Paul, you’ve brought up something intriguing and that may appear on iPhones in the next few years. Apple, normally extremely secretive about new developments, has been hinting that it is working on a new technology that would allow texting from locations without cellular service, texting that would use satellites in some new way. Here is a news story about that:

https://9to5mac.com/2022/04/24/gurman-apple-watch-could-feature-satellite-connectivity-in-a-future-model/

I’ve been one of those who’s been skeptical of the idea on Mac sites.

Of course, texting much like that in cellular phone systems is quite possible. Among others, Garmin has been selling InReach devices that do just that for years. They use Iridium low-earth-orbit satellites. InReach to InReach, the system doesn’t even need ties to the Internet. The text can go up via one satellite can come down via another. But even though those devices are small—the smallest is about the size of a pack of cigarettes—there’s not even close to enough small enough to fit the electronics inside an iPhone. Apple is not going to make a clunky, thick iPhone to add a feature that most will rarely, if ever, use. Even more mystifying, Apple seems to believe it could build this into an Apple Watch.

Also, recently I and others mocked the limitations that Apple was attaching to the technology. The texts would need to be few and sent only from locations where there was no cellular service as an alternative. Essentially, it was to be an emergency-only service. Why, I asked, impose those limitations? If it works, it works. Garmin’s InReach devices don’t impose those limitations.

Well, as often happens, just after I say something I realize that I may have gotten it wrong. There is a way to do what Apple is claiming it may soon do, a way that even imposes the same limitations that Apple says will exist with their new mystery technology.

What if the technology that Apple is working on uses these new digital modes to "compensate for much, including poor antennas, low power, and poor location”? That would explain much. It would explain how the technology could be squeezed into an iPhone or even an Apple Watch, talking to a satellite 150 miles up on a fraction of a watt. An iPhone already has the precise timing required via GPS. The iPhone could take care of the signal processing, both send and receive. And the strict limits on use that Apple hints at make sense. The limited number of hams means we can use these digital modes for any purpose we want. But with tens of million of iPhones being sold, the message capacity of any below-noise digital mode would quickly be overwhelmed if used for just any purpose. The use will need to be limited.

Last but not least, Apple has already broken with Intel and is making its own CPU chips. In the near future it plans to break with Qualcomm and make its own 5G cellular chips. At that point it could add the capability for a new satellite, digital, weak-signal mode—a feature that competitors such as Samsung would not have. All that is lacking is the proper technology in low-earth-orbit satellites, and according to the article linked above, that could come vias Globalstar..

Many of you know far more about these weak-signal digital modes than I. The idea is not impossible. I just wonder how feasible it is.

—Mike Perry, WA4MP