[Skimmertalk] IF Offset Explained?

[Pete Smith N4ZR]

I have been doing some experimentation, using the wideband IF output of 
my K3 and various programs for displaying I./Q data from an LP-Pan 2.  .

Is there a good clear explanation somewhere of the meaning of the setup 
value described variously as Audio IF (CW Skimmer), IF Offset (SO2SDR by 
N4OGW), and Global Offset (NaP3)?  There is an explanation in the CW 
Skimmer help file, but it is not very helpful, because it seems to be 
based on the old transceiver design with roofing filters placed before 
the downconversion.  Alexlimits his Softrock-IF mode to 24 Hz for this 
reason, but that restriction is no longer relevant to radios like mine

In particular, I am trying to understand why, using the same sound card 
and the same bandwidth, these programs come up with different value 
needed to placeCW traces at the correct frequency, so that you can click 
on them and move the transceiver correctly.  They range from -6144 Hz 
(CWSkimmer and NaP3)to -1290 Hz (SO2SDR).  I would have thought 
thevalues would be established by the transceiver's IF setup, but I 
guess not.

-- 

73, Pete N4ZR
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