Many people reading this blog never listened regularly to music on AM radio. The generation born after 1970 got its first music fix either from FM or MTV, and therefore has little use for AM, unless they’re looking for talk shows or sports play-by-play. A few AM stations are still playing pop, soul, or country oldies, big-band, or gospel, but nobody who’s making money on AM is doing it with music. And why shouldn’t it be that way? Despite staggering technological advances in broadcasting, the audio fidelity of AM is still terrible compared to FM.
AM stereo was supposed to help. Throughout the 1980s, several manufacturers competed to have their system adopted as the standard, much as TV broadcasters did for color in the early days. It wasn’t until 1993 that the FCC adopted a single system. At that time, I was working at a small station in Iowa, where our crosstown competitor began broadcasting in AM stereo. They promoted it fairly well at first, taking AM stereo equipment into the community to demonstrate it. Their next idea was not so brilliant, however—they began ceaselessly promoting the stereo simulcast of a Whitney Houston concert on HBO. It didn’t occur to them that the vast majority of AM stereo installations were only in cars, which were not generally equipped with HBO. (Car makers had begun installing AM stereo equipment with the 1985 model year.)
It didn’t matter, however—AM stereo was largely a dead letter by then, although the odds are good that your car’s AM receiver can still get it today. Mine does—one day I killed time waiting for an appointment by surfing the dial, and was surprised to find an AM station that lit the little stereo light.
Another problem with AM was the fading of distant signals, particularly at night. It’s got something to do with sky waves versus ground waves, which is also why AM signals travel so far at night, but whatever the reason, you had to live with fading if you were an AM listener (although it was frustrating when it happened in the middle of your favorite song). AM stations were also subject to interference from the whispers and shadows of other signals (and sometimes from the buzz of Mom’s vacuum cleaner downstairs), but you had to accept that, too. After all, it was a long way from their tower to your radio.
The distance was part of what made AM radio seem larger than life. On a typical day in Wisconsin, I could easily hear stations in Chicago, but at night, the stations I heard could be many hundreds of miles away—Detroit, Minneapolis, Philadelphia, New York, New Orleans, San Antonio, Richmond, Winnipeg. And the distance was also metaphorical. Even the AM stations close to home had a distant sound. The DJs didn’t sound like they were in the same room with you, as they can on FM. It was clear that they were someplace else, and it didn’t take long before I wanted to be wherever they were.
In the United States, AM signals are capped at 50,000 watts of power. In the early years of radio, however, there was no such restriction. In the 1930s, WLW in Cincinnati operated at half-a-million watts for a time, so much power that some people could hear it without a radio—almost anything metal would pick it up. (Read more about WLW’s transmitters here.) Even after American stations were limited to 50,000 watts, Mexican stations could operate at higher rates of power, and some did—from 250,000 up to a million. A few Mexican stations close to the border (and in the hands of American owners), known as border blasters, became legendary. Wolfman Jack became famous at XERF, across the border from Del Rio, Texas; XEAK in Tijuana was the first top-40 station heard in southern California; and 150,000-watt XEROK in Juarez, across the border from El Paso, claimed to be the highest-rated station in the United States in 1975.
A couple of years ago, a reader of this blog (whose name I am ashamed to say I’ve forgotten) sent me an aircheck from XEROK, known as X-Rock 80, from August 1976. I found it in a box of CDs last week, and it’s appropriate to dust it off now. As you listen, notice the intensity of the sound—and how even through tiny speakers with crappy fidelity, AM radio could rock.