[Milsurplus] primative IFF

[Ray Fantini]

I am kind of fuzzy about the how all the old IFF stuff worked. I can understand how in the sixties and beyond they built systems using computers to read, format and display IFF data that was pushed onto the radar video but have no idea how the older IFF stuff operated. Did things like the APX-6 have inputs for aircraft identifying data? Or any flight crew modifiable settings? And at the ground end how did ground crews see the IFF data? Was it displayed on the same display as the radar data? Was the old equipment good for anything beyond friend or foe only identification? On the KC-97 at the Dover Mobility museum there is an APX-6 installed in the back of the flight deck along with a modern altitude encoding transponder located in another part of the cabin. Perhaps there was a period of time both systems were used together although would think that because they both work in the same band that they cannot be on at the same time.
Ray Fantini KA3EKH