[Skimmertalk] CW Skimmer I/Q balance calibration

[Pete Smith]

Hi Dean - there is no balance editor, per se.  However, you can add 
additional data points in the same part of the spectrum where the bad data 
points are, and the calibrator will eventually let the majority win.  One 
way I have done this is to run my radio into a dummy load, and arrange the 
antenna on the softrock so that it gets enough signal to calibrate, but not 
so much that it goes into clipping.  It looks as if about a 25 dB SNR is 
needed.  Then you can tune the radio up and down the band, sending dits, 
and it'll calibrate quickly.

I discovered in the course of trying to bandswitch my softrock lite 8.3 
all-band version that the I/Q gain and phase corrections apparently are 
limited to about 20 degrees of phase difference - above that nothing 
works.  I wonder if a variation on that might explain your issue with the 
Delta 44?

Sounds like you are running multiple softrocks with Skimmer - I'd be 
interested in hearing more, for my upcoming NCJ article.  Have you used it 
in a contest?  How did it work for you?

73, Pete N4ZR

At 01:20 AM 12/1/2008, Dean R. Madsen wrote:
>Has anyone else noticed that when CW Skimmer runs using channels 3 &
>4 (the second of two input "ports") of a Delta 44 sound card, the I/Q
>balance function does not work (function is enabled, but no pixels or
>lines are plotted)?
>
>I had to change skimmer configuration and softrock to sound card
>connections to swap sound card input ports so the half of CW Skimmer
>copies that never calibrated would calibrate.
>
>Now that I have all receivers "calibrated", is there an I/Q balance
>editor to delete the errant pixel that throws the adjustment line
>into a parabola instead of a line matching most of the data points?
>
>Thanks,
>
>Dean Madsen - N0XR
>
>Dean R Madsen
>dean at acsnet.com          ICQ:5510840
>
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