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The AN/UPN-1 was a radar Pathfinder radio beacon used by the United States Army Air Forces and Airborne forces during World War II.


Radar beacon AN/UPN-1, sometimes known as BUPS (Beacon, Ultra Portable, S-band), is an ultra-portable radio beacon for ground, paratroop or shipboard use having a range of 35 to 50 miles. The set is capable of being interrogated by airborne radars operating on beacon function and replying with a coded signal permitting the beacon to be located in range and azimuth. It is capable of transmitting five different codes, it transmits on 3256 Mc. (Megacycles [per second], now MHz (Megahertz)) and receives on 3333 Mc. peak power output is 50 Watts.


  • RT-72 Transponder assembly
  • CY-220 case
  • MX-242 harness
  • CY-221 chest
  • CY-222 battery case
  • PP-116 Rectifier battery charger
  • MX-253 harness
  • AS-172 antenna assembly
  • AS-171 antenna assembly
  • CX-237 cord
  • CG-92 cord
  • AB-49 antenna support
  • CY-225 case

See also[edit]


  • TM 11-227 Signal Communication Directory. dated 10 April 1944
  • TM 11-487 Electrical Communication systems Equipment. dated 2 October 1944
  • Graphic Survey of Radio and Radar Equipment Used by the Army Airforce. section 3 Radio Navigation Equipment Dated May 1945

External links[edit]