Electric cars may be energy efficient Earth-saving futuremobiles, but their rise could also have a strange unintended consequence: killing off the oldest form of radio.
Two popular electric cars, the BMW i3 and Tesla Model X, are ditching terrestrial AM radio because electromagnetic noise from the electric motor interferes with the broadcast reception, causing static, as the blog Music 3.0 recently pointed out.
Electronics have always been a source of AM radio static, and electric motors are no exception. EVs are powered by a rechargeable battery, electric motor, and a frequency converter that controls how much power the car's electrical motors put out by turning voltage on and off thousands of times a second, basically chopping up energy. This process causes electromagnetic interference that gets picked up by the radio.
AM radio has always been more susceptible to static than its partner on the dial. "AM" stands for amplitude modulation, which means the height of the radio waves are varied over time to encode the information, versus "FM," frequency modulation, which varies their speed. Since amplitude, not frequency, is affected by electrical noise emitted by gadgets like smartphones, TVs, computers, even vacuum cleaners and hairdryers, AM signals are prone to distortion and crackling.
That crackle apparently just doesn't fly with luxury auto brands. BMW spokesperson Rebecca Kiehne told me, "Electric motors cause interference on AM which is why BMW decided to remove this option. While it could be offered, BMW's performance standards are very high and we don't offer a product that meets less than those high standards."
But while BMW disabled AM radio in the i3 because the company was worried customers would complain about the poor sound quality, some customers have instead taken to complaining about the lack of AM radio. Consumers took to forums to bemoan the omission, a few even saying they wouldn't buy an i3 without it. One BMW owner commented, "I plan to drag out my portable AM radio and leave it in the car." Some owners are hacking the car to get AM radio back.
Meanwhile, the new Tesla Model X also dropped terrestrial AM radio from its infotainment dashboard—a change from the Model S. Instead, you can get most AM stations via internet radio if you go menu diving through TuneIn, a service that aggregates internet radio and traditional AM/FM stations and is the standard radio option in Tesla cars.
"AM radio stations are accessible through our internet radio service in Model X. Because AM audio quality can be very poor, we offer internet radio to give our customers considerably better sound quality and reception coverage," a Tesla spokesperson told me over email. Apparently, finding the stations isn't always easy though; there's a Tesla forum devoted to figuring out how to locate AM stations on the Model X.
At this point you may be asking, who cares? Isn't AM radio a dinosaur technology with one leg in the grave? Does anyone even listen to it? The answer is yes: about 3 million people listen to it every day, and five of the ten most popular radio stations in the US are AM radio. "This narrative that somehow AM radio is dying is silly," Dennis Wharton, communications executive at the National Association of Broadcasters, told me.
Despite the higher sound quality of the FM band and the ascent of satellite and internet radio, the medium of FDR's fireside chats and Rush Limbaugh is still cemented in American culture. AM signals can travel further distances, making it popular for talk radio and local programs like weather and traffic reports or emergency response information. It's also more affordable to get on, so is home to lots of niche stations like foreign language radio, college radio, or religious programs. "It's a haven for minority radio stations as well—particularly Latino and Hispanic radio has moved a lot to AM radio in recent years," said Wharton. Not to mention some major sports franchises still broadcast games, sometimes exclusively, on legacy AM stations that have been around forever and have fiercely loyal listeners.
The National Association of Broadcasters (NAB) is asking BMW to reconsider its decision to drop AM radio, and NAB's California branch has teamed up with engineers to devise a solutions to the static problem. A group of engineers in Germany are also working on a prototype for minimizing interference by shielding the engine's cabling and insulating the motor, at a price point that's affordable for automakers.
Cars and radio have always been inextricably linked: about 90 percent of people listen to traditional radio over the airwaves (more than use the internet), and 40 percent of that listening happens in the car. So it's worth raising an eyebrow if electric cars are zooming toward the future and leaving a historical technology behind.