Yes, the booster button must be off for cable, and on for antenna reception.
But, if that is not your issue, and I say this because I had other issues too... get a good piece of TV cable, test it at home so you know it works, and run it through the window at the RV Park directly to your TV.
If it works, then screw the connection onto the unit and connect inside with the booster off. If it doesn't work, you know it's somewhere in the wiring.
What I found, after going through this exercise was: I went into the false panel to the connection that comes from the cable outside and is the cable to my wall connection inside the camper. When I unscrewed the cable, I noticed that the center pin in the connection was shorter than usual... about 1/8th of an inch shorter... so when I screwed the cable onto the connection, the center pin was not actually connecting to the terminal.
I put my needle nose pliers onto the center wire and pulled it out that little extra bit. After I screwed it back together, it has been long enough now for several years.
mike
