17-0670 added to manual switch button p/n A1-18-0920 forming switch and magnet assembly p/n A3-06-0785.
NSN: 6135-01-50-3193LS Mercury for URT-33A
NSN: 6135-01-009-9135LS Mercury for URT-33A
BT-70129 AnMn (Alkaline)
NSN: 6135-01-050-3193 Alkaline, Eveready
These radios are built into the ejection seat survival pack. They automatically are activated when the seat ejects.
LCDR Castle Rescue in Laos by Nail, Sandy & Pedro 28 Dec., 1970- "The URT-33 is presently not connected to the aircraft because the kits required for the installation are not available, but VA-L5 will not connect them up automatically anymore. Since we feel that the VC have a sufficient number of radios that they can use to home on the beacon. Additionally the beacon virtually eliminates use of 243.0 until it is shut off, and if evasion is immediate the URT-33 might not be deactivated, and this could easily reduce or eliminate the possibility of radio contact." eBay Photo - URT-33B eBay Photo -
Ejection Seats - PRC-90-2 & URT-33 -
CBD ad - The beacon is a first alert device that activates upon separation from a disabled aircraft, and transmits a swept tone signal at 243 MHz. Approximate dimensions are 4.8 X 2.5 X 1.2 inches. Opportunities for improved performance include: ability to transmit on 121.5 MHz (civil emergency), 243 MHz (military emergency), 245 MHz (training), and 406.025 MHz (COMPAS/SARSAT); ability to operate normally and unassisted during parachute descent and after touching down on land or water; features to impair an adversary's ability mimic its signal. Beacons should be reparable by a commercial source, compatible with existing means of activation (magnetic plug assembly or remote cable and switch assembly), and interface with existing parachute harnesses, survival vests, and survival kits
URT-44 Over-the-Horizon COSPAS-SARSAT Personnel Locator Beacon
Replacement for the URT-33.
243 MHz with a battery that has a flange and slides into a slot.
eBay photo Front, Back -
PRC-63 & Apollo Recovery Radio
Radio 40.5 121.5
247.3 248.2 282.8 406.025
PRC-17,A - am mcw am mcw - - - - PRC-32 - - am mcw - - - - PRC-63 - - am mcw - - - - PRC-90,-1,-2 - am am bcn mcw - Y - - PRC-96 - am am - - - - PRC-103 - PRC-106 - am bcn am bcn - - - - PRC-112,A - PRC-195 - URC-4 - am mcw am mcw - - - - URC-10 - - am mcw - - - - URC-11 - - am mcw - - - - URC-64 - am mcw am mcw am mcw am mcw am mcw - URC-68 am mcw - am mcw - - - - URT-33 - - bcn - - - - URT-44
One Man Life Raft
See my One Man Life Raft web page.
ProPublica: Adrift: How the Marine Corps Failed Squadron 242 - 12:11 video.
Part of an email to ProPublica
In the subject video at 6:21 "He can't get his radio to work. The Marine Corps hadn't set it to automatically transmit location."
The drawing of a radio has the look and feel of the PRC-112, but really does not match it. Can you tell me the model of this radio?
Can you tell me about the option "to automatically transmit location"? What would trigger that?
It's my understanding that all aircrew members are issued an emergency strobe light. The one for Vietnam, Korea . . . was the SDU-5/E. Here's my web page for it:
I have sold thousands of battery adapters for this light so the military battery is not needed.
The newer rescue strobe light is the MS-2000 that uses a couple of common AA batteries instead of a very specialized military battery. Can you tell me if this is still being issued since it would have saved Resilard.
At 7:41 "In the seat of every fighter jet, there's a location beacon. It's purpose is to send out location information so missing aircrew can be rescued. Resilard's beacon malfunctioned in the water, sending no signal. In at least two previous accidents, this model (URT-140) stopped working when submerged in water."
Classically the ejection seat radio was just a beacon with no location information. That's to say it just transmits a wailing audio signal on 121.5 MHz (civilian frequency) and 243 MHz (military frequency). Aircraft radios have a "guard channel" that monitors one or the other of these frequencies. Also the original SARSAT (Search and Rescue Satellite system) listened to both of these frequencies and could determine a rough location based on the Doppler shift. This system has a big advantage in that the beacon turns on the instant the ejection seat is triggered. That means any nearby aircraft that hears the signal and can look around to see the parachute and follow it as it descends. This was common practice in Vietnam.
Because of a plethora of false alarms in this system it was abandoned by SARSAT in 2009 and a new digital system was started. The 406 Mhz beacon has a stored serial number that allows looking up what vehicle it is registered to, a contact phone number and a provision for GPS coordinates and other stuff.
But . . . it's the nature of the Global Positioning System that a receiver can take up to 15 minutes (cold start) to acquire all the data needed in order to provide a fix. As far as I know the PRC-112 and URT-140 are not tied into the aircraft buss and so will need some time before they can transmit a location.
Gibson Girl SCR-578/CRT3 BC-778This is a famous life boat rescue radio. Tx on 500khz and 8364 khz.
Also see my CRT-1B Sonobuoy web page.
"Cospas-Sarsat is a satellite system designed to provide distress alert and location data to assist search and rescue (SAR) operations, using spacecraft and ground facilities to detect and locate the signals of distress beacons operating on 406 Megahertz (MHz) or 121.5 MHz. The position of the distress and other related information is forwarded by the responsible Cospas-Sarsat Mission Control Center (MCC) to the appropriate SAR authorities. Its objective is to support all organizations in the world with responsibility for SAR operations, whether at sea, in the air or on land."
