I just programmed my new NFL remote to my H24. I am using my original RF remote with the analog TV in the bedroom that is mirrored to the receiver in the living room.
There is a small antenna included with it. (Not needed on the H24)
r15, r16, r22, h20 and up hr20 and up is RF capable.. r15 needs antenna, h20 and hr20 need antenna, i forget about the 21 series but the h23 and hr23 and h24 and hr24 DO NOT need antenna..
Will only certain remote models are RF, but the easiest way is to look for the FCC sticker on back of the RF remote, if it doesn't have one its not a RF remote.