[Elecraft] K2 Filter Shape Factors

[Bill Tippett]

VE7CLA wrote:
 >Is there a similar optimization for offset/sidetone
frequency? Other than personal tonal preferences, what are the
advantages and disadvantages of the offset/sidetone set to 400 Hz vs.
600 Hz vs. 800 Hz etc?

         Really no major advantages/disadvantages other than
what works best for your ears.  I find a lower pitch works
best for me with very weak signals.  Some say that is because
the differential between signals sounds greater.  For example,
if two signals are 100 Hz apart, if you are listening at 600 Hz,
700 Hz QRM is only 17% higher.  If you are listening at 300 Hz,
400 Hz is 33% higher, supposedly allowing your between-the-ears
DSP to better discriminate.  Whatever the reason, I find a very
low tone works best and frequently set my old TS-930S or Orion
to ~250 Hz for extremely weak signals.  Beginning in the 90's,
most radios have a lower limit of 400 Hz, although a few go
down to 300 Hz.  The TS-930S Pitch is continuously variable down
to zero beat and the Orion goes down to 100 Hz in 10 Hz steps.
I seldom find anything below 240 Hz works well for my ears.

         Contests are a different situation where you may be using
a wider BW filter to hear stations that call off-frequency, so
I often choose a 450 or 500 Hz pitch, allowing me to better hear
stations that call up to + and - 400 Hz off-frequency.  Of
course you can only play this game when the band is not packed
with strong stations every 500 Hz!

         Unfortunately it is not simple with the K2 to quickly change
the Pitch setting and have the BFO's automatically track the
filters.  More expensive radios do this in firmware as well as
offering PBT, but who's complaining for $599?

                                         73,  Bill  W4ZV