[Elecraft] KAF2 performance???

[k6se@juno.com]

David, N4IN wrote:

"Just got through using the KAF2, audio filter, working a few QSO's on
30M and noticed that my KAF2 performs better in AF1 than AF2 and that it
is also performing better with the wider xtal filter settings of 1.6kHz
and 0.7kHz.  Does this sound right or do I need to do some more aligning
of the audio filters with the xtal filters."
==========
No, it doesn't sound right.  AF2 should be slightly narrower.  It also
should be slightly louder because it introduces a couple of dB gain where
AF1 does not).

It works on all filter bandwidths, of course.  When turned off, it even
helps a bit on SSB (as opposed to not being installed).

I adjusted R1 and R2 on my KAF2 using a steady signal in CW mode (the
"birdie" at 7000 kHz with the antenna disconnected is ideal) tuned in at
the same pitch as my sidetone for loudest audio while AF2 is selected. 
The R1 & R2 peaks are slightly broad, but they are definitely there.

Another (better) way would be to monitor the same signal using
Spectrogram with a frequency mark at your sidetone pitch and the signal
tuned in to coincide with that frequency mark.  Adjust R1 & R2 while AF2
is on for max amplitude at the frequency mark.

Spectrogram will also show you if you have the BFO set correctly for each
CW filter bandwidth (i.e, with the received signal; tuned in at your
sidetone pitch, centered in the passband of each filter BW).

The KAF2 does a great job of enhancing CW signals, especially those weak
ones.

73, de Earl, K6SE
68 countries with K2 #2622 and counting.....