Users of the 121.5/243 MHz beacons will have until 2009 to complete the switch over to 406 MHz beacons.
Since 1982, more than 11,000 people have been rescued world wide with the assistance of the Cospas-Sarsat System.
Digital data beacon used in the CONUS -
ACR TerraFix 406 Beacon has 2 models one with and one without builtin GPS.
SDU-5/EThis is a personal strobe light typically carried by each aircrew member.
Can use my battery adapter instead of the BA-1574/U Mercury battery.
SDU-30This is a aircrewman distress marker light that uses a 3 Volt flashlight bulb and a special lens
Uses two each BA-1328/U batteries, can substuite two AA cells that have a modification.
For marking position or fratricide prevention
Note an IR light stick can be attached to a short parachute cord and spun overhead making a "buzz saw" that's very visible to searching aircraft.
AN/PRM-32A (TS-20)Uses two like kind PRC-90, -103, -106 radios with their antennas replaced with connectors on the test set.
TS-24BThis is a patented by ACR set that places the antenna in an RFI tight box and the antenna thinks it's talking to/from free space, but no signal is transmitted, thus not setting off a false alarm.
BT-2B Battery TesterFor testing survival radio batteries and also the survival strobe light SDU-5/E battery.TS-23 Light Output & Battery Tester
TS-884/PRM-30 used with the RT-159/URC-4. Has cable to connect to the battery and a similar cable to connect to the radio, plus a coax probe.
Basic needs in order: air, water, food, shelter, sanitation.
There are a number of ways of purifying drinking water (Wiki).
Purification tablets - aimed at disinfecting (killing bacteria). for example NSN: 6850-00-985-7166
2438781 Stabilized hypochlorite solutions and process therefor, Jonas Kamlet, Sep 7, 1944, Chloramine, Halazone - highly effective germicides
distillation - a way to purify water without the need for chemicals (sustainable)
LL-1 SunStill Type Mod I Mk 0 by Gailowhur
2402737 Process and apparatus for distilling liquids, Gailowhur Chemical Corp, Nov 12, 1942 - intended for survival at sea in wartime
2413101 Solar still with nonfogging window, Gallowhur Chemical Corp, Oct 20, 1943
Solar water disinfection (Wiki) - using clear plastic bottles
JJ-1 Seawater Desalter Kit - aimed at removing Sodium and Magnesium
1116038 Process of producing reactive zeolites, Permutit Co, Nov 3, 1914 -
2066271 Filter material and method of making same, Whyt Rox Chemical Company, May 27, 1935
2472616 Treatment of water, Permutit Co, Nov 12, 1943
2600719 Seawater desalting composition, Permutit Co, Dec 6, 1949,
Just a list, haven't studied or found current versions.
AFM 51-40 Air Navigation (19??)
AFM 64-2 National Search & Rescue Manual (1973)
AFR 64-3 Wartime Search & Rescue Procedures (1975)
AF Regulation 64-4 (1985) - Search & Rescue Survival Training - Elements of Surviving, Psychological...
AF pamphlet 64-5 (1952) - Aircrew Survival - Land, Sea, Sea Ice
AF pamphlet 64-5 (1969) - Aircrew Survival - unknown chapters
AF pamphlet 64-5 (1985) - Aircrew Survival - Checklist, Evasion....
AFM 64-6 Aircraft Emergency Procedures Over Water (1955)
AFP 64-15 Survival & emergency Uses of the Parachute (1983)
AFM 161-10 Field Hygiene & Sanitation (1970)
AFP 161-43 Venomous Arthropod Handbook (1977)
AFM 200-3 Joint Worldwide Evasion & Escape Manual (1967)
AARSM 55-1 Rescue & Recovery Operations (1978)
FM 5-20 Camouflage (1968)
FM 21-15 Care & Use of Individual Clothing & Equipment (1977)
FM 21-26 Map Reading (1975)
FM 21-26-1 Map Reading (1975)
FM 21-31 Topographic Symbols (1961)
FM 21-40 NBC Defense (1977)
FM 21-60 Visual Signals (1967)
FM 21-75 Combat Training of the Individual Soldier & Patrolling ( 1967)
FM 21-76 Survival Evasion & Escape (1969)
FM 21-78 Prisoner of War Resistance (1981)
FM 27-10 The Low of Land Warfare (1956)
FM 31-35 Jungle Operations (1969)
FM 31-70 Basic Cold Weather Manual (1968)
FM 31-71 Northern Operations (1971)
FM 90-3 Desert Operations (1977)
TC 21-3 The Soldier's Handbook for Individual Operations & Survival in Cold Weather (1974)
NAVPERS 16046 Handbook of Survival in the Water (1951)
Survival Kit -
First Aid Kit Individual -
One-Man Pneumatic Life Raft Survival Kits of World War II, R.S. McCarter & D. Taggart, 2006
ACR Electronics - radios & lights & test equipmentBack to Brooke's PRC68, Products for Sale, Military Information, Electronics, Personal Home page
Navy Advancement - Aircrew Survival Equipmentmen 1 & C, Aircrew Survival Equipmentmen 2, docs on line
Night Vision Systems - IR beacons
Prosar Technologies - lights & radios & test equipment - eBay intermercllc -
Equipped to Survive - SAR The Americas Conference Reports: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
page created 11 June 2001.