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Second BMW Model Lacks AM

Electric motor interference to AM reception sparks action

A second electric BMW model leaves AM out of the dash.

A high-end sports car from BMW now available here, the i8, also leaves AM out of the tuner.

We noted earlier the i3, at a much lower price point, has an FM-only tuner. HD Radio is standard in both the i3 and i8. 

Press reports indicate the automaker made the decision after experiencing interference to the AM portion of the radio from the electric motor in other models. I’ve reached out to BMW for comment.

NAB recently asked the automaker to reconsider and offered help to solve the engineering issues; the trade lobby tells me it hasn’t heard back yet.

The automaker recently delivered the plug-in hybrid BMW i8 sport car to the first U.S. owners. The automaker touts the model’s low fuel consumption (76 MPGe) and emissions output. The base listed price is $135,700.

Other automakers like Ford and Toyota have electric vehicles but still manage to include AM in their in-dash tuners.

Engineers have suggested to me that the European-based automaker may have chosen to optimize the i3 and i8 for other things their electric car buyers may value more than AM reception, like longer battery life. That’s important to electric vehicle owners, who need to plan their trips ahead based on battery range.

BMW i8

Also, vehicle design involves all kinds of trade-offs, like vehicle weight and size, and, of course, price. Plus, electric motors are prone to causing AM interference. “When you design for AM in a vehicle you need to address more than the radio and the (really long) antenna,” was the consensus of a couple of broadcast engineers.

“Getting CPU and LED display driver noise out of an AM radio in close proximity is really tough,” says one engineer whose company has both AM and FM facilities. Some automakers “simply see a lot more long-term value in the Wi-Fi and WiMax digital content delivery to vehicles than fighting the AM battle.”

On the concept of AM’s fate in the dash in general, Bryan Broadcasting’s Ben Downs tells me: “If AM is removed from a vehicle, the manufacturer is taking away an option for the driver; an option the driver probably expects to find in the dashboard.”

While broadcasters worry about the long-term fate of AM in the dash, the news may not be all gloom and doom.

Engineers are usually interested in tackling problems and unsolicited, the Southern California Broadcasters Association is tapping into that spirit. SCBA President Thom Callahan is working to form an engineering committee to help BMW with the issue of its electric motors causing interference to AM in-dash reception by forming a group with several kinds of engineers.

If successful, what they discover may help other automakers with electric motors as well.