TS-24B survival Ratio Test Set

© Brooke Clarke 2001 - 2007

TS-24 Survuval Radio Test Set

General Information

This is a test set for the following Emergency Location radios (Frequency MHz):
DC module
ext Voltage
24-RC/PRC-90 24-BAM/PRC-90
24-RC/PRC-90 24-BAM/PRC-90
24-RC/PRC-90 24-BAM/PRC-90
24-RC/PRC-90 24-BAM/PRC-90
24-RC/URT-33B 24-BAM/URT-33B

It was made by ACR Electronics that has a line of emergency location beacon radios and related products.  That is logical since it tests only emergency location beacon radios.  Note that any one can test their radio during the first 5 minutes of the hour, but that is not a practical thing to do if you are in the business of working on these radios or if you are part of the crew of an aircraft that's about to take off and you want to know that your survival radio is working.

It is made under patent  US04278979 07/14/1981 Method and apparatus for testing survival radios

"A test apparatus is disclosed which is particularly adapted for testing survival-type radio transmitters in the field. The apparatus includes an enclosed metallic test chamber into which the antenna of the radio transmitter is placed. A movable load carriage within the chamber  applies a load to a predetermined point on the antenna which results in simulating in the test chamber the radio frequency absorption/reflection characteristics of the antenna in free space. A direct measurement of the radio frequency energy absorbed by the load is thus indicative of the performance of the radio transmitter and its antenna in free space."

"Moreover, a receiver responding to a test transmitter within the chamber at a location of 150 feet from the chamber or more may be regarded as a serviceable receiver. This may be used as a test for operation of receivers intended to operate with the survival radio."

Major Component Parts

Test Chamber (Left, Right)

This is the subject of the patent.  It allows testing the transmitter is such a way that the signal does not leave the test chamber.  It also allows taking another radio about 150 feet from the chamber and seeing if the signal can be heard since the attenuation of the chamber is about - 35 dB.

Radio Cradle Assembly

This is a bracket that is customized to hold a specific type of radio.  There is also a speaker that can feed a known audio power level into the microphone of the radio under test.  The 24-RC/PRC-90 is shown and works for both the PRC-90 and PRC-106 radios.

RF Module

There are two functions for this module, testing the transmitter output power and modulation and testing the receiver.
This module can be powered by external 13.5 VDC or by a cylindricalBA-1568 survival radio battery.

D.C. Module

This is to check the battery for each of the radio types listed above and to drive the speaker.  The 24 socket connector on the end without a label is for the battery adapter.

Battery Adapter Module

A 24-BAM/PRC-90 is missing.  It has a 21-pin plug and a cylindrical battery simulator that goes into the battery socket on the PRC-90 or PRC-106 radio under test.  See the above table for Battery Adapter Modules to be used with other radios.

To make a 24-BAM/PRC-90 battery adapter use a Cinch P321CCT connector.

In the Cinch 21 pin rectangular connector:


This is a test set that was from a government auction at Fort Campbell Kentucky.  This is the home of the 101st Airborne Division and it is really an active base.  I don't know what individual division had used this unit.   It was made by ACR Electronics that has a line of emergency location beacon radios and related products.

The description for this set was: Here is a Radio Test Set that was designed to test several different military portable radios. Some of the radio types that this unit was used to test are URT, URC and PRC.

Photo Overall -  the indentations look a lot like the shape of the bottom of a PRC-68 or PRC-126 radio.
Photo Label - The address above for ACR Electronics matches the one below for the CAGE Code

Other Survival Radio Test Sets

AN/PRM-32A (TS-20)

Unlike the TS-24, this set does not test the antenna along with the radio.  The good thing about not using the antenna is that the test will not generate a false alarm.

This is the government test set for the PRC-90 and PRC-106 Survival radios. "Requires one radio as receiver and another as transmitter. Tests 243 MHz frequency for beacon, transmitter MCW-voice and receiver outputs. Also Tx-Rx voice outputs for 282.8 MHz (PRC-90) and 121.5 MHz (PRC-106), earphone & battery test. Has 1.8" square meter with Red-Green scale, TX-Rx connector adapters for hook-up & operator's info. 3x5x4, 3 lbs."
at Fair Radio. - Photo
 eBay Photo, Accessories - The TS-20 is made by ACR.
ETM on line Manuals:
036228.pdf  TM 11-6625-2632-24P-  RADIO TEST SET, AN/PRM-32A (NSN 6625-01-013-9900) (THIS ITEM IS
037755.pdf  TM 11-6625-2632-14-1  RADIO TEST SET, AN/PRM-32A (NSN 6625-01-013-9900) (THIS ITEM IS
TB 43-180 has calibration instructions for this test set.

