[Elecraft] Best CW Pitch???

Don Wilhelm w3fpr at embarqmail.com
Sat Sep 29 09:58:00 EDT 2007


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

drewko1 at verizon.net wrote:
> I was wondering, is there an electically optimal sidetone pitch which
> the K2 prefers?
>   
>


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