Flying Too Close to the Sun

Does anyone remember the early(ish) days of mobile in the U.S.? Not the really early days of analog service with per minute rates that cost you more than a meal every time you looked in its general direction. No, I’m thinking more the early days of GSM and in particular Nextel. And not for a particularly good reason: I’m not here to reminisce about push-to-talk (“where YOU at?”). 

Rather, I’m thinking about the freaky interference the service caused anytime you stepped too close to any consumer electronics that had a speaker attached. If you wanted some entertainment, you could walk through a consumer electronics store, dialing numbers on your rather clunky phone and listening to the dial ring reverberate around you through distorted, tortured TVs.

And it wasn’t just Nextel: GSM-based service (not that there was a lot of that around those days) was just as… well… interesting. But only in the U.S. Elsewhere in the world, it all seemed to work just fine, with the phone and other electronics in, if not harmony with each other, then at least by totally ignoring one another.

Because it really had nothing to do with the technology… and everything to do with the frequency of spectrum it was running on. Nextel was only particularly annoying near other consumer electronics because it used an innovative patchwork of spectrum that was never designed for cellular service: thin slivers of two-way radio frequencies bonded together into a Franken-mobile solution that worked rather well. But other mobile solutions could also have benefited from a little more shielding, with a larger gap between the frequencies used and those that interfere with other electronic devices.

And, with that in mind, there was a reason why the U.S. banned the use of mobile phones on planes while other countries did not: U.S. phones skirted just a little bit closer to the sun, as it were, using spectrum that was a little closer to other use cases, rather than leaving a larger, dead zone spectrum barrier.

Which brings us to the most recent spectrum kerfuffle with 5G. First 5G was accused of mysteriously – and falsely I should add – of killing birds, and now it apparently has the power to down planes almost at will.

The problem is, much as none of us want to believe this one, there may be some truth to it. And to be clear, if there is, then the fault lies with the government that sold the spectrum bands, not with any carrier that is trying to use the spectrum they purchased. Unlike in other countries, where there is a larger buffer between the top of the C-band spectrum range and the frequencies used by aircraft altimeters, in the U.S., that gap is smaller, which is why other countries do not seem to have the same issue with 5G and aircraft. But in the U.S., the narrower gap has caused interference concerns, particularly with Boeing 777 planes apparently, and particularly near airports when the plane is (obviously) closer to the ground and requiring the use of altimeters, especially in poor weather conditions.

Is it real? The carriers are pretty convinced that there is no merit to it and are doing all that they can to mitigate the issue, delaying the deployment of these frequencies near airports. The airlines are clearly more cautious, cancelling flights that use “at risk” technology. After all, there’s nothing quite as bad for business as a downed plane. Many of the industry pundits are scoffing at the issue, and hopefully they are right, but I suspect many of them weren’t around in the Nextel days. In those days, after a few drinks, many carrier employees debated the merits of spectrum interference on planes and while they never came right out and said there may have been an issue, they pretty much all admitted to being the first to turn their phones off when they got on a plane. So, while the debate is hopefully discussed and resolved, I think I may try to pick my flights more carefully.


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