If you are using the antenna that is on the trailer, then yes. There is a button that powers up booster. Normally located just behind where the TV sets, next to where the coax hooks on. When it's powered up there is a little red light that will come on.
2008 Cruiser CF26RK
2013 Ford Eco-Boost
Heavy duty payload - Max tow
As you probably found out, (just for the sake of someone else reading this), the antenna booster needs to be OFF (light out) if you're trying to receive cable. Otherwise, the amplified antenna signal will override most/many cable signals.