[ARC5] R23 repair, dynamotor mounts, questions...AN/ARN-9

[Mike Morrow]

>> These posts beg a question, or two.  I understand the 90/150 Hz VHF and UHF
>> LOC and G/S but how did this VHF-only system (ARN-9) work?  Or, was is
>> horizontal guidance only?

That is one question that is NOT begged!  :-)

I wrote in my last post about the LF/MF navigation receivers (R-23 etc.):

> It supplies filtered AF through the MX-19/ARC-5 audio adapter installed in the > receiver for use as the MF localizer to the AN/ARN-9 "Air-Track" ILS (improved > ZA, ZA-1, ZAX).  Major components of the AN/ARN-9 are:
>
> R-43/ARN-9 VHF glide-slope receiver/ILS converter
> ...
> ID-24/ARN-9 Cross-needle indicator

The R-23 or R-24/ARC-5 provides reception of the MF localizer signal and sends it to the AN/ARN-9 through the MX-19/ARC-5 audio adapter.
The R-43/ARN-9 provides reception of the VHF glide-slope signal, and contains the ILS converter that processes both the MF localizer AF and the VHF glide-slope AF for display on the ID-24/ARN-9 cross-needle display.  The Air-Track ILS used 90 to 95 MHz for the VHF localizer signal.

It was all just an improved version of the pre-WWII USN ZA and ZA-1 ILS.  Jack Antonio is probably the only person who has assembled a complete ZA ILS.  The ZA used a RU-* receiver for the MF localizer.

Mike / KK5F