In order of performance you wend .. Straight off the edge of the cliff.
Odds are the power to the roof is non-existant as the other person said.. THis can be caused by such things as not knowning how to turn it on (Will explain) or a blown fuse.
How to turn it on method 1: Wall plate
Many RV's have a Wall plate, normally near the TV that is nearest the Rooftop antenna. it has a 12 volt outlet, a switch, a Light, and an antenna connection.
Light on antenna on, Light off cable selected
Some have a box of many buttons, you push a button that is in a group called 'MAIN TV' for example and the button says ANT or Antenna.. On the left is a button marked POWER, that's it.
Some have both.. In which case it's the wall plate.
SOME. very few, have a switch, by itself, may say WINEGARD on the mounting plate.. That's it.
No 12 volt to roof = no booster (Pre-amp) since it's in the antenna head on the roof.
Best antenna for long range reception
Winegard WITH Wingman and repalce the wall plate with a SENSAR PRO.
What I use.. See last sentence.