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Broadband From The Sky In 2002?
Krendle writes: "A company named ISky is claiming that they will deliver high speed (2mbps down, 1/2mbps up) 2-way satellite Internet access by the end of 2001. One issue I've seen raised in newsgroups (in reference to satellite internet in general) is that of lag. With Internet applications like telephony and online gaming, etc., gaining popularity this is an important issue. 2Mbps from the sky still sounds cool to me, especially where we can't even get cable TV. What do you guys think -- will latency be a problem?" I'd be happy to "settle" for always-on wireless access faster than dial-up and cheap as DSL, but the iSKY Q&A page is short on price details. But it does say "iSKY is planning on being able to support all platforms including Macintosh, Linux, Solaris and Windows."
Contrast this with the older C-band technology (4 GHz) that is nearly transparent to rain, meaning no rainfade. The big old antennas you see in techies yards are for C-band. More power make it through the atmosphere (in both directions).
Now look at Ka-band: 20-30 GHz, even higher in freq than Ku-band. Rain/atmospheric fade has got to suck big time. The same-size antenna gets more efficient at the higher freq, but not enough to compensate for all the other drawbacks of the higher frequency.
Up to now all the Ka-band systems I'd heard of on the drawing board were for LEO systems, which bring you WAY closer to Earth and thus require much less power from both the satellite and the earth terminal. Ka-band and GEO? Yikes, off the top of my head I'd wonder about satellite power capabilities and FCC radiation limits.
And notice the "NASA uses Ka-band" blurb in their press release? Nobody else is doing it yet EXCEPT for NASA, because NASA is in the bleeding-edge business. Certainly the commercial race is on -- and has been for a couple years. But GEO?
The buzzword here is "link budget". Let's see how they do it. I'd love to hear from others here if you have any insight. My four years in the biz says keep your wallet in your pocket for now.
- Chris C., too lazy to set up a /. account
i mean, i wouldn't mind 2mbps on a laptop if i happen to be doing work in the field and i'm not close to an ethernet.
in these applications the latency isn't so much an issue as the having any connection at all to the internet. and 2 mbps is great for email or web research.
or is this impractical? blah! =)
"Just do me a favor, ok? Don't breed!" -- Adam Carolla, Loveline
Except modems are quickly becoming useless for gaming. I live in a town where if you draw a circle about 3 miles around my apartment, you have dsl or cable modems. Lucky for me, GTE and MediaOne have no clue if/when either DSL or cable modems will arrive. Anyway, playing many games with my 56k modem is futile. General public servers are overrun with higher speed folk, and well, you stand a much less chance of winning. No matter what the game, what part of the world the server is in, I see the same thing. A group of people with 50ms pings going against a bunch of people with 300ms pings. If you can find that rare server with other modemers, keep it well guarded. ;)
That's good. The bad part is they're partnered with EchoStar and won't support the use of real satellite dishes, just those stupid mini dishes. Everyone wants to create a little lock-in I guess. Everyone but the clueful customers.
Did you ever consider that the reason that Echostar uses those little dishes is because... drum roll...People want little dishes
If for some obscure reason you want a "big dish" Echostar sells larger ones, but then I would guess that you are not one of the "clueful customers"
From your comments I surmise you have no experience with satellite TV.
:-)
Ummm... actually I work for Echostar, although I'm in the software side of the house working on our new Linux based set-top box.
I'm not much up on the hardware though I know that we have 5 satellites up now with more on the way. Our new dishes are a bit bigger than the older ones and they can "see" at least 2 satellites to get up to 500 channels. The 2-way service will use an even bigger dish to see more. The C-Band dishes just aren't an option for most people in an urban area.
As far as getting stuck with a "custom" dish, it's not much of an issue since we are giving away the dish, set-top and installation for free when you sign up for service.
No, but in urban areas there are broadcast television stations and cable.
True, but I was an urban Echostar customer even before I started worked here. I just had enough of the local cable outfit...
Do you seriously think this is going to be a viable competitor to cable modems in areas where they are available? I wouldn't count on it. I get the impression a lot of cable modem users are into networked gaming...
My personal opinion is that it depends on the pricing. If the price is right, I think it will be a solution for some people. You'll be able to get HD TV (I see it in the lab here. It is amazing quality) and two-way satellite internet from the same medium size dish.
I'm in the middle of Denver, and I can't get a cable modem or DSL at my house, but I am on the Beta list for the new two-way satellite service. I'm really looking forward to it!
Jim
I doubt it, all the link encryption would be done in the hardware itself. I'm sure it'd just connect to your ethernet switch. Maybe with a serial console too.
