[ARC5] Creating a Connector for the DU-1

[David Stinson]

The output connector for the Navy DU-1 Loop Direction Finder
is about as "unobtainium" as you can get, so I decided to make one.

The thread on the connector is odd-ball.  The only one I know of that
matches is the weird antenna connector for the BC-312 / BC-342
series of Army receiver.  I did happen to have one of  those.
The DU-1 output connector uses a single banana plug to connect
to a run of coax.   The internal parts of a crimp-on PL-259 looked
like a good candidate for "fiddling."
I took a banana plug from the end of a cheap test lead.

Here are the pre-fiddle connectors:
http://home.netcom.com/~arc5/DU1Conn/DU1C1.JPG

and the salvaged parts:
http://home.netcom.com/~arc5/DU1Conn/DU1C2.JPG

The thread on the PL-259 is a bit thick and takes up 
some of the thread space in the final connector.  
Every millimeter counts, so I filed-down the two 
"pointy" ears on the PL-259 and trimmed it flat.
Needed to enlarge the center hole for the banana plug.
The "right" hole was about 3/16ths, but I didn't have 
that drill around here.  So I used a 15/64ths and back-filled
the void afterward.  Seemed to work fine.
 Here's the trimmed and drilled PL-259:
http://home.netcom.com/~arc5/DU1Conn/DU1C3.JPG

And the banana plug mounted on the coax center:
http://home.netcom.com/~arc5/DU1Conn/DU1C4.JPG

And here's the finished connector:
http://home.netcom.com/~arc5/DU1Conn/DU1C6.JPG

Since "modern" banana plugs seem to be smaller,
I did have to flex-out the leaves of the plug to 
make good contact, but seems to be working well.

73 DE Dave AB5S