It's definitely not just your problem.  The display code changed in the
latest versions to enable the zoom/pan features that came along with the
wider display.  Because of this, we have to use a more flexible manner of
converting a pixel on the display to a frequency.  Unfortunately the
resolution of these pixels is very poor.  Consider that when running 96kHz
on the 1x zoom, the display is showing 40kHz of data.  This data is spread
over 704 pixels.  This means that each pixel represents 40,000 / 704 = 56Hz.
What this means is that the accuracy of those frequency readouts is only
going to be ~56Hz in that setting.  It gets worse when you go to 192kHz and
zoom out further than 1x.

The long and short of it is that this needs to be reworked in the code to be
calculated more accurately.  I'm not sure how we will do this, but I'm sure
we can improve on the current situation.


Eric Wachsmann
FlexRadio Systems

> -----Original Message-----
> From: Larry W8ER [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, January 17, 2007 2:20 PM
> To: FlexRadio - Eric; flexradio@flex-radio.biz
> Subject: Frequency Calibration Problem
> 
> I have three versions of Power SDR available. They are PowerSDR 1.6.3
> (with K6JCA mods), PowerSDR 1.8.0, and PowerSDR latest SVN.
> 
> There are three groups of numbers below the panadapter. First is hz
> deviation of the frequency of the strongest signal in the filter
> passband. Second is that signal's strenght in dbm. Third is the
> frequency of the strongest signal in the filter passband.
> 
> I start PowerSDR 1.6.3 and tune the receiver to WWV (15 mhz). Going to
> the setup/calibration tab, I put 15.000.000 in the Frequency calibration
> Window and hit calibrate. The main screen comes back and shows me [0.0
> Hz -73dBm 15.000.000 Mhz]. This is what I would expect it to show.
> 
> I start PowerSDR 1.8.0 and do the same thing. Now the display gives me
> [-20.2 Hz -73dBm 14.999.980 Mhz]. It appear to be telling me that WWV is
> 20 Hz low. The same is true of the latest SVN code.
> 
> I have tried reloading the program. I did not import the database but
> started with a new database and fresh calibration each time. Each of the
> PowerSDR versions is in it's own directory with it's own database.
> 
> I have checked the KB. I have checked the reflector and seem to find
> nothing on it so it seems to be only my problem. Any ideas???
> 
> --Larry W8ER



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