Ours was a 2008 RV and it had the tube type (non-HD) TV and the old antenna that was not optimized for HD signals. We upgraded to a flat screen HD TV and installed the full Jack antenna system with the signal strength meter and the Jack Antenna amplifier.
The result was 9 additional channels we can watch sitting in our driveway. Plus, don't have to worry about lowering the antenna...have started down the road with the antenna up before.
It was a pain replacing the old antenna. Removing all the stuff, enlarging the hole for the Jack antenna and resealing everything. But it was worth it.
It appears that the new Winnebago units are now shipping with the Jack antenna. No more cranking up and down. We really like ours.