Dave Kolesar sees digital transmission as the salvation of the AM band (Dec. 4, 2019 issue), but AM problems are more social than technical. There are perhaps 20 times as many AM stations as there were in the 1950s, but far fewer listeners. Receivers haven’t improved; in fact on the whole they have got worse. Much of the problem is sheer overcrowding.
The one major benefit of AM, where AM shines over all other possible delivery methods, is long-distance reception over skip and the ability to deal with severe multipath on rugged terrain. Any digital system for AM broadcast that cannot contend with skip reception or degrades reception in mountainous areas is destroying the one advantage that AM has.
Yes, it’s possible that IBOC MA3 is a great improvement over MA1, in that MA1 not only was inaudible over skip but made adjacent-channel stations unlistenable. MA3 is much less likely to destroy reception of distant stations, but the digital carrier is still destroyed by Faraday rotation.
If your station is not audible on skip, and you’re not in a mountainous area where FM is problematic, you probably shouldn’t be on the AM band. I know a lot of AM stations realize this and would like to move to the FM band but cannot. The FM band is too crowded too.
But we need to sit down and face the real truth that there are too many stations on the AM band broadcasting junk programming that people are not actively listening to. It is time for some weeding out, so that stations that can take advantage of the actual advantages of AM are able to do so.
The NAB doesn’t want to talk about this. The FCC doesn’t want to talk about this. All anybody wants to do is promote technical solutions to the wrong problem.
I would be strongly in favor of digital systems that were able to cope with skip transmission, such as DRM. But there’s an easy way to dramatically improve listenability of the band, it’s just that nobody wants to talk about it.