The author of this commentary is a broadcast technical author in Australia, which still uses AM radio extensively. He has spent a lifetime in training technicians. He writes here in response to Larry Langford’s recent commentary “Time to Come Clean on AM Quality.”
Larry Langford’s brief history should have noted that AM was invented in 1901 and the first permanent broadcasts were 110 years ago. By comparison, cellphone companies switch off their oldest technology every eight years, leaving an operating life of 16 years.
The AM channels are spaced 10 kHz apart with a high-frequency audio limit of 10 kHz, so the transmission channels overlap the adjacent channels. This may have been fine in the past due to the quality of audio equipment, but now with audio processors there’s plenty of energy in the 5–10 kHz range to cause more audible interference to broadcasters in the…
