How electric vehicles could spell death for AM Radio

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How electric vehicles could spell death for AM Radio

Postby radiofan » Sun Jul 31, 2022 9:54 am

How electric vehicles could spell death for the oldest form of radio broadcasting
Alan Cross - 3h ago

My neighbourhood is lousy with electric vehicles: all flavours of Teslas, scattered Volts and Bolts, a selection of Hyundais and KIAs, a couple of Nissan Leafs (Leaves?) along with some Taycans, at two Polestars that I've seen, and at least one Lucid. They're all loaded with so much fabulous spaceship tech that the mind boggles at what our driving experiences will be in the next 10 years.

However, one piece of tech is missing from many of them: a good old-fashioned AM radio, a feature that goes back almost a hundred years.

As far as people can tell, Kelley's Motors in New South Wales, Australia, was the first to jam a new-fangled aftermarket radio into a car back in 1924. But it was the Galvin brothers and their new company, Motorola, that created the ancestor of all car infotainment units when they fitted a six vacuum-tube AM radio in a Ford Model A in June 1930. They overcame plenty of engineering problems, including where to put the giant high-voltage batteries (under the passenger seat), how to house the six vacuum tubes (in a big wooden case), placement of the antenna (on the roof), and most importantly, how to eliminate static caused by the electrical activity of the engine.

AM signals are easily disrupted by electrical activity. Overhead powerlines, lightning, external electric motors, and even the running of an automobile engine are enough to cause crashing static, buzzing, and fade-outs. The Galvins' solution was to fit the spark plugs of their Model A with a "suppressor" so that the firing sequence of the cylinders no longer interfered with the radio. Tuning the engine down like this actually hurt performance, but at least motorists got to listen to programming that was relatively static-free.

Eventually, the Galvins figured out other ways around the static problem, and suppressors were eliminated. But environmental electrical interference remained, and this spurred the development of static-free FM radio. (That's another story entirely.)

Ninety years later, the AM static problem is back. And it's bad.

Today's electric vehicles are powered by motors that generate electromagnetic fields that happen to operate in the same frequencies as AM radio signals. The result is a war between these wavelengths. The more powerful these motors get, the more adept they are at cancelling out AM signals. It's can make for annoying listening. Other bits of tech, including speed controllers and some of the other electron-power magic inside these cars, also cause havoc with frequencies between 530 and 1700 kHz, which is where AM radio lives.

While there are EVs that offer AM radio as part of their infotainment systems, owners are warned upfront by the manufacturer about the same kind of static, buzzing, distortion, and fade-out issues the Galvin brothers struggled with back in 1930.

Thanks to the physical properties of the FM band, those stations are unaffected by the electromagnetic fields generated by their vehicles. So is satellite radio. What can be done about AM radio then?

Read the full story at: ... 24e9e49563
Those who danced were thought to be quite insane by those who couldn't hear the music.
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Re: How electric vehicles could spell death for AM Radio

Postby RationalKeith » Sun Jul 31, 2022 12:12 pm

The linked article on 'magic' of am radio is a good read especially on range of am signals.

WABC 770 out of NYC could be heard in Europe some nights, thanks to a powerful TX into 5/8 wave antenna grounded in a salty marsh.

In the Peace in the 50s my father could receive a US west coast station, IIRC 'Call of the North' probably from San Francisco. External antenna a few hundred feet long at most.

And CKWX pattern oriented N-S, I received it in Sand Point OR in summer.

And still useful on the prairies, I appreciated CFR66 playing oldies as I drove north-south through Alberta a few decades ago.

While people southeast of LA complain about about not receiving a radio station from LA, directional antenna to protect a station down their direction.

As for interference, one source decades ago was floor-standing lamps pointed upward, hot bulbs, I forget the technology though of course quality helps.
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Re: How electric vehicles could spell death for AM Radio

Postby erratic » Mon Nov 21, 2022 9:14 pm

It should be retired. Maybe in 15 to 30 years FM analogue radio will be retired.
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