-o
I'm on the end of a 1 meg satellite link right now, between the US and Australiam with RTT's of around 460ms. We can definately use this whole connection with multiple streams, but latency prevents the downloads from coming in at faster than 20Kbytes/second.
That seems like a reasonable figure. It still beats the 4.1KB/s I can get from dialup or the 14.4KB/s I could see from IDSL. I'd say it's not for everybody, but when other high speed options don't exist, it's a good thing.
/ k.d / earth trickle / Monkeys vs. Robots Films /
Large print giveth, and the small print taketh away
I'm not sure about the details and the implementation has to be really messy but while the latencies will still be kind of long you can stream data quickly and sort of do tricks to cut down some latencies.
I just took a job with Echostar and we are partnered with both iSky and Gilat, I'll send more details to slashdot when I can get them. The customer set we are really aiming at (I believe) are the out lying customers who can't get a DSL connection.
Yes, they will...however, Dish also recently signed a deal with iSky to also provide satellite internet services...
They figure they're going to need multiple providers to satisfy bandwidth demands from their customers.
I wanna beta test!
At the moment, the "iSKY Q&A page" link is pointing to http://slashdot.org.
-- K
We pump tons of energy into the air all day long, with pagers, cell phones, tv, radio, broadband... I just have to wonder - is there really no physiological effect?
---
I recall a long time ago on slashdot (yeah, rob.. you reposted, heh) somebody stated the laws of physics dictate latencies of atleast 300ms.
I don't have many details, but it will be in by fall of this year if I remember correctly.
What ever happened to those stories I read in WiReD a few years ago about the guys who were planning on building floating platforms that would hover in place over a metropolitan area and provide high speed wireless voice and data services? They were going to use some new technology to generate power from the atmosophere AND collect ozone-harmful CFCs at the same time.
Seems to me all the problems with satellite-based data services would be solved by something like this. :-)
The problem with iSky is that the satellites will be in geosynchronous orbit. Given someone else here posted that it takes 0.25 seconds for data to travel from a ground transceiver to the satellite itself (a sum total of 0.5 seconds for data to travel from transmitter to satellite to a receiver), that's way too much data lag for many purposes.
The better solution is the upcoming Teledesic system that should be operational by 2004. Unlike iSky, Teledesic will have a constellation of satellites orbiting from 850 miles up, so the transmission time from the ground to the sats will be far, far shorter. This means wireless data transmission rates at T3 line speeds (45 megabits per second) from anywhere in the world. This is perhaps the solution for people who need broadband Internet access but live too far away for cable or ADSL modem access.
Raymond in Mountain View, CA
That's why the Teledesic system is such a great idea. Because they will use 844 satellites orbiting at 850 miles altitude, you'll have a LOT less data lag (I've read that Teledesic satellites can offer at least 45 megabits per second data transfer rates anywhere in the world). That's the equivalent of a T3 data line.
This is the best solution that will cure our "digital divide" problem of getting broadband Internet access to rural areas far beyond the reach of cable and ADSL modems. I'm sure that when the system becomes operational the first places that will get Teledesic transceivers will be Indian reservations, most of which are FAR beyond the reach of even normal telephone lines.
Raymond in Mountain View, CA
Okay so these are geostationary satellites, they're in a fixed spot above the earth. This means they're at an altitude of approximately 36,000 kilometers, otherwise they'd move around the earth.
So each connection request will have to travel 72,000 kilometer, from earth to the satellite and back. If you'd request information from Europe, it'll have to travel another 8,000 kilometer, a total of 80,000 kilometer.
Now if you have a normal (DSL, Cable, phone) connection, this is only the 8,000 kilometer. The transmition speeds for copper or fiber are the same, so it'll take 10 times longer for your request to arrive at a server in Europe. And then the server sends a reply... For servers closer to you, the difference is even more dramatic.
Unless they come up with a whole network of low orbit satellites, ping times will be horrible.
If my memory serves, Larry Agustin himself warned investors that his stock was overvalued, which - naturally - caused me to stay far away from it.
The behaviour of the stock has to do with the "extraordinary delusions and madness of crowds", not the product or company itself.
I had my company purchase a VA Linux server, and so far the system has been flawless and I've been very happy with it. Now that the stock price has gone back to a reasonable level, I'd personally rate it a realistic buy.
I have a friend who suggested that I might help him invest in "this Linux thing" and make a few bucks. But I knew the valuations of Linux companies were sufficiently absurd as to make investment impractical, so I didn't take his offer.
