the first thing to make sure is that you have a digital TV or a digital converter if not. assuming you have that, since it worked in another RV. there should be a Antenna booster located in the RV somewhere, usually in the bedroom.
Most airlines in the United States, including American, Delta and United, allow carry-on bags that are no more than 22 inches long, 14 inches wide and nine inches high. Southwest and JetBlue accept a more generous 24 inches by 16 inches by 10 inches, and JetBlue even adds a couple more inches for cabin bags flying on its Airbus A320 planes.
Delta also notes that its carry-on bags may not exceed 45 linear inches, including handles and wheels and adds, Baggage must fit easily in the carry-on baggage check (approximately 22 inches by 14 inches by 9 inches or 56 by 35 by 23 centimeters), which is located near the check-in counters..