looks like the source of RFI is the Yaesu, shut 'er down
another case of funky grounding and a hot "ground" in the shack is what it sounds like. do you have a common bonded ground between the equipment in the shack? you know, the wing nuts, braid, and all that? might have to run that to a ground rod since you don't have one from coax to the static arrestor to ground rod with a balanced line.