With the dB (from 0 to -60dB) vs Hz (from 0 to 160hz) charts from analogue initial observations of equipment testing:

  1. Equipment testing of analogue scope of states: ATSC on, ATSC off, ATSC off and power unplugged and ATSC off power unplugged and audio cord unplugged.

The laptop was determined to be the cause of the noisy signal. I swapped a laptop to one that had grounding and since then have been observing a clean signal.