[KLUG Members] Any sattelite ISP that supports Linux?

[Peter Buxton]

On Wed, Sep 18, 2002 at 12:49:25PM -0400, Adam Williams wrote:

> Right, with a strong emphasis on the "and" in "(from you ***and*** its
> base station, remember)".  So that's a minimum of ~80,000 miles round
> trip.

No, dude! ~45,000!

A geosynchronous orbit has to do deal with the fact that all orbits are
"Great Circle" orbits. That is to say, you must orbit the planet on a
circle of the largest possible diameter. You can orbit the Equator, but
not the Arctic Circle, nor the Tropic of Capricorn. (Well, you can,
Admiral Kirk, but only under powered flight.)

The only possible geosynch orbit on a 'rotating' planet is its equator.
(Non-rotating planets have no geosynch orbits except for LaGrange
points. (Which we will boldly gloss over here.)) Any other Great Circle
would have your satellite bobbing up and down in the sky, north and
south, as the plane of its orbit is offset from the equator. (Go play
with Xearth or Xplanet, Mercator projections, and the sunlight
terminator for why, or watch a Hollywood space flick and watch the sine
wave on the Earth that is the path of the satellite.)

The Space Shuttle's typical orbit is ~180 miles. A geosynch orbit is
~22,241 from the Equator. If you have a little trig, it should be easy
to use your latitude to calculate how much farther it is from you to a
geosynch satellite. From the Poles, it's ~31,048. So that would be a
two-way range of ~44,482-62,096 miles to the satellite if only *one*
satellite is used! They do have multi-hops, but they would be to other
geosynch satellites orbiting Earth on a circle 60,000 miles wide!

> If satellites were such a great bi-directional communication method,
> why are there fleets of submarines used to lay fiber cable across the
> ocean floor? 

Unless Cable & Wireless switched to subs in the last 5 years, they still
use surface cable-laying ships. The hands-down finest easy intro to this
is still Neal _Snow Crash_ Stephenson's _Wired_ article, "Mother Board,
Mother Planet." But yeah, they're still slapping down fiber optic like
there is no tomorrow.

-- 
http://www.killdevil.org/~peter
Rude people, not God, make religion incompatible 
with polite society and good government.