Eschatologist wrote:

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Crap maths alert....

The SpaceX satellites are much lower (like 1000km vs 35,000km) and have bandwidth per satellite of ~20Gbps.

My house on a crappy 50Mbps connection typically downloads about 750GB/mo.So that's an average of about 1GB/hour, or 0.002Gbps.

So one satellite can support 10,000 of my households, at best. How many Irish households are beyond fibre?

SpaceX are "planning" to launch 4,425 satellites, so that's 44 million households, or about 177 million people, or about 2% of the earth's population.

OK have some better math. A constellation of 4,500 satellites as you describe there covers 'the earth' but we all know 'the earth' is 2/3 water.

At 1000km we can assume safely enough that

4000 are engaging land to some extent and only 500 are like TOTALLY over a pole or a large ocean with no people (and they have no backhaul in Antartica either but no matter). This is also assuming that we don't have in orbit spares counted in the 4500 and that we do not have EG 25 planes of 200 sats each with 5 spares per plane or whatever the redundancy ratio is in such a constellation. I am assuming that 4000 out of 4500

are beaming at any given time.

The 4000 in actual service are, of course, covering

all of humanity or 8 Billion people by the time this lot launches. This means that every satellite in the constellation of 4000, in effect, is covering

an average of 2,000,000 people at any given time, sometimes more and sometimes less.

The land area of the earth is around 150m sq km while the remaining 300m sq km is water. I assumed, probably wrongly and also with some evident caveats, that the 4000 will therefore be serving 150m sq km or 37500 sq km of land per satellite. The state has a surface area around twice that 37500 sq km of land that but I would assume (probably correctly) that 4 sats are actually covering the state at any one time, in whole or in part, and with most people served by 1 of the 4 at a time on an ascending or descending orbital plane.

This means that the entire population of Ireland have 20gbits x 4 ( Total 80gbits) available to them at most and that only those on edge swathes have a lot available while the 'main' satellite at any given moment is probably covering 3m people...this is simply because satellites move but houses don't.

20 gbits thruput once spread across 2 million people (the National Broadband plan is to service 1.4 million people) is fuck all in mathematical terms.

80 gbits thruput off 4 birds is fuck all in mathematical terms too.

My boreen in Galway, alone,

has 2.5gbits already, a single GPON standard PON. If we need an upgrade we go to NG-PON2 or XG-PON in the next decade and the same boreen will be then be sharing 40 or possibly 100m GIGABITS.

A 4G cell with fibre backhaul (that very few of them owing to wayleave issues with commonages and farmers who own teh land around these high sites I can assure you) could handle 1gbit per sector and with 3 sectors in use in a typical cell that could be 3gbits.

Most 4g cells actually have 155-600 mbits of backhaul for all users on STM1 or STM4 wireless links. That 4g cell covers, typically, a parish or so. 4G (or 5G) would have say 600 mbits at best for 1000 households or 3,000 people. Rare ones have 3gbits or 1gbit per sector. 10 gibit feeds to rural cells are almost unheard of even if the local telephone exchange 2 miles away has 10gbit product available.

All of this 4g/5g tech cannot compete with my GPON fibre that I only share with a few neighbours, thank you for reading.

I hope that is enough math for you.