I have a new Yamaha RXV-2500 (4 months), love the unit EXCEPT I can't seem to get a clean FM signal. It is constantly cutting out while playing. I have a rabbit ears type antenna attached that I got from Radio Shack (bought it for my TV until my cable got installed). I called the dealer, he told me that this unit requires a strong signal, antenna placement is one of the stickiest things their installers face with these units. (??) What frustrates me is the fact that the FM I get on a $200 Sony boom box is fine while this thing is cutting out.
After reading some of the posts on RM Antennas via search I'd like to add to my original post that this is not a weak signal but a dropped signal. While the unit is playing the sound is good, no static or hiss, it just drops the signal 100% (NO sound) for a fraction of a second VERY frequently. Some drops are longer than others (as I sit here listening to it while I post)
I'd second Dale's suggestion about splitting your cable; that's what I've always done with my receiver and have always gotten good FM reception that way.