On Tue, 10 Jan 2006, Mark wrote:
monitors (leaving to the satellite and the return from the satellite) That
delay would apply that to voice packets both coming and going, and I really
dont know how anyone could carry on a normal phone conversation under those
circumstances..
I guess I should have qualified my entire question. It was late and I was
half-asleep.
I work for a satellite company and we already have uplink facilities and
space segments on several satellites (Including Intelsat 701, that can see
out into Africa and parts of the Middle East from our uplink on the US
East Coast). I'm trying to get a feel for the market to see if its worth
our time pursuing clients and customers in those areas for voip
termination.
We have numerous clients on our domestic links that run voip to their
mobile satellite trucks/trailers with 500-600ms latencies without a
problem, so I'm not worried about that. As long as the latency stays
consistent, there's no problem with voice quality.
Of course you could make your own calculations however the distance of a
geosynchronous satellite is 27,300 (possibly 23,700 as I do not recall
exactly) miles above the equator, and factoring the speed of light. Keep in
mind that the further you are from the equator that distance greatly
increases and the Earth is also curved. There is sometimes additional latency
introduced at the satellite.
Right. Slant range and all that. Cursed speed of light. Curse you,
Einstein!
There are low earth orbit satellites such as Iridium. In fact I once made an
Iridium phone call, and the latency was barely more than an international
long distance call.. The advantage of low earth orbit satellites is that the
latency is greatly reduced, as the distance is less.
Irridium is damn expensive though. Almost $2 a minute.
I know that Sprint several years back started a low earth orbit internet and
phone service. It was abandoned only a short time later as I recall. I think
it is about time that the tecnology gets revisited.
Bringing lower latency internet to the world via low earth orbit satellites
would be a potentially huge global market. Low earth orbit satellites circle
the globe, so once the sattellites are in place, serving Africa is no
different from serving the USA. Geosyncronous or Geostationary satellites
remain in the same place relative to the earth, and maintain a higher orbit.
There's people like Irridium and Globalstar shooting at the LEO market,
but then there's Hughes aiming at hand-held terminals pointing at
high-power/high-sensitivity geosync birds.
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