I had a similar problem when I resurrected an old dongle that I wanted to use as a spectrum analyser. On testing on the local FM station, the audio had tiny gaps in it about every half second. After lots of fiddling I tracked it down to the FFT resolution for the display set too high - way up the top. I set it right down to 512, the audio was distorted but not chopped, so I gradually increased the resolution until I got the choppiness again and backed it off one step - it's now set on 16384 - I guess that's samples per second.
Don't tell anyone but I used SDRSharper :wink: