Other than matching the existing one and replacing it with the same, that's all I can say.
There are antenna boosters that are offered for sale and they seem to work for 50% of the people who buy them. They either help or they don't . 50% hasn't made me want to go out and try it because they are so site and luck dependent even in the same campground.
We started with DirecTV and now use Dish (they are now cheaper, but I wouldn't hesitate to go back). For this reason we don't worry about a signal booster any more. So much so I still don't own a digital TV receiver now required to interpret the digital TV waves. Don't forget to check out if you need one of those.
travelrving.... your comments are for satelllite TV. The OP is for a signal booster, used for boosting the over-the-air antenna for FREE TV, not subscription.
The digital receiver we are referring to is the device that is supposed to interpret the new digital tranmissions done by TV stations these days.
We answered to replace the signal booster with the same as what's there. Then there are aftermarket boosters you can buy to even boost the over-the-air signal some more for within your RV which may or may not work. Finally, since all the stations have converted to digital you MUST have a digital receiver for the RV antenna to receive any Free TV stations. I hope this clears up what the OP wanted or needed, but I don't believe satellite TV (costly subscription) is what the desire.
I hope we don't stray too far off topic. My first post mentioned satellite TV because I may not have enough experience with over-the-air signals since I have not used the antenna since before the digital conversion so RVAdventure might have the best and cheapest recommendation.