What does the switch located on the tv antenna coax plate, the one with the DC plug on it, do?

This is an amplifier for your tv signal when it is in the on position. I don't know if this works with the frequencies of high definition that is used today.
Try it in the on position with your HDTV converter box with the antenna up and the switch in the on position.
My converter box works great for the antenna signals when cable is not available.

The antenna doesn't know the difference between analog and digital. They are both radio signals.

Ok, I have another question, I just bought a new lcd flat screen, I don't need a converter box for that correct? I also modified a little, I split the signal after that cover plate and ran a coax to the front of the trailer. I hooked it all up and turned on the tv and turned on the power on the antenna, It picked up one channel without it on and none with it on. I did that in town (Greensburg PA which is about twenty miles away from Pittsburgh.) and then I went up to the Laurel Mountains and tried it there and got nothing. Am I doing it right? Or is there just no reception in the mountains? I've never tried it in a tent....;-)

you need antenna up and have to turn it to find stations

I didn't know it turned! Oh.... (head slap) that's the dial against the ceiling!!!!
Ya gotta bear with the rookie here....

lol you have to pull down on the ring why you turn it

Ya I figured it out, I never really looked at it closely. It still doesn't pic anything up, even the one I picked up in town isn't coming in. It was a little cloudy this morning I'll try it this evening.

if your flat screen is like mine you have to do a channel search every time you move the antenna

I got a channel, there is just bad reception. I live in town and there are two story houses all around mine and my trailer. I did a small modification and I didn't know if I screwed something up. The original coax wiring is on the port side just in front of the bathroom. I pushed the coax connector up through the cover plate, split it and ran one side to a seperate double cover plate and the other to a tv/cable switch, and then onto the front shelf in the nosecone. This gives me the ability to have the tv (antenna or cable service) on the frig or in the nosecone. For cable I wired the unused connector of the double coax cover and ran a jumper from that to the cable side of the switch, thus giving me the option to run a jumper coax from the external "supply" to the double coax cover plate and then onto the nosecone. I also installed a 400watt inverter in the cabinet just starboard of the factory stereo and installed a power receptacle in the shelf. Did I say all of that clearly?