The Natl Broadcast network now operates on UHF frequencies... CH 7 and UP... This requires you to be more exact on pointing the antenna toward the transmitter station.
What we do that helps alittle bit is during the first phase of scanning in the digital channels if we do't start seeing digital station start counting up in the first 15% of the scan we will stop the scan and move the antenna a few degrees in either direction and restart the scan again. Here on the east side of the US where towns are closer together I guess we usually get between 6 - 36 digital HDTV station using our OTA BATWING with the UHF add-on.
Some folks have good luck with using a UHF HDTV signal finder like the SURELOCK which you can place in series with RG cable feeding the BATWING antenna.
Of course unless you can scan the digital TV signal into the HDTV unit you wont be able to view it. Not like the old analog TV days where you stick up an antenna and search around in all directions looking for a snowy picture to tweak up on...
The digital quality HDTV pictures are usually very good to view or almost nothing at all...
The fact that we can receive great quality full screen digital HDTV signals we use our OTA antenna at camp sites that have CABLE hookups so that we can get the local towns digital Natl Broadcast in full wide screen high def mode and then switch back to the cable side to watch cable channels. Its sort of like once you start watching full blown HDTV its hard to go back to standard tv signals.
Being in our off-road POPUP mostly we like to have the 24/7 radar channel up from the local towns to keep tabs on bad weather...
Oh some folk also like changing their BATWING antenna out for the JACK antenna. Good claims all around that it out performs the BATWING antenna. Installs in-place with the BATWING roof mount hardware. Still other folks have experimented with the multi-Bow Tie UHF type antennas with good results...
The best reception we ever got was with one of those $80 HD VHF/UHF high gain antennas from LOWES mounted on a pole to the side of our POPUP. This did great but was much longer than our popup was and would hit the trees when moving it around looking for TV signals. It also didnt last long as I had to take it down and fold it up before transporting so I finally broke off a couple of elements doing this and had to quit using it... Always got alot of looks from fellow campers...
sample photos from google images