[Elecraft] K3: data modes - bizarre behavior

[Richard Ferch]

W4GRJ wrote:

> Just leave the K3 in USB, do not change to data mode. RMS Express will set to
> the correct freq. You will not have to make any adjustments.

If this is correct, and RMS Express tunes to the correct frequency in 
USB mode but not in DATA A mode, then there may be an error in RMS 
Express. DATA A is exactly the same as USB except for disabling 
compression and EQ and the default choice of input audio path (line in 
instead of microphone). In particular, the frequency display in DATA A 
and USB is the same. A setup that works in USB should work in DATA A 
without changes.

What I suspect might be happening is that RMS Express might be 
programmed to handle DATA A as if it were a USB version of AFSK A. In 
AFSK A, the K3's dial displays the RTTY mark frequency, whereas in DATA 
A the dial displays the suppressed carrier frequency. If the RMS Express 
programmers assumed that in DATA A the radio's indicated frequency was 
the center of the bandpass instead of the suppressed carrier frequency, 
they would program it to tune the radio 1.5 kHz too high in DATA A.

73,
Rich VE3KI