The key part is the mind of the operator ... with practice and not a
little determination its amazing how good the mental filter gets. So
if you cannot afford an OMNI-VI with all bells and whistles, the
situation is not hopeless ! Low pitched CW signals are definitely
much easier to separate than high pitched ones, and at my age, they
are a lot pleasanter to listen to as well.
Narrow bandwidths are great as long as all the signals in the net stay
on the same frequency. But when guys jump around, or are
drifting/chirping (obviously not TenTec gear) then a wider bandwidth
is nice to have. I'll stick with 500 Hz for general use. But I still
have to test an MFJ DSP audio box. Maybe that will eliminate some of
the high pitched hiss that annoys me ... I can reduce it a lot with
the Omni-V audio filter, but I am sure this wideband hiss comes from
the IF amplifier strip AFTER the 500 Hz (or 250 Hz) filters. On SSB
its not at all noticeable, of course. Its most evident if you back off
the RF gain to the point where antenna noise vanishes and you can
hear whats left.
The deluxe answer is another filter (two poles would do) just before
the product detector. The German filter manufacturer KVG makes just
such a 9 mHz filter to cut down IF-generated noise, but don't ask me
how or if one could be added to an Omni-V.
Yes, QSK is great. But its also good for SSB. Properly set up VOX (or
even intelligent use of a PTT foot switch) makes for a more natural
conversation, with pauses, so that others can chip in without waiting
for a gap at the end of a long over. Its not natural to talk for 10-15
minutes non-stop, is it ?? I am certainly not encouraged to do it at
home. But not many seem to use VOX the way it was intended to be used.
That reminds me; I once checked into a local net and then drove 40
miles during one single continuous over. At that point I managed to
call in again, this time to sign out ...
Listening is a neglected art.
John G3JAG
On 22-Apr-99 Roy Koeppe wrote:
>
> Some personal thoughts from my experiences in CW rag chewing for
> the past 43
> years. Round tables are fun. QSK is the only way to fly. That's why
> telephones are duplex and folks sitting around talking in your
> living room
> don't stick their fingers in their ears while making long monologs!
>
> But, to prevent fatigue, you need a quiet background. This is best
> accomplished NOT by turning down the RF gain, but instead by using
> extremely
> narrow bandwidths. I use two 250 Hz filters in my Omni-6+ (one is
> the new
> model 212 which is centered on a lower, 500 Hz CW tone). Then the
> PBT
> control is adjusted for the low pitched side, and the DSP LP filter
> is set
> for 600 Hz cutoff. The DSP noise reduction is always on, and CW
> off-set is
> set for a 420 Hz tone. The result is a virtually silent background
> with a
> nice soft nature to the lower pitched tones. Even QRN crashes are
> soft
> sounding. In addition, the mind can more easily separate lower
> pitched CW
> signals from one another than it can higher ones. This is because
> low tones
> are numerically proportionally spaced further apart.
>
> Enjoy, K6XK
>
>
> --
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Date: 23-Apr-99
Time: 00:14:27
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