Assuming you have just the CW or the USB or LSB button pressed, this sounds odd. You haven’t got AFC activated or synchronous AM on have you?
The other thing is the ‘DC spike’. Look at the two frequency displays (LO and VFO) and check they are not the same. Receiving on the same frequency as the LO will cause all manner of funny effects, including fluttering and distortion.
This reply was modified 2 years, 5 months ago by .