| Some reasons most relevant to a lot of HN discussions: AM is the "child's first electronics kit from Radio Shack" science experiment. "Amplitude Modulation" is a fancy way of saying that it encodes sound mostly the way that sound waves themselves do: louder sounds get more amplitude on the radio wave. AM radio waves are just about the only part of the radio dial where the radio wave looks almost even reasonably similar to the sound wave it encodes. The number of electronics to pick up an AM signal and pass it to a speaker (to build a "radio") are about as minimal as it gets and many generations of children did it as introductions to early electronics hacking. AM Radio is the radio that you could conceivably MacGuyver a radio using common household items if you had to in a pinch. AM Radio is the radio that you could possibly even, if push came to shove, MacGuyver a transmitter for it and expect people (in a short distance at least, unless you've got a lot of power or lucky weather) to be able to hear it. Some of the laments over the loss of AM radio are a realization at how much the "floor" of electronics science likely rises. Companies want to fill the bandwidth with more digitally encoded signals, signals that need microchips and firmware and software to encode or process. Teaching electronics to children starts to feel harder and more complicated. Electronics starts to feel all the more like the realm of wizards and elite with money and special hacking tools and less something the common person can understand or "touch" with a cheap kit from a supply store just around the corner (or a YouTube video, some electronic junk, and a potato). A lot of the calls that if AM is to be shutdown more of the bandwidth should be made available to amateur radio come directly from this idea of preserving at least some of the low floor as a sandbox and play space. At the end of the day AM radio is an extremely inefficient use of that available bandwidth and it probably does make sense "for progress" to use more of it more efficiently than before. Relatedly, I think that's part of the sad answer to SETI's search against the Fermi Paradox across the sky: it makes a lot of sense to look for natural appearing signals in the sky in the decades where we are blasting human language looking signals at high power in AM radio bands, but it looks like in geological time (much less cosmological time) that period in our "tech tree" was likely ever so much a short glitch before more efficient, more strangely encoded, more noise-looking, more generally encrypted radio communications replaced them. |