I've had the same issue. I've experimented with various antennas such as indoor amplified, outdoor amplified with rotor and outdoor omni-directional amplified. I've had the best success with an amplified outdoor with rotor like this one:
https://www.ebay.com/itm/HDTV-Antenna-Amplified-Digital-TV-Antenna-150-Miles-Range-360-Rotation-Outdoor-/202078442770?epid=912188818&hash=item2f0cd05512:g:~4kAAOSwna1ZzJl-
This has the best gain and pulls in the most channels, IMO. However, having an antenna like that in an RV is not practical because the elements are fragile and tend to break. So I got one of these 'flying saucer' outdoor antennas:
https://www.ebay.com/itm/HD-8000-360-Degree-HDTV-Digital-Amplified-Outdoor-TV-HD-Antenna-VHF-UHF-120Mile/182594054244?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Not quite as good reception but it can be mounted permanantly on an RV or placed on a tripod (which is what I do).
