Home cinema - Broadband internet via Sky D

This seems to explain it a bit

Q: Why is the latency so high?
A: The way a satellite stays in orbit, without using any type of engine or
rocket to correct its orbit, is to gain a balance between gravity and
centrifugal force. The closer to earth, the greater the gravity pulling the
bird toward earth. The faster it moves the greater the force pulling it away
from the earth. It turns out that there is a spot, about 22,300 miles above
the equator, where the speed an object must travel to gain equilibrium
against gravity is exactly the same as the speed the earth is turning. By
placing a satellite in this spot, its relative position above the earth
stays constant. Satellites used for broadband internet and TV must stay in
one place in the sky so that you can point your dish in one spot and get the
signal. The only other alternative would be to have a constellation of
satellites in a lower orbit, that would rise and fall like the sun and
stars. There would need to be enough of these flying that there was always
one overhead, which requires a lot of satellites, a lot of infrastructure,
and therefore a lot of money.

In the case of a two-way satellite system, when you request something by
clicking on a link, or any other way, that message travels 44,600 miles just
to get to the NOC. The stuff coming back to you must travel the reverse
route, so the round trip is 89,200 miles. The speed of light is 186,000
miles per second in a VACUUM, slower through the atmosphere. But even if you
assumed 186,000 mps then the total time taken in space travel is about
480ms. Given the atmosphere problem, it is actually more like 500ms. Add to
that the terrestrial internet latency, which should be about 100ms. Also you
can add delays through transponders, gateways, proxies, etc.

http://www.sisp.net/broadband/satellite.htm

Two-way satellite has higher latency than one-way. But even one-way
satellite will spend about 240ms simply travelling to the satellite and
back.
Its just a case where the speed of light becomes a limiting factor.
If only there were something faster.

"Darren Wilkinson" wrote in message
...

"Peter G Sheppard" wrote in message
...
Sat broadband has been around for some time. Very good for downloads
but
not
very usefull if you require fast uploads as you use the phone for
that.
Sat broadband has been around for some time. Very good for downloads
but
not
very usefull if you require fast uploads as you use the phone for
that.

Not got at all for playing games either. Because the signal has to go
into
space and back, this takes time, hence why your pings will be around
600ms
or more.

I thought that that was because data had to go through the dialup isp then
the satellite isp then to space.

Surely the internet is mostly satelite based anyway?