It matters a great deal. While AM quality sucks, the modulation is more robust than FM and the AM band (specifically as opposed to the modulation) can go much further.
I've been exploring the AM dial since this issue first arose a year or two ago. So far, the furthest transmission I've knowingly received was a station in Chicago while I was in NW Connecticut. I've also heard of people in the NE US receiving transmissions from Central America and Europe, especially at night (the sun causes some amount of interference).
Ya, AM. The 1Mhz band is insanely long range (under the right conditions, blah blah).
You may protest that you can FM at 1 Mhz and get the range boost on a much nicer sounding signal but:
- FM isnt as efficient as AM and 1 Mhz isnt a lot of space
- FM "locks in" to a station, partially what makes it sound so good. On AM you hear everything and its "up to you" to figure it out; meaning the intended signal is there and you might be able to squeeze meaning out of it (since you know a lot about it). On FM if the receiver cant "lock in" or locks into another station you cant receive any information.
That last point is also why morse code is so reliable - a human operator can very easily distinguish a sine in noise
AM band frequencies has greater range under the right ionospheric conditions.
In the event of needing to communicate in an emergency you must assume that the right ionospheric conditions will not be present and that you are limited to line of sight.
The point is that anything besides line of sight is unpredictable, so the ability for AM to sometimes reach around the world is irrelevant if you need to know how many people it will reach, which is, more or less the same as FM.
In other words: you really don't need the ability to sometimes unreliably broadcast icy road conditions, or a tornado alert, to someone three states away.
