Newbie Question K2 CW Operation

[frank-142]

I'm thinking of ordering a K2 but I have some questions that I
cant find answered in the downloaded manual.  

1. The lowest cw pitch note is 400hz (which I think most prefer) but
the info I read in the manual states its best to use a pitch note
between 500 to 600hz for best results.   Does anyone have an idea
why that is the case?  

2. The manual states that the cw bandwidth can be selected from 200
to 2000 Hz.   If you were receiving a solid S9 signal, when you tune
through the signal is it possible to hear the other side of zero
beat at any filter bandwidth?  

3. If the DSP option is added does the audio DSP filter track the CW
bandwidth selection.  Or do you need to select them separately?

I would appreciate any comments or input.    Frank W7is


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[Don Wilhelm-3]

Frank,

See answers in-line below:

73,
Don W3FPR

> -----Original Message-----
>
> I'm thinking of ordering a K2 but I have some questions that I
> cant find answered in the downloaded manual.
>
> 1. The lowest cw pitch note is 400hz (which I think most prefer) but
> the info I read in the manual states its best to use a pitch note
> between 500 to 600hz for best results.   Does anyone have an idea
> why that is the case?

----------------------------------
The sidetone works just fine at 400 Hz - the components that shape the
sidetone to a sine wave have been optimized for the 500 to 600 Hz range (the
waveshaping components could be changed by juggling some component values).
----------------------------------
>
> 2. The manual states that the cw bandwidth can be selected from 200
> to 2000 Hz.   If you were receiving a solid S9 signal, when you tune
> through the signal is it possible to hear the other side of zero
> beat at any filter bandwidth?
-------------------------------------
There are 4 filter bandwidths available for each mode - each is adjustable
from about 200 Hz to over 2000 Hz, so you decide which filter widths will
work best for you.
The K2 allows you to set the BFO separately for each filter width and each
mode, and if properly set the opposite sideband will not be heard.
-------------------------------------
>
> 3. If the DSP option is added does the audio DSP filter track the CW
> bandwidth selection.  Or do you need to select them separately?
---------------------------------------
The DSP filter selection is independent of the IF filter selection.  If you
read further into the operation section of the manuals, you will discover
that tapping the XFIL button selects the IF filter while pressing the AFIL
button selects the DSP2 filter.  Yes, both functions are on the same
button - tapping the button results in a different function than pressing
(holding it down for a bit) the same button.
--------------------------------------

If that is not adequate clarification, please ask again.

73,
Don W3FPR
>


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[David A. Belsley]

On Feb 4, 2005, at 4:43 AM, frank wrote:

> I'm thinking of ordering a K2 but I have some questions that I
> cant find answered in the downloaded manual.
>
> 1. The lowest cw pitch note is 400hz (which I think most prefer) but
> the info I read in the manual states its best to use a pitch note
> between 500 to 600hz for best results.   Does anyone have an idea
> why that is the case?

Side tone is mainly a matter of preference.  However, the lower the
side tone, the greater the chances that the wider filters, which tend
to be centered on the side tone, will extend to the other side of zero
beat.  With the widest filters, you can avoid or mitigate this by
setting the side tone off-center, so that the filter skirts act on
zero.  Higher side tones make this easier and more effective.


> 2. The manual states that the cw bandwidth can be selected from 200
> to 2000 Hz.   If you were receiving a solid S9 signal, when you tune
> through the signal is it possible to hear the other side of zero
> beat at any filter bandwidth?

As mentioned above, with the wider filters, set the side tone lower
into the filter band pass so the skirts have an effect at zero.


> 3. If the DSP option is added does the audio DSP filter track the CW
> bandwidth selection.  Or do you need to select them separately?

The DSP and K2 filters are independent and must be set separately.  I
recall Lyle mentioning that he wished to have them linked, but there
wasn't room in memory (or something) that made that not possible at
this time.  Perhaps in the future.  Overall, you will find no real
problem with this, and there are times when the ability to set the two
filters separately is a decided advantage.


best wishes, (and don't hesitate to get a K2 -- it's simply a wonderful
piece of ham gear and a wonderful build),

dave belsley, w1euy


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[Vic K2VCO]

frank wrote:

> 1. The lowest cw pitch note is 400hz (which I think most prefer) but
> the info I read in the manual states its best to use a pitch note
> between 500 to 600hz for best results.   Does anyone have an idea
> why that is the case?  

The sidetone has the best sine-wave shape at about 500-600 Hz. with the
unmodified K2.  You can change a couple of components if you want to change it.
  The closer the sidetone is to a sine wave, the easier it is to use it for
zero-beating.

> 2. The manual states that the cw bandwidth can be selected from 200
> to 2000 Hz.   If you were receiving a solid S9 signal, when you tune
> through the signal is it possible to hear the other side of zero
> beat at any filter bandwidth?  

When you set it up you position the BFO so that the signal is in the lower part
of the passband so that you do not hear the other side of zero beat.

> 3. If the DSP option is added does the audio DSP filter track the CW
> bandwidth selection.  Or do you need to select them separately?

You need to select both the bandwidth and center frequency of the DSP separately.

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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[Bill Coleman-2]

On Feb 4, 2005, at 4:43 AM, frank wrote:

> 1. The lowest cw pitch note is 400hz (which I think most prefer) but
> the info I read in the manual states its best to use a pitch note
> between 500 to 600hz for best results.   Does anyone have an idea
> why that is the case?

The K2 standard is 600 Hz. You can pick a lower note if you want, but
this will increase the detection of the opposite sideband (beat note)
at wider bandwidths.

> 2. The manual states that the cw bandwidth can be selected from 200
> to 2000 Hz.   If you were receiving a solid S9 signal, when you tune
> through the signal is it possible to hear the other side of zero
> beat at any filter bandwidth?

I don't know about all the bandwidths. Note that for bandwidths much
greater than about 1 kHz, the shape of the CW filter is very
asymmetric, with an odd hump on one side. For this reason, I have my
FL1 bandwidth on CW to be 1 kHz.

At this bandwidth and 600 Hz frequency, the opposite sideband is not
audible with an S9 signal. (very faintly with an S9 +40 signal -- but
these are rare with the K2's scotch S-meter) It isn't audible at all on
bandwidths narrower than 700 Hz, nor is it audible with the OP1 filter
(the SSB option).

> 3. If the DSP option is added does the audio DSP filter track the CW
> bandwidth selection.  Or do you need to select them separately?

Unfortunately, you need to select them separately. It would be nice if
they tracked.

In general, I find that the CW crystal filter is sharp enough that I
never use the audio DSP filter. On SSB, however, the DSP filter does a
nice job of cleaning up the shape of the crystal lattice filter.

Bill Coleman, AA4LR, PP-ASEL        Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901

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