I have found all three parts of the UHF Homer adaptor AN/ARA-25 that was used on the early military UHF aircraft radios like the ARC-27, ARC-34 and ARC-52.

The system is now integrated in my ARC-52 installation but so far without proper functionality. 

I have found  a service document labeled: Electronics UHF homer adaptor AN/ARA-25 

that includes a wiring diagram of the ARA-25 in combination with the ARC-34 radio.

It also contains a functional description and block diagram but unfortunately no schematics of the AS-578A/ARA-25 antenna or the AM-608/ARA-25 amplifier.

Anyone here that has schematics available or perhaps knows more of the functionality of the ARA-25?

Nico - PA3ESA