The Slow and (Not So) Painful Death of AM Radio

We take it for granted now, but wireless communications have existed for over 100 years.

The first licensed commercial radio station in North America was CFCF in Montréal in 1919. The first in the United States in 1920, KDKA in Pittsburgh, PA.

In those days, the need for a high-quality broadcast was not necessary and nobody thought about the future of broadcasting. Programming was simple, consisting mostly of radio dramas and comedies with occasional live bands.

The broadcast signal was amplitude-modulated. That means that the wave level was varied and demodulated at the receiving end. The problem with that is that everything that produces an electromagnetic field also produces an amplitude-modulated wave. It was not so much of a problem in the early 20th century since there were not a lot of devices that produced AM waves, There were some naturally occurring events that caused a problem, such as lightning, but it was rare and tolerated since there was nothing that could be done about it.

As the need for better technology grew, a new form of audio broadcasting was invented. First used for military communications and later for broadcasting, the frequency-modulated signal was being used. Some say that this was the first nail in the coffin for AM.

FM could produce a better quality signal because it offered a wider bandwidth. Bandwidth is the amount of room a signal takes up within the spectrum. In North America, the bandwidth for an FM station is 200 kHz but for AM it is only 10 kHz. That means there is less room for signal output for AM than for FM and is the reason FM sounds better.

However, AM Broadcasting stood a firm ground against its rival FM for many years and well into the 1980s. Music was common on AM then and to keep up with FM, a new technology was created for the AM broadcasters.

Stereo. FM had already been broadcasting in stereo for many years prior, but this was a first for AM. It was the mid-80s and it was predicted to be a major change for broadcasters. \however, it turned out to be a flop. The first problem was that AM Stereo receivers were very expensive. Much more so than an equivalent FM Stereo radio. Another was that there was no standardized technology. There were several different forms of AMStereo including, Motorola C-QUAM, Harris, Magnavox, and Khan-Hazeltine. None were compatible, so if your (expensive) AM Stereo receiver only could process C-QUAM, that’s all you would get.

Eventually, radios were manufactured for compatibility with all systems, but it was too little, too late. It was the late 80s, and by that time FM began to slip ahead in the radio broadcasting arena. Another nail in the coffin for AM.

Although, AM had always had an advantage over its rival. Coverage. An AM signal can travel a lot farther than FM because of the way the signal is transmitted. AM waves travel at an angle from the transmitting tower and bounce off of the atmosphere. AN FM signal is broadcast horizontally from the antenna and so the receiving antenna has to be within line-of-sight of the transmitter. Although FM has been known to cover great distances as well but not nearly as far.

There used to be a hobby called DXing where people would try to receive stations from great distances. Then they would send a signal quality report to the station and the station, in return, would send the listener a QSL card that listed the station call and city. During a major blackout in 2003 when no local stations were available, the farthest AM I was able to receive in Southern Ontario was KCCT 1150 from Corpus Christi, TX with a signal quality of ‘5’, the highest. The farthest FM I was ever able to receive was WNCD “The Wolf” 93.3 from Youngstown, OH, with signal quality ‘4’. I can also sometimes get WCBS 880 from New York with a quality of ‘4’.

However, despite the range of AM broadcasts, FM continued to dominate. AM stations were abandoning music formats for all-talk shows and even all news, Another nail in the coffin.

Problems began to worsen for Am as Smart Home devices became popular. Before I mentioned how electromagnetic fields interrupt AM radio. Smart Home devices emit a wide-band EMF that sometimes completely jams AM radio but does not affect FM. In most cases, one can only receive FM in the home due to this reason. Another nail, but that's not all. Some automotive manufacturers are removing their car radios from receiving AM.

In AM dead yet?

It depends on who you ask. Companies who operate AM stations and those who advertise on them feel that AM is dead. It is, in the traditional sense. However, we are forgetting that there are now other ways to receive AM radio other than with an antenna. Ironically, the Smart Home that blocks AM signals can play AM stations. One Am in my area just switched back to a music format and it doing quite well thanks to Internet streaming.

Am radio and radio in general can be brought back into the limelight but the owners and advertisers have to change their ways of thinking as to how radio is broadcast.