Did you just recently upgrade to LED lights...  Those did me in until I got rid of the REGULATOR TYPE LED boards and went with the non-regulated cheap ebay/china boards. All is fine now...  Even having the modern outside LED trailer running/stop lights might be interfering as well..
Another source of strong RFI interference is the RV INVERTERs if you are using one...
Of course I'm sure you are tuning in your TV reception the correct way by setting your HDTV menu to "ANTENNA" and turning on the 12VDC feed up to the OVER THE AIR antenna built-in PREAMPLIFIER and then doing the search for digital TV signals everytime you stop somewhere...
Its not like the old analog TV days anymore...
Roy Ken