[Retric]

The only way to add one satellite over NYC on average is to also add several satellites over the ocean and other low density parts of the earth. If you want low latency individual satellites must be in LEO which means they spend most of their time over water and low density bits of land.

Which gets back to my original point where increasing the maximum density inherently reduces the average utilization of each satellite. There simply aren’t enough people living in Iowa etc to balance the east coast.

[CorrectHorseBat]

Sure, but my point was that there's a maximum density you can get which won't be enough for NYC or even a much less dense city.

[Retric]

The current network can handle 1 home per square km on average but averages over a very large area. So ~2,000 as many satellites and you can handle NYC’s population.

It’s actually less than you expect because you can make use of satellites a hundred miles out to the sea, over the Hudson River, and even suburbs. And that’s before considering how few people would pick Starlink when they can use cheap fiber.

[CorrectHorseBat]

Well no, that's my whole point. Because you're sharing the medium you'll get interference if multiple satellites service the same area.

>And that’s before considering how few people would pick Starlink when they can use cheap fiber.

Obviously we're talking about how dense an area Startlink can service on its own.

[Retric]

> Because you're sharing the medium you'll get interference if multiple satellites service the same area

I’m going to simplify because you seem to misunderstand what’s going on.

Your eyes allow you to see a clear image of your surroundings because photons come from even slightly different angles aren’t interfering with each other. Starlink uses a phased array antenna to achieve a similar effect where satellites in different locations broadcasting on the same frequency can be clearly distinguished by two base stations physically next to each other. And similarly two different satellites can receive clear signals when two Starlink antennas are broadcasting when physically next to each other at the same instant.

There’s physical limits and the phased array antenna in use are much worse than theoretically possible. But, the technology they are currently using really does scale vastly beyond what’s economical viable.

[CorrectHorseBat]

I'm not at all misunderstanding what's going on, I know what phased array antennas are. It's not really like our eyes, we cannot perceive phase differences in light. A phased array is (at theoretically best) like a satellite dish which can move without actually having to physically move.

>Starlink uses a phased array antenna to achieve a similar effect where satellites in different locations broadcasting on the same frequency can be clearly distinguished by two base stations physically next to each other

If by next to each other you mean several km apart, yes. edit: Ok, I didn't think of that, if the satellites are far away from each other it'll work indeed since it's both the sender and receiver which have directivity. That indeed would make it scale better.

Sure the technology can be improved, but there's only so much you can do at several hundreds of km distance and the sizes of antennas you have. Especially with mobile phones which are small and power limited I really don't see how it could work in anything but very low density areas.

[Retric]

Starlink cellphone connection operates very differently. It’s a different system on different frequencies with different limitations, and it doesn’t scale well.

> If by next to each other you mean several km apart, yes

By close I mean inches. Phased array’s aren’t great at directionality, but both the satellite and the receiver are using them which makes a real difference because the satellites are in different locations even if the receivers aren’t.

At the limit satellite A has a few spot beams one is aimed at say one World Trade Center which also covers several blocks around it. It’s 5 miles from satellite B which isn’t aiming at that location, but another satellite say G that’s 20km away is.

Hypothetically 2 ground stations X1 and X2 are 1 foot apart on the roof of one trade center. X1 can get a signal from satellite A at 25 DB higher than the signal from satellites G because there’s a few degree difference in incoming angle and 50DB higher than from B which is both a degree off and aiming elsewhere.

Similarly A receives a single from X1 that’s 25 DB higher than from X2 because their signals are aiming in different directions. (DB numbers were picked from a hat but I had a several variables already.)

The real world isn’t that simple, and there’s no way in hell their software is setup for that many satellites but phased array antenna on both side makes a big difference here.