Search And Rescue Radios ( Sorted Chronologically )
DH4PY

To the Picture Gallery

 

 

 

      AN/URT-27
  AN/URT-33
      MR-506

 

 

 

 

 


The units shown here:
 

  • AN/URT-33 (1983*)
  • AN/URT-33A (1982*)
  • AN/URT-33C (1984*)
  • AN/URT-33C/M (1987*)
  • AN/URT-33B-1
     
    are Emergency Locator Transmitter (ELT), or "radio beacon"
    Here you see five different versions of AN/URT-33. The device normally is activated at bailout and sends a signal for quick location of the pilot.
     
  • A tone oscillating between 300 and 1000 hertz is sent two times a second.
     
    AN/URT-33 is used for locating the pilot, the pilot talks to the rescue team by help of his SAR radio.
     
    There are two disadvantages:
  • The constantly sweeping tone jammes the frequency;
  • The beacon can be pinpointed by the ennemy.

    The picture gallery shows the development up to integrated circuits.
     
    The year of issue is not known to me, the (*) refers to labels "replace battery".
     

    The aging ELT or radio beacon are replaced by:
  • Emergency Locator Transmitter (ELT) with three frequencies:
    (121.5; 243; 406 MHz).
     
    The aging SAR- radios (like PRC-90) are replaced by:
  • Personal Locator Beacon & Voice Transceiver (PLBVT), with the same three frequencies as ELT.

     


    Technical Data:
    Frequency:
    243 MHz, crystal controlled
    Output power:
    Continuous operation for 3 hrs : 150 mW
    Controlled operation for 15 hrs : 200 mW
    Range:
    180 Miles, the SAR aircraft at 10.000 ft
    Modulation:
    Pulse carrier
    Frequency sweeping from 1000 to 300 Hz 2 times a second
    Activation:
    automatic, manual override