Little differance.
Have never had a problem with reception with AM or FM, old or new. With the square wave signal, wonder if it AM/FM is even an adequate term? I know some have stated that technically there is no reason FM would be better than AM. AM doesn't need to be dual conversion to be narrow band, but I don't think FM has to be either????? Need some experts here? Have a Hitec 3 channel that is AM. No problems with it.