If the above suggestions fail to get you any reception, check the cable connections at the TV and booster too. The connector on the back of the booster panel was broken on our trailer, they're pretty cheap, and had it replaced under warranty. I rarely watch over the air TV, and generally find the recpeption poor or nil where we go camping.
The fixed antena Surveyor uses on most of their trailers is the omni-directional type. Yes it is fixed, requiring no cranking up or down or rotation.
The "older" style crank antennas do need to be cranked up and down, and are directional. This means they can be rotated to better recieve signals from a certain direction. This generally results in better reception from a particular transmission tower as compared to the omnidirectional fixed antennas.