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With Geosynch satellites that adds up to roughly 45 milliseconds at a minimum for the signal to get from the base station to the satellite and back down to you.

Your math is wrong. It's 240ms round trip straight-on from the equator, directly below the bird, up to 280ms with both ends at extreme angles. (Damn, I thought it was 250-ish each way, not round trip.) GEO is around 35,000 km, or 70,000km round trip, and the speed of light is about 300,000kps. So that's 7km divided by 30km/sec, or around 233ms, which is pretty close for rounded numbers.

This is exactly why LEO is the holy grail for satellite internet: latency. The downside is they keep moving around and you need a lot of them. Iridium uses 65-70 satellites, but with low, analog bandwidth. Iridium is at 781km, so SpaceX-net will be higher, so a little more delay, but that should improve the view angle a little bit.

SETI would not be able to pick up our communication from 1ly. so..

http://www.satsig.net/seticalc...

http://stason.org/TULARC/scien...

It should be apparent then from these results that the detection of AM
radio, FM radio, or TV pictures much beyond the orbit of Pluto will be
extremely difficult even for an Arecibo-like 305 meter diameter radio
telescope! Even a 3000 meter diameter radio telescope could not
detect the "I Love Lucy" TV show (re-runs) at a distance of 0.01
Light-Years!

It is only the narrowband high intensity emissions from Earth
(narrowband radar generally) that will be detectable at significant
ranges (greater than 1 LY). Perhaps they'll show up very much like
the narrowband, short duration, and non-repeating, signals observed by
our SETI telescopes. Perhaps we should document all these
"non-repeating" detections very carefully to see if any long term
spatial detection patterns show up.

but who knows, maybe others are trying to send signals through their big horns too,

http://en.wikipedia.org/wiki/W...

there is some math involved.

Behind the scenes, yes, but in reality, no. To set up a dish, you get yourself a compass (most smartphones have this built in) and a protractor. Then go to a site like http://www.satsig.net/maps/sat... or your providers site, put in your zip code and point. Turn the TV where you can see or hear it, and start moving it around til the signal comes in clear.

And our resolution sucks. The closest star is only a few pixels wide. We're going to need bigger telescopes to see *anything* directly. Unless something is aiming a signal directly at us, we wouldn't receive it.

Practical example (using default values here) - a 3-meter antenna transmitting at 100,000 watts can only be detected at a range of 1.8 light years. Let's say we used 10MW and transmitted from Arecibo... the detectable range would be 1805 light years. It would only take about a 30kW transmitter using that dish to send a directed signal to a range of 100 light years.

Interstellar communication takes specialized transmitters and receivers. Are we sending anything to those Kepler targets or do all beings take a listen-first approach?

13,000 you say?

While it's true that there are more than 360 of them up there, that's because they're on different frequencies, and there are a few half-angles in the mix (you need a tighter/more expensive beam). Remember that it's not just interference on your part that you need to worry about, it's interfering with other people, who have simple (cost effective) dishes and run multi-million dollar businesses (like TV stations!) with them. If you're interfering, someone is going to hunt you down and shut you off.

Here's a calculator someone cooked up that might be able to answer the question.

http://www.satsig.net/seticalc.htm

If you run with the default numbers (Aerocibo sized receiver+transmitter) the range is around 23 light years. The real numbers are going to be a bit different however, since our transmissions are usually not directional, but the transmit power is also higher.

Satellite is a high-latency service up to 500 to 900ms one way.

Uh. No. Satellite (at worst) is geosynchronous, which is 500 to 900ms round trip.

The result is that it's slow/unusable for many types of applications, which can't handle a 1 second round-trip delay.

By many applications, you mean some games. Video Teleconferencing works just fine. Many free offerings (such as Skype) work less-fine, but do still work.

In other words, it's not "broadband".

That depends entirely on the definition of "broadband". If you narrowly define it to include lower than 100ms latency (which I have never seen a definition do), it can't be. But if you just specify bandwidth...

You won't be comfortable trying to use VoIP over satellite, and streaming media won't work at all without a stout amount of pre-buffering.

Streaming media only needs bandwidth. VOIP only needs reasonably low jitter. Both are achievable over satellite. YouTube, internet radio, gametrailers.com all work quite well. I even know a number of WOW players who are on the far end of a satellite connection.

While it's far from ideal, it certainly beats dial-up, which may very well also have to pass data through a satellite transponder. There are areas of the country that are not even serviced by copper.

Well, it's not so much about linear spacing as angular elbow-room. Considering the 1-dB beam width at 14 GHz is around 0.7 degs, you could have ~500 orbital slots assuming they're all on the same frequency (no reusage). Still, you'd have some 500 km for each, enabling you to can cram some more with the reusage thing-y.

There simply isn't that much demand "sending small unmanned craft to do [unspecified] things".

You mean like these?

As far-fetched as it may be for you, unmanned craft are used for research (HST anyone?), communication, weather, navigation, electronic reconnaissance and remote-imaging (amongst other things).

From, http://www.satsig.net/ivsat-asia.htm :iDirect and LinkStar VSAT services from Apex Broadband

New lower cost business grade Satellite Internet solutions for Asia, Australia, New Zealand and the Pacific Islands starting from $160 USD per month for 512/128kbps.

