Carl Nimbus finally isolated it to this.
What do you do then? Sparky, our engineer, says create loops (3, about the size of 4 fingers wide) running into all your gear with any wires. Particularly the antenna into the transmitter (and at the base of the antenna.. which you should do anyway). This acts as a trap for the electromagnetics flying around and helps keep the area cleaner of 'spray'. We haven't implemented it yet, but once we try it.. we'll see if it works and let you know here.