Yeah 61 PPM seems very high -what do you see the signal when you look at the spectrum plot
(you may need to use the +/- keys to bring the spectrum into view)
Try starting scope.py with no -c option at all (or -c 0), then look at the
"C4FM" display and the "data scope", and use the "fine tune"
slider to center the signal horizontally. You may need to try -c 5000 (or -c -5000) to
get the signal initially close enough so the slider is able to center it. Eventually you
should be able to come up with a value for -c such that the signal is centered without
needing to use the fine-tune slider... 45000 seems too high - I'd expect that about
+/- 10000 would be as much as you'd ever need at 800 MHz, but I haven't
experimented with the RTL yet...
Max