Hacker News Reader

Comment by stavros | Hacker News Reader

That's amazing, I'm having trouble believing that a mobile phone's antenna can talk to space, 500km away. Do you know what sort of bandwidth these will have?

View on HN

The bandwidth will be small. I saw 2-5 Mbps for the whole cell covering a city. Devices will be limited to messages, small amounts of data, and voice.

That's still the difference between lost in the mountains and "my coordinates are X, Y".

But it's still a mobile phone transmission power (1W?) and then r^2. Distinguishing that from noise seems mind-boggling.

Really just makes one think what sort of capability military has.

Check out the Orion series of Sigint birds[1]

" The satellites have estimated mass close to 5,200 kg and very large (estimated 100 m diameter) radio reflecting dishes."

[1] https://en.wikipedia.org/wiki/Orion_(satellite)

But just to clarify, because I'm also having a hard time imagining this, an LTE antenna in a cell phone can beam data to a satellite and have it picked up? Even at whatever low kbps? That is insane to me!

Yes. It's been demonstrated a few times.

There are IoT devices that can talk to geostationary satellites, and these are roughly 100 times further up (36000 km vs. 300-1000 for LEO)!

I have one that’s significantly smaller and lighter than a smartphone, antenna and all.

These satellites partially make up for the distance by deploying huge antennas, sometimes augmented by large reflector meshes that can only unfold in space.

Yeah, that's pretty crazy, I guess that's what GPS receivers do, in the end (though at pretty low bandwidths).

Reply on news.ycombinator.com