a 1950s AN/APX6 Identification Friend or Foe device as used in aircraft. It's about 35 by 35 by 25 centimetres, painted matt black and has a hand-written Frequency Calibration chart on the front

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   Neil G4DBN (g4dbn@mastodon.radio)'s status on Tuesday, 02-Jan-2024 05:53:50 JST Neil G4DBN

   Look what followed me home from that ebay. Original early 1950s AN/APX-6 Identification Friend or Foe transponder. These were using during the Castle nuclear tests as well as in many thousands of aircraft, with a base station mounted on the X band radar systems. In the late 1950s, many were bought as war surplus by radio hams and converted to the 1.3 GHz/23 cm band. It makes over a kilowatt from a pulsed disc-seal triode and has a radioactive T/R switch and three explosive Destructors