You do need a time source though. GPS is generally used for that but it doesn't need to be extremely accurate with FT-8 like with some other protocols.

I would imagine using it for a regular "I'm ok" message for the home front in such a situation using pre-arranged contents.

I tried it while staying in a high rise hotel and the experience was great. Instant acknowledgement and super reliable communication

Relevant, Chinese domestic media reporting on China's own perspective:

https://www.scmp.com/news/china/science/article/3178939/chin... ("China military must be able to destroy Elon Musk’s Starlink satellites if they threaten national security: scientists" (2022))

> "Researchers call for development of anti-satellite capabilities including ability to track, monitor and disable each craft / The Starlink platform with its thousands of satellites is believed to be indestructible"

"Easy to bring down" vs. "believed to be indestructible"—some tension there!

And I doubt China would want to make LEO impossible to move through anyway. It’d affect China badly as well

Not really, because you'd be using a frequency that passes through clouds. A snow storm or hail is impenetrable, and there are weather events that cause a 1-2 second blackout, as well as cause refraction (which is mostly a challenge in reaiming the beam fast enough to compensate), but anything in the air is fine. Clouds, mist, ... But is aiming at a 1 arcsecond target moving across the sky at at least 1 degree per second from a normal (ie. moving) building really doable with "standard hobbyist telescope mounts" ?

I know 5 years ago we were still doing this with lasers on rockets toward planes, because planes can just keep their angle to a rocket essentially constant. I know there's experiments doing direct laser to satellite, no idea how well that works.

Though India doesn't have a great firewall so it's much less of an issue for foreigners visiting there.

So using DNS hosted outside won’t matter, because the destination Chinese IP will get blocked. Or if using outside hosting, it won’t matter, because anyone in China trying to access it will get blocked. Or anyone trying to publish anything to it the CCP doesn’t like. Presumably also with some follow up in-person ‘check-ins’.

The GFW is a pretty massive and actually impressively effective piece of technology, even if we don’t agree with it’s purpose.

If you get a green card and leave the us for any amount of time, on return the border agent makes a determination on the spot if you intended to live abroad.

Less than six months is simply less suspicious than more.

Besides that, when negotiating a secure connection through unencrypted channels you typically use Diffe-Hillman to establish the encryption keys. As far as I'm aware, this method cannot be broken. Both nodes compute their own private encryption key and do math to create unencrypted data that must be verified by the other node's key. Even if you had full control of the data stream, you can't determine those private keys and cannot break into the encrypted connection that follows.

Also VPNs are typically UDP, but there's no hard requirement as far as I know.