Or they can just pay 160$ for a satellite connection. Or they can take a look at the current Mobile internet solutions as I am sure there would be cell coverage.

re 5) - I am having difficulty getting answers to what seems a simple question - can I get a satellite modem to do enough routing to run a firewall ? Surely this must be possible ?

Satellite Internet is already available and not that uncommon. Take a look at http://www.satsig.net/. We use satellite Internet here in Iraq and it works rather well once you adjust your systems to deal with the latency. I've got VoIP running quite well with it.

The article is more than a little short on salient information. I'd take a guess that they will focus a very high gain spotbeam on the Japanese home islands and provide a few wide coverage transponders as well. That will give them the power density to use small earth terminals within Japan.

Pricing is going to be the likely downfall of such a consumer oriented system. Relative to terrestrial broadband networks, satellite Internet is very expensive. For my current service, I pay ~$700/mo for 1M down and 256K up. Thats at a 10:1 contention ratio on a Linkstar (DVB-RCS MF-TDMA) system. Other plans are cheaper, but as the contention ratio goes up, the service delivered is only really suitable for very bursty non-realtime traffic.

While travelling recently I saw satellite internet being used on the islands in Thailand and also in the remote bush is Australia. For more info see Telstra Satellite Broadband (notice 1-way & 2-way options) and then this more general page. The only thing is that it was

It be best to buy the satellite internet reciever, hardware,etc. in the USA (or other free country), and then ship it into the country in question. You could then set up the reciever almost anywhere (including middle of the desert, rooftops,etc.), and still be able to get to the internet. Best of all, the company that owns the satellite is the one that is providing the internet, and therefore would probably not filter it. Also, it is almost impossible for the oppressive govnerment to know that you are using satellite internet, as long as you keep your interent presence anonymous (and you keep your physical location a guarded secret).

An excellent website that shows satellite internet coverage around the world is: http://www.satsig.net/ivsat.htm.

Ironically, the smaller dishes are easier to aim, since their gain is so much lower. Remember, a satellite dish is simply a telescope that operates on microwave frequencies rather than visible light, so a more powerful antenna "sees" a much smaller portion of sky, and consequently gets a much better signal. Having aligned 1.6-meter dishes and 12-meter dishes, I can attest that the 12-meter gets a great signal, but is harder to aim.

This site appears to have some useful information regarding satellite internet access.

>This may change with the launch of Dish's next satellite.

Dish has always had the upper hand on capacity. Here's the list of DirecTV satellites (via lyngsat):

101 - DirecTV 1R/2/4S
110 - DirecTV 6
119 - DirecTV 5

I don't know where DirecTV 7S is, it isn't listed.

And DishNetwork run satellites:

61.5 - EchoStar 3
105 - AMC 2
110 - EchoStar 6/8
119 - EchoStar 7
121 - EchoStar 9
148 - EchoStar 1/2
151 - EchoStar 4

That's a *LOT* of broadcast power. And with the Turbocoding (soon to be 8PSK) used on 105/121, that's twice the bang for the buck. Not to mention the option of 7/8 FEC over straight 5/6 QPSK FEC (all that DirecTV supports), they have much more to play with. They can squeeze a bit out of the failing transponders by setting the FEC to 1/2.

used to calculate the gains and losses on a link...
ya know.. sometimes you just need to know... BOOKMARK THEM!

http://www.satsig.net/linkbugt.htm
http://classwww.gsfc.nasa.gov/class/pages/FLBCalc. htm
http://nmsp.gsfc.nasa.gov/tdrss/calc.html

It's closer to get into geostationary orbit which is directly above the equator itself, but not orbit itself. That geostationary belt is pretty crowded airspace. It doubt it makes the trip up any easier since you still need to hit the same escape velocity (25,000 MPH / Mach 34) regardless of where you launch from. The challenge lies in achieving that speed as cheaply as possible, not an easy task.

Common myth. Let's look at the geostationary orbit (where most TV, telecom and weather satellites nowadays are) which is ~36000 km above the surface, i.e. it has an diameter of nearly 85000km and a length of over 265000km. So even if you require a minimum safety distance of 50km between satelites in geostationary orbit, there's place for over 5000 satellites.

Currently there are less than 300 AFAIK. (Here's a list of most of them). Please note that satellites which that are put put out of service usually will be parked in a "graveyard orbit" above the geostationary orbit - if there's still enough fuel and the motors still work of course.

The lower orbits (LEO, ~150-500km), where most military satellites, GPS, GLONASS, IRIDIUM and the like are placed is less problematic, since they are 'self cleaning' from old satellites: Objects there will deorbit sooner or later (the larger the sooner) since those orbits aren't very stable (due to earth's irregular shape) and the very thin atmosphere there reduces the orbital speed. That's why spacestations like Mir or ISS have to be boosted from time to time to higher orbits by a docked spacecraft.

The space debris problem is not caused by dead satellites, it's caused by all those tiny nuts and bolts left over from stage seperations, solar panel releases and so on which are affected much less by those deorbiting effects. Satellite and launch system designers nowadays take more care of this as they used in the 60-70s, e.g. the parts of the fairing which protects the payload of a launcher, are kept together connected by a wire or something after the fairing is ejected - the fairing just used to be blown up in seperate pieces by small pyros before.