Posted by
Don Wilhelm-4 on
Sep 29, 2007; 2:58pm
URL: http://elecraft.85.s1.nabble.com/Best-CW-Pitch-tp453907p453909.html
Drew,
There is nothing electrically preferred by the K2. If your BFO range is
adequate, the pitch can be set anywhere the BFO will support - and that
will usually allow a filter center frequency up to 1000 Hz.
However, look at the KAF2 and KDSP2 options for their upper frequency
centers (currently 800 Hz upper limit). A few capacitor and resistor
changes can move the KAF2 anywhere you want, but the KDSP2 would need
modified firmware to change its upper (or lower) limit.
While we are on the subject, I might say something about very low
pitches (since it has been mentioned) - there is a limit to how low you
can go and still retain the single signal reception because a
significant amount of the filter passband crosses over from zero Hz
pitch to the other sideband. In the extreme, you end up with the
response like a Direct Conversion receiver where the same pitch can be
heard (at equal amplitudes) on both sides of zero. One must consider
the IF filter skirt slope when deciding how low the filter can be set
while still retaining single signal reception. That is a situation that
potentially exists for any receiver, it is not unique to the K2. The K2
variable filter skirts do have a reduced slope at wider bandwidth
settings, and I suggest using Spectrogram (or equivalent) to observe the
actual filter slope when adjusting for a low pitch - make certain the
low frequency slope of the filter remains above zero Hz.
73,
Don W3FPR
[hidden email] wrote:
> I was wondering, is there an electically optimal sidetone pitch which
> the K2 prefers?
>
>
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