Install the Directv box from your house into your coax system. My trailer has a coax outlet that has a short u-shaped coax cable on a cover plate. The top outlet is usually the input and the bottom goes out to the TV. I install the Directv box inbetween these two.
Setup the antenna by manually finding the 101 satellite. The coax will enter your trailer though the Cable In or Satellite In. You'll need a signal meter and a compass or an APP for your phone. Or you can spend some bucks and buy a Winegard antenna that finds the satellites for you.
Put the TV on channel 3 and keep the TV antenna setting on AIR as you're not using cable. Make sure that your over the air antenna booster is turned off (green light is out).
I've since upgraded to the Genie Wireless system using the Wingard Trav'ler roof mounted antenna that finds the satellites for me. The Travler is the only one that has HD for Directv. The wireless Genies plug in to the HDMI on the TV. It works great and each TV can get it's own channel unlike the standard box.
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