Posted by
Don Wilhelm-3 on
Nov 13, 2005; 11:47pm
URL: http://elecraft.85.s1.nabble.com/CW-Pitch-600-Hz-or-700-Hz-or-what-tp383635p383643.html
Paul and all,
Not that I am advocating it --- but the center of the CW filters is not
directly coupled to the sidetone pitch by the K2 firmware, so the CW filters
can be centered most anywhere.
It is quite possible to peak the CW filters at 1000 Hz (as long as you do
not run out of BFO range. HOWEVER, there are 2 problems with that - 1) the
sidetone pitch is limited to 800 Hz, and 2) the transmit offset is
controlled by the setting of the sidetone pitch, so that has a limit of 800
Hz as well.
So if one should center the CW filters on 1000 Hz, you could listen at that
frequency, but the sidetone would not be at that pitch (hard to zero beat),
and the transmit signal would be at least 200 Hz away from the received
signal.
I would also like to point out that the process of changing the BFO
frequency in CAL FIL is exactly the same as using a variable BFO control
(but it only varies while one is setting it).
The way I solve the 'wide CW filter lapping over onto the unwanted sideband'
problem is to center the next widest filter (FL2, usually 700 or 600 Hz
wide) first, and observe the placement of the low frequency slope in
Spectrogram (I position the cross-hair cursor there and click it), then I go
back and set FL1 to have the same low frequency slope as FL2. It works for
me (If you don't understand, I will add more detail).
73,
Don W3FPR
> -----Original Message-----
>
> >> Perhaps the enhancement could be a BFO that is adjusted by a front
> >> panel control?
> >
> > This would be nice, and I presume that you mean that the knob would
> > maintain the location of the BFO in relation to the passband along
> > with the sidetone pitch. Currently it's possible to adjust the pitch
> > from the menu (although this is not a one-knob operation!), but in
> > order to keep the selected pitch inside a narrow passband, you need to
> > do the CAL FIL procedure.
> >
> > So the knob that you refer to would have to cause the microprocessor
> > to recalculate the VCO offset that is used to place the selected pitch
> > at a given location in the filter passband. This is what happens when
> > you run CAL FIL.
> This is the one feature that I really wish the K2 had. My TS-940 and
> 756-ProIII both have this, and I find it very helpful. It's not only
> nice to be able to customize the sidetone pitch, but I like to tweak it
> easily via a front-panel knob every so often during long operating
> periods, like contests - adjusting the sidetone (and zero-beat point) up
> or down a little from time to time seems to help minimize ear (or is it
> brain?) fatigue.
>
> /Paul
> W3PH
>
>
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