Different amplifier designs react completely differently from one another, so one never knows.
Here's another question... Do you have LED's in the RV, and have you experimented with turning them on and off?, it could even be a neighbor..
Somewhere on here I did a post complete with pictures of the MASSIVE RFI generated from an LED lamp I was testing, and most of the garbage was square in the VHF-TV/ FM band
(later)
Heres why I asked.
HERE is a link to the LED RFI test I did, and I remembered it correct. Channel 7 is among the worst when dealing with runaway RFI.