[Elecraft] K2 vs OMNI V keying waveform?

Wed Apr 30 22:11:48 2003

Wish it WAS intellectual.

Listening on an MP with INRAD 400 Hz filters in 2nd and 3rd IFs,
hearing my particular K2 (1239) on 28.4 at S9, tuning up/down 500 Hz
will have clicks 15/20 db above the noise. This would cover up a
signal at the noise level otherwise copyable.

This is very easily seen with Spectrogram listening to the MP. It is
also easy to see that the receiver is completely rejecting anything
more than 250 Hz up or down, with zero bleedthrough of the K2 main
signal. The passband, and the click content is completely obvious in
the display.

This exact same test with a click-fixed MP transmitting instead of the
K2, receiving on the same MP, shows no change from RX in the
spectrogram listening up/down 500 Hz.

A receiver with less rejection of adjacent signals would have more
difficulty.

Clicks are not really apparent when listening to a signal ON its
frequency. Tuning above or below a signal will make clicks stand out
if they are there. But if a K2/100 was driving a KW and it was coming
in 20 or 30 over 9, the clicks in the same situation would be 35-50 db
over the noise.

We definitely need some circuit adjustment to narrow the transmitted
K2 signal. It does not have to be mushy at all, just needs the
transitions on the CW waveshape to be 4-5 ms with no sharp edges.

Guy.

----- Original Message ----- 
From: "David A. Belsley" <[email protected]>
To: <[email protected]>; <[email protected]>
Cc: <[email protected]>
Sent: Wednesday, April 30, 2003 9:21 PM
Subject: Re: [Elecraft] K2 vs OMNI V keying waveform?

> Oh boy, this one is likely to start a line.  But I have never
(repeat,
> never) heard anything approaching clix from a K2 -- and I've worked
a
> bunch.  This is so for either the K2 or the K2/100.  Now I know
there are
> those who say the drop time is too fast, but this seems to be an
> intellectual finding only.  Indeed I imagine I am not alone among K2
owners
> who get pretty constant compliments on the keying, and I often get
people
> who say they can tell a K2 by the enviable keying.
>
> best wishes,
>
> dave belsley, w1euy
>
> --On Wednesday, April 30, 2003 4:45 PM -0700 [email protected] wrote:
>
> > Doc, K0EVZ wrote:
> >
> > "How do the output waveforms of the K2 vs the Ten Tec OMNI V/VI+
> > compare?"
> > ==========
> > The Omni V and the Omni VI have decent CW waveforms (no klix), but
the
> > Omni VI+ has bad klix.  Apparently when Ten-Tec upgraded from the
VI to
> > the VI+ they did something to the transmit AGC loop that buggered
up the
> > CW waveform.  I understand that some hams have done a mod to the
VI+ to
> > alleviate the problem.
> >
> > I haven't tested my K2 for klix, but I understand that the K2 has
a
> > slight click problem.  Too fast of a transition on either the rise
or
> > fall time.
> >
> > When I say "klix", I mean that the CW bandwidth is on the wide
side.
> > When tuning in on the clicky signal with a narrow CW filter, you
can hear
> > the clicks 1 or 2 kHz before the signal is in the passband of the
narrow
> > filter.
> >
> > 73, de Earl, K6SE
> > _______________________________________________
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>
>
> ----------------------------------
> David A. Belsley
> Professor of Economics
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