Does sound like a loose RG cable connection to me. These kind of things usually either work or they don't - not intermittent...
The next time it happens take a quick look outside and make sure the RED LED LIGHT is 'ON' under the JACK Antenna... If it is NOT ON then do a quick inside the the trailer where the ANTENNA PANEL is located and make sure it has it's LED LIGHT ON.
The JACK Antenna is great antenna and alot of folks swear by it. I like the BATWING Antenna myself but that is probably just OLD SCHOOL taking over that you need more wire in the sky to get best reception.

This JACK Antenna would be pointing to the distant HDTV signal to the RIGHT.


If you do end up getting this BATWING Antenna be sure the UHF DIPOLES are included. This antenna would be pointing to the HDTV Transmitting station to the RIGHT. Changing to this antenna would only be a five minute job since you already have the same crank-up and rotate assy installed.
Roy Ken