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Sdr freq / center ?

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Premium Subscriber
Feb 17, 2003
New York
I use the fast scanner plug in and noticed then on some entries, it will list the freq and then on some, not all, it has a different freq in center as seen in the pic below. When I started out, I was using 2 10.00 ebay dongles. One ppm was 44 and the other was 77. Now I use an Air spy Mini.

Question is, whey is the center freq different on some, but not all, and will it affect any scanning using an airspy that has no drift?




Apr 8, 2005
Springfield MO
No, it just means that you weren't using the function of SDR# that keeps whatever frequency you're actually tuned to dead center on the frequency spectrum (the top portion). If that option is disabled (by clicking the tiny icon at the right side of the actual frequency display at the top) it will cycle through 3 options:

- center tuning (looks like two arrows pointing inward towards a vertical line, spectrum always shifts to place the tuned frequency directly on the red indicator line)

- free tuning (arrows pointing outward, no line), and sticky tuning (a pushpin, wherever you tune the red indicator line will then mark that spot, spectrum doesn't shift)

- sticky tuning (pushpin, and to be perfectly honest I don't know exactly what the hell this option is supposed to do)

It sounds like you're confusing the PPM adjustment on the actual physical sticks with the center frequency offset on the SDR software you're using, and they're not technically related so it's not a concern to be honest.
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