[Elecraft] Frequency shift

[Julian (G4ILO)]

I don't know what results you got, Chas, but I tried Earl's method and it
didn't make the slightest difference here.

In fiddling around, I did apparently get the standard and narrow filters in
RTTY mode spot-on using the 14MHz birdie as a reference point. But
listening to actual PSK signals in the 14MHz band I found that switching
from wide to narrow would result in a frequency shift ranging from -4Hz to
+17Hz approx, depending on the frequency of the transmission being received
(in the 14.070 - 14.072 region.) This concurs with my understanding of the
effect of limited DAC resolution that have been explained to me by several
people, so I wasn't at all surprised. But I was prepared to give it a try.

Perhaps for some people who only use CW not PSK the frequency change is too
small to be noticeable by ear. Unfortunately it's still too great for
convenient use in data modes (which wasn't an application envisaged when
the K2 was designed, as several folks have pointed out).

The K2 mod I await most keenly is the one that gives better than 1Hz
resolution for both the VFO and BFO. :-)

73,
--
Julian, G4ILO. (RSGB, ARRL, K2 #392)
Homepage: http://www.qsl.net/g4ilo

Charles Greene W1CG@QSL.net wrote:

Earl,

I find it hard to believe you got all filters without a frequency 
shift.  If you send Julian a copy of the procedure, please include me too.