Is your antenna in your RV connected to the radio? Where is it located? You may or may not get similar reception to the car. Nowadays, cars have their antennas (typically, shark fins) located at the back end of the roof where there is nothing to shield it from the signals - and a nice metal ground plane at the antenna base. If your RV radio antenna isn't on the roof with a decent coax lead to the receiver, you are not going to get much signal.
My A-frame has a 5" rubber ducky stub antenna mounted next to the door on the side of the camper, about chest high. Doesn't get squat for reception, but I don't really care enough to do anything about it. I did check that the antenna was connected when I installed a power switch in the stereo leads.
2019 Flagstaff T21TBHW A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time
last trip: Twin Lakes, Colorado
next trip: Cicero, Indiana