[Milsurplus] APS-13 Questions

[Mike Morrow]

>The APS-13 is a pretty famous set, but there seems to be little
>information on it around.

You could find more info searching for "RT-34/APS-13."  Some information and a schematic can be found at:

http://www.nj7p.org/cgi-bin/millist2?mode=normal&name=RT-34

The AN/APS-13 operates near 415 MHz, 0.5 watts average (450 watts pulse) output (from two 6J6 tubes).  It is similar to a simple pulsed radar altimeter and provides only a simple warning light and bell warning to the pilot when a reflected signal was detected out to about 2500 feet behind the aircraft.  This was valuable for night fighters.

Apparently, the actual use of this system as a tail proximity warning radar was short lived, for it was believed that the 415 MHz signal that was emitted served to attract attacking aircraft to the night fighters on which it was installed.

Some interesting AN/APS-13 info (including pictures of the antennas) in its conventional role is summarized at:

http://www.duxfordradiosociety.org/restoration/equip/aps13/aps13.html

An innovative use of the AN/APS-13 by RAF fighters for targeting the V-1 flying bomb is at:

http://www.hawkertempest.se/storymonica.htm

The ultimate use of the AN/APS-13 was in the ground proximity triggering systems of the two atomic weapons that ended WWII.  Each bomb used four RT-34/APS-13 units, modified for different frequency ranges to avoid mutual interference, in a voting scheme to detonate the weapon below 2000 feet above the target.  Some interesting details of this application can be found at:

http://cryptome.org/nuke-fuze.htm

Mike / KK5F