[Milsurplus] DU-1 DF Loop

[Mike Hanz]

Todd, KA1KAQ wrote:

>One of the things I'm still looking for is the little DU-1 DF loop and
>coupler unit. Did any other companies other than Bendix make these?
>

Not to my knowledge.  It was actually a commercial unit (Amelia Earhardt 
is shown in one photo with what looks like the prototype in her arms) 
that was later Navy nomenclatured.  It went through the normal series of 
improvements over the years...DU, DU-1, and DU-2.

>Although I've seen a few over recent years (when I wasn't really
>looking for one), I don't recall seeing examples from other
>manufacturers. IIRC, they pull power from an accessory socket located
>in the associated system (RU/GF, ARB, etc).
>Any information is helpful, any if anyone has a spare or unused
>example laying around that needs a new home, I'd certainly like to
>hear more.
>

You can see the schematic, parts list, and a photo at 
http://aafradio.org/docs/docs.html .  The end of the cable that connects 
the DU to the RU is a strange pigtail-ended coax made from the armored 
flex cable of the time with a single conductor running inside.  It was 
fasted to the front side of the RU using an Adel clamp, with the pigtail 
inserted into the RU antenna connection. Not pretty, but functional.  
The connector on the DU end is unique, having a 11/16"-24 thread (have 
never encountered that on any other piece of equipment.)  I included 
fabrication dimensions at the bottom of the page.

73,
Mike de KC4TOS