[Skimmertalk] Calibration of QS1R for latest SkimServer software

Pete Smith n4zr at contesting.com
Sun Mar 7 04:07:43 PST 2010

I wondered how you were calibrating, Wes.  I did it a little 
differently.  Using SDRMAXII, I tuned to 10 MHZ WWV.  Then (I just 
learned this trick), dragging the bar between the waterfall and spectrum 
display left or right with right mouse button held down enables you to 
"zoom" the display.  I zoomed way in and then adjusted the calibration 
number in the QS1R dialog of SDRMAXII, (actually reporting the actual 
clock frequency of the QS1R, I think) until the centerline was right on 
the center of the WWV carrier.  At this point the entire screen was only 
about 5 KHz wide, which made it fairly easy.

My resulting calibration number was 0.999994, which goes a long way 
toward explaining why your spots and mine were fairly consistently 
different in frequency by at least 0.1 KHz, particularly on 14 MHz and 

Even more fallibly,


Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com

On 3/6/2010 5:19 PM, Wes Cosand wrote:
> Folk have been asking question about calibration of SkimServer.
> Some notes from my experience:
> Of course since the resolution with which Skimmer Server reports the
> frequency is 100 hz, when I tune my HF rig  to the frequency reported in a
> Skimmer spot the HF rig is going to be off as much as 50 hz even when the
> QS1R is calibrated correctly.
> I assume my HF rig is correct, which may be a poor assumption.  I use CWget
> or some other software that reports the audio tone coming from my HF rig.  I
> click on a number of 14 or 21 mhz spots and write down the frequency of the
> CW tone as reported by CWget, average a number of them, and figure out how
> far I am from the CW offset tone of my HF rig
> When receiving with the HF rig if the audio tone of CW is too low when tuned
> to the frequency reported by Skimmer, then I raise the frequency correction
> factor in the Skimmer Server ini file.
> The last line in my SkimSrv.ini file is:
> FreqCalibration=1.0000095
> I think before the correction I was off by perhaps 100 hz or so on 14 Mhz
> Fallibly,
> Wes WZ7I
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