[Elecraft] Re: Updated Version of Elecraft Keying Mod

Sat Apr 10 01:52:00 2004

If the edges are causing the key clicks and the rising edge is the problem
with the K2, then we would expect that the second derivative of the keying
envelope would show a larger peak at the beginning of the rising edge than
at the beginning of the falling edge.  The opposite is true.  The second
derivative at the beginning of the falling edge is 23% larger than at the
beginning of the rising edge.

So we have a falltime that is 50% faster than the risetime, and we have a
change at the beginning of the falltime that is 23% larger than the change
at the beginning of the risetime.  From this, I would conclude that the
trailing edge of the original K2 keying waveform is the primary source of
the key clicks.
-John
 KI6WX

----- Original Message ----- 
From: "Guy Olinger, K2AV" <[email protected]>
To: "John, KI6WX" <[email protected]>; <[email protected]>
Sent: Friday, April 09, 2004 12:55 AM
Subject: Re: [Elecraft] Re: Updated Version of Elecraft Keying Mod

> It was NOT the rise time. It was the leading edges, the sharp little
> edge or corner at the BEGINNING of the rise time, and the BEGINNING of
> the fall time, that were causing the clicks.
>
> The problem was with the SHAPE of the rise time, not the amount or
> length of rise time.
>
> 73, Guy.
>
>
> ----- Original Message ----- 
> From: "John, KI6WX" <[email protected]>
> To: <[email protected]>
> Cc: "Guy Olinger, K2AV" <[email protected]>
> Sent: Friday, April 09, 2004 1:09 AM
> Subject: Re: [Elecraft] Re: Updated Version of Elecraft Keying Mod
>
>
> >
> > ----- Original Message ----- 
> > From: "Guy Olinger, K2AV" <[email protected]>
> >
> >
> > > The leading edges were the killer in the K2. That's basically what
> > > Wayne fixed.
> > >
> > I have trouble believing this statement.  It is well known from
> circuit
> > design engineering that a faster risetime or falltime creates a
> wider
> > bandwidth signal.  The risetime of the original K2 keying circuit
> was 3
> > milliseconds and the falltime was 2 milliseconds.  So how does a 3
> > millisecond risetime create more key clicks than a 2 millisecond
> falltime?
> >
> > -John
> >  KI6WX