The -14 manual has opertion instructions for the test set.  The test set needs to have 2 like radios, one is used as a transmitter and the other as a receiver.  The antennas are removed from the radios for use with this test set.  An RF detector/power meter measures the Tx output.  A small amount of the Tx signal is feed to the Rx which is driven from an antenna simulator circuit.  The -24 manual is just the parts list for the test set.

BT-2B Battery Tester

Mike Murphy Photos: Tester, label - made by F.A.S. Systems corp.

Survival Radios

In the case where the survivor came from a military jet ejection seat the automatically operated URT-33 may be used.  The problem with this is that it will be transmitting a beacon on 243.0 MHz making that frequency unusable until the URT-33 is turned off.  It also may draw enemy troops to the downed pilot.  Most survival radios have an earphone for use where there may be an enemy nearby.  Beacon means a sweeping audio tone designed to attract the attention of someone listening to the guard channel.  MCW is an abbreviation for Modulated Continuous Wave and is an audio tone that can be heard in a receiver operating in AM mode.  It's the way morse code is sent on these radios.

AN/PRC-90 & AN/PRC-106

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.
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-only on 282.8  MHz.

The PRC-106 is a derivative of the PRC-90-2 and provides both beacon and voice capability on the civil and military distress frequencies of 121.5 and 243.0 MHz. The PRC-103 and PRC-195 are other derivatives of the PRC-90.
The AN/PRC-90 Legacy byAlan D. Tasker, WA1NYR - also has the PRC-106
Military Survival Trancivers -  ACR PRC-90-2 and PRC-106 with table of specifications
PRC-90 Seperate Web Page -
PRC-103 eBay photo -
PRC-90 eBay photo -


U.S. Military Portable Radios  by Alan D. Tasker, WA1NYR - has URC-64 information

This radio is part of the bail out kit that aircrew members carry.  It is turned on by the user, not automatically like the URT-33.

"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."
BAT-21 - "The URC-64 survival radio was his most important survival item."


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."
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 downon 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


IFR Systems, Inc. - makes a test set for the PRC-112, PRC-90 and URT-33
Army Radios - SAR Radios -

Personnel Recovery Radio Programs - 1999 - many different radios mentioned for different tasks and locals:

Radio Where Deployed
PRC-112, B Combat SAR forward troops
PRC-90 Combat SAR not forward troops
URT-33 Beacon in tatical aircraft ejection seats
PRT-5 beacon in multi-place life rafts
PRC-125 rescue swimmers
PRQ-7 CSEL Future Combat SAR forward troops
PRC-149 Future Combat SAR not forward troops
PRC-149 Future rescue swimmers
URT-140 Future Beacon in tatical aircraft ejection seats
AN/ARD to AN/ARN - Equipment Listing - AN/ARD-19 is the Automatic Direction Finder; used with AN/URT-33
Fleet AW Association - Chapter 5 - Rescue and Survival Equipment -
Approved Navy Training Plan for Avation Lifr Support Systems, 1997 mentions a number of radios:
AN/URT-33 Beacon
AN/PRC-90 Voice & CW
AN/CRT-3 hand crank, CW key
AN/PRT-5 beacon floats HF & UHF
THe AN/PRC-149 uses a Trimble Lassen LP GPS receiver and transmitts location information on 406 MHz (COSPAS/SARSAT), it also supports 121.5 and 243 MHz.


Both ETM on line Manuals are restricted
066111  TM 11-6625-3203-23P   RADIO TEST SET TS-24B (NSN 6625-01-128-8588) (REPRINTED W/BASIC
067784  TM 11-6625-3203-13    RADIO TEST SET TS-24B (NSN 6625-01-128-8588) (THIS ITEM IS INCLU
TO 33D7-71-42-1 Operation and Maintenance Instructions with Illustrated Parts Breakwown, 1 April 83, Change 1, 15 Oct 84 - but no circuit diagrams

Government Records

NIIN search found:
 U/P: $10119.75  U/I: EA  WEIGHT:
            SOS     Status      StopSee      Conflict     WS
 Army:  B16         A                                 No         QA
 USAF:     FLZ    A                                 No
 DEPRA: 00     CDATE: 01004    Phrase:             AAC: J
 DEMIL: A       PLOA: 22             PSC: U             SUPREC: NO
 PMI: A             DVD:                    QUP: 1             IMC: D

CAGE search found:


CAGE CODE: 18560, Status: A - Active, DUNS Number: 080170350, Voice Telephone: 954-981-3333, FAX  Telephone: 954-961-4403, County: BROWARD, Date CAGE Code Established: 10/25/1974, Last Updated: 09/14/1998

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