Jumpy FFT Display with SDR# R1651

Ian DXer
 

Probably a video would be better at displaying this problem, but my description will have to suffice for the moment.

Setup:
Windows 7, 64 with Airspy HF+ & SDR# r1651
Tested Spectrum: 88-108MHz - not tested outside this spectrum.
Modulation: WFM
Bandwidth: 768kHz
Firmwear: Original (upgrade will happen sometime later)
Zoom Level: Minimum as usual

This is an usual problem & I'll do my best to describe it.
On the upper spectrum/amplitude display(FFT) (above the waterfall display) I note for maybe, 70% of the chosen frequencies
in the spectra of: (eg 88-108MHz) that at either end of the 768kHz BW (just outside the 768kHz bandwidth) that the amplitude of the noise floor are randomly jumping up by around 10dB
(jitter) Even within the 768kHz passband the noise floor (and maybe signals?) appears to be jumping up/down (jitter) by 1-3dB where they shouldn't.
At the edges of the passband jitter amplitude is random between 3-10dB.
Visually this is very distracting to the point of giving one a headache.
This fault was NOT evident on previous r1646 or any previously SDR# releases that I've used in the past.
I can partly negate the far end 10dB jumping by moving the zoom slider control up slightly so as not to see it, but still have the slight 1-2dB or 1-3dB jumping
of the display within the 768kHz rxer bandwidth.

I suspect this fault occurs more often in areas of the band where there are many strong signals, but I still find exceptions.
This is particularly a visual distraction at 768kHz bandwidth.

If I go back to using SDR# r1646 or earlier no problem. If I return to SDR# r1651 the jitter (for want of a better description) is there on most channels for
FM BCB.

Has anyone else noted this?
Or can others test for this with SDR# r1651 on FMBCB at 768kHz BW?

 

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