 AN/UPN-1

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.