[Collins] How to homebrew a keypad control interface for the KWM-380

[LeeCraner at aol.com]

Adding a frequency control keypad to your KWM-380 greatly increases the rigs
flexibility, allowing you to directly key in any frequency as well as store
10 frequencies (or 100 if you have the Kiron board).  The keypad also
substantially reduces wear and tear on the tuning speed pushbuttons.

These keypads are available from both Surplus Sales of Nebraska
(www.surplussales.com) and Pipo Communications (www.pipo.cc).  However, the
keypad requires the Collins AC-3803 Control Interface, the DB25 connector on
the back of the KWM-380.  These interfaces are no longer available new and
are hard to come by used.

Fortunately, these interfaces are easy to homebrew with just a handful of
readily available parts.  Adding the homebrew interface does not permanently
modify your rig and it is easily removed should you decide to sell the rig
later.

I've written a step by step article on how to build the interface, complete
with pictures and schematic.  If you would like a copy, simply drop me a
line and I'll email it to you.  (Be warned, it's a big file though).

This is the third (and probably last) article I've written on modifying the
KWM-380.  The two previous articles, "Provide a Tune Function for Antenna
Tuning" and "Add a Keypad to a Collins/Turner Microphone" are available for
download at the Boat Anchor Manual archives:  http://bama.sbc.edu/ and Ron
Baker's Collins website: http://www.wb4hfn.com/ .

73
Lee WB6SSW