If you have this type WINEGARD BATWING crank-up antenna with added dipole you probably have the best you can get.
This antenna has a built-in PRE-AMPLIFIER controlled by the Antenna WALL PLATE Panel by pushing in a button on the Wall Plate. You also have to switch your HDTV mode to ANTENNA and rescan again after pointing this antenna to the local towns.. I regularly get excellent HDTV reception from both Washinton DC TV towers and Richmond Virginia TV towers sitting here at my house in Northern Neck Virginia. Both towns are over 50 miles away from us.
The problem is the newer RVs coming out seem to be using the ONMIDIRECTIONAL stationary low profile antennas that are not getting good reviews by the RV community...
These round looking low profile antennas only work good when you are right on top of the local transmitting town.
Roy Ken