A pair of cross coupled NAND gates as a 'switch debouncer' should be
useful?
Geoff
GM4ESD
----- Original Message -----
From: "Don Wilhelm" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <elecraft@mailman.qth.net>
Sent: Thursday, January 04, 2007 2:54 PM
Subject: RE: [Elecraft] something is bugging me, K2 keying problem.
I may be proven wrong someday, but I believe that 'problem' is caused by
contact bounce at the key (or bug). Cleaning the contacts may not be
sufficient, and it will vary from keying device to keying device depending
on the type and condition of the surfaces at the contact area.
I cling to my contact bounce theory because it rarely occurs if the diodes
are connected to a computer output.
I have heard that a tiny drop of NoOxIt or similar product on the contacts
helps, but I have not tried it myself.
One idea (although it makes things more complicated) is to key a mercury
wetted reed relay (if you can find one) with the bug and drive the diodes
with the relay contacts. The mercury wetted contacts do not bounce (well,
they could but it is greatly reduced). The other thing that works is to
use
an external keyer (I use the K1EL K12 keyer) which has a separate input
wired for the hand key.
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