Looks like QRM from something nearby. Could be via the Coax, Antenna, or via (through) the plastic enclosure. Is the RXR
sitting next to the video monitor, or Vdc lines from a switching power supply or a UPS?

I have seen a bad ground connection in a USB cable ( open from one end to the other on the shield ) give terrible QRM. Have you tried a different USB cable?

I also had to wrap my RSP1A in copper foil to reduce external QRM sources. Not sure it the mfg applied any screening to the DX model.
From the image, it appears to about 350 KHz apart, which is little wider than the normal switching power supply QRM.

73 Kriss KA1GJU