There are a few "Indoor Antennas" out there. the latest and greatest per the TV ads is good old fashion RABBIT EARS like from the 1970's.. What can I say
Limited range and if you are living in a metal RV forget about 'em.
The winegard Sensar IV is my first and only recommendation
It is amplified (Means stronger signal delivered but it also amplifies noise so this may or may not be a plus) it is HIGHER than any other RV antenna (See notes) and it is directional (Giving it more range) it outperforms a Jack at the same height.
Height is might . I proved that back one day in 1978 when I was chatting with some far off ham radio operators and another ham tried to join in. he did not make it. HE was running about 160 times the power I was running and he did not make it (I could see his house from the 21st floor observation window) I had the HEIGHT (about 250 feet)
The only thing better is a Residential high gain antenna mounted on a TALLER mast.