I do a fair amount of "DX listening" and i note that when driving, a stronger FM broadcaster will "pop in" even if for just a couple minutes and then gone. On 2M hamband the strongest station wins, with just a growl heard underneath. On MW AM band, i can so often hear audio from 2 stations, maybe more, on same channel. The freq accuracy of the AM transmitters is such that there's no beat note at all unless very rarely one of the co channels might be overseas. So on AM to separate them you either need a directional antenna, or just wait and hope a station comes way uo in strength for s spell.