K2: diodes for using straight key?

[dw-4]

It seems I read somewhere that there is a diode mod for the K2 so that a
straight key can be input into the unit along with a paddle and the K2
can tell the difference and one can use both keys?

Or was I dreaming :)

N1BBR
--
 [hidden email]

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[Brian Mury-3]

On Sat, 2010-02-06 at 20:31 -0800, dw wrote:
> It seems I read somewhere that there is a diode mod for the K2 so that a
> straight key can be input into the unit along with a paddle and the K2
> can tell the difference and one can use both keys?
>
> Or was I dreaming :)

You were not dreaming! The K2 will treat a simultaneous contact closure
of both the dot and the dash lines as a straight key. The two diodes are
there to eliminate the short circuit that would otherwise exist between
the two sides of the paddle, which would cause a contact closure on
either side of the paddle to ground both sides (and therefore be treated
as a straight key as well).

The circuit is on page 95 of the K2 manual. There is also a menu item
that you will need to ensure is turned on.

73, Brian
VE7NGR


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[David Pratt]

In a recent message, dw <[hidden email]> wrote ...
>It seems I read somewhere that there is a diode mod for the K2 so that a
>straight key can be input into the unit along with a paddle and the K2
>can tell the difference and one can use both keys?
>
I agree with Brian, this arrangement works quite well, although I use a
pair of 1N5821 Shottky diodes in place of the 1N4148 and have also wired
a 0.47uF (474) capacitor across the straight key.  Without the capacitor
I got unpredicted errors, possibly caused by stray r.f. in the shack.

My only regret is that the K3 does not have a menu option to accept my
K2 dual key assembly. Consequently, I have to use a different key for
the K3.

73
--
David G4DMP
Leeds, England, UK
------



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