Linux was a great system before these companies went public, it was a great system when they did, and it's a great system now. Nothing has changed but market hysteria.
I wouldn't blame Linux for the hype. Learn how to read a company financial statement, learn how to differentiate between profits and losses, and you won't get burned so badly in the future.
I know that sounds like flippant advice, but it's the cold, hard truth. Take that for what it is.
D
----
They don't mention any details on the upstream. Is everyone going to have a 20GHz broadcaster in their backyard? I wonder how they will work out issues of crosstalk between neighbors, I guess if this is only rolled out in low population areas it wouldn't be hard to distribute frequency so Abe's upload won't disturb Betty's download.
I wouldn't mind having a Long Fat Pipe (respect in the locker room) but I could always hi-jack a couple of neighbors DSL lines. I wonder if it would be possible to set up a communal DSL pool. A bunch of neighbors get DSL, and timeshare using all of them at once. So for 12 hours a week you get to use the full bandwidth of 30 DSL lines. Is there a router or something that can multiplex lines like that?
Scuttlemonkey is a troll
The solution to the bandwidth probelm is to launch more satellites. Spot beams and frequency reuse make such a system scalable.
That turns out not to be the case, for reasons which I pointed out in my original message.
Unless you have a really, really _huge_ dish on the satellite, you just can't focus a microwave beam very finely, due to diffraction effects. I'd already been assuming lots of low-orbiting satellites using spot beams when quoting my original figures. If, say, all of Manhattan fits in a spot, it doesn't help much.
if a satellite is at 300 km it will take a lot of fuel to keep it in orbit. that is impractical and very expensive
Satellites at any altitude take *no* fuel to stay in orbit. That's the definition of "orbit" in this context. An object in orbit is circling the earth quickly enough that centripetal acceleration in its curved path exactly balances gravity. Newton's Laws keep it circling forever (or at least many, many years, until the whisps of atmosphere at those altitudes cause it to slow down and crash).
regarding palm pilots with satellite links, let's not forget that microwave comm is line of sight. it not very practical in cities, mountains, tunnels, etc. forget about being inside man-made structures
Your cell phone is operating on microwave frequencies. Microwaves will penetrate a few wavelengths through most substances, and wave wavelengths on the order of a few centimetres. This means that they will happy pass through several tens of centimetres of brick, concrete, and what-have-you, which is enough for most locations (line of sight to a satellite that's *not* directly overhead doesn't have to pass through dozens of stories of a building - just the nearest walls).
Moot point in a city, though, for the reason mentioned above.
you have to be outside and know where your satellite to be able to talk to it
No, you just need a transmitter powerful enough that a satellite 300 km away can see its omnidirectional signals with sensitive detectors. A palm-pilot would have trouble doing this, but not a somewhat larger transciever in your briefcase (with a lower-power link to the pilot).
Again, though, you seem to be missing the point of my post - that satellite service to cities isn't practical for the bandwidth demands of a city.
>Satellites at any altitude take *no* fuel to stay in orbit
Actually no. Theoretically yes. But earth's atmosphere actually extends way way up there.
...As was clearly stated in my previous post. However, orbital decay due to atmospheric friction even in low orbit takes years or decades - the atmosphere's density drops off exponentially (not as one exponential, but as a piecewise-exponential curve). It's extremely tenuous and gets even more so as you go up.
Let's use figures from the ionosphere data you cite for density - about 1.0e12 particles per cubic metre at the most dense layer. Let's also assume low earth orbit, which has an orbit length of about 4.0e7 metres. This gives collisions with 4.0e19 particles per square metre per orbit.
By comparison, water has about 3.3e28 particles (molecules) per cubic metre. Air has about 2.4e25 particles per cubic metre at one atmosphere of pressure. Much, much denser.
Lets assume that you have a satellite with a mass of one tonne and a cross-sectional area of 5 square metres (solar panels and all). Assume it's in LEO with an orbital period of about 90 minutes. How long will it take before it loses 0.5% of its orbital velocity (enough to lower its orbit by about 70 km)?
Let's assume that all collisions are inelastic - that is, mass that the spacecraft collides with sticks and accretes. This will give an approximately correct answer and is easy to calculate.
The spacecraft's mass needs to increase by about 0.5% for inelastic collisions to lower its velocity by 0.5%. It needs to collide with about 5 kg of matter to do this. With an area of 5 square metres, that means 1 kg of matter per square metre.
Let's assume that air has a density of around 1.1 kg/m^3 at one atmosphere (I may be off by 0.1 or so, but that's close enough for these purposes). This gives a mass of 1.1 kg * (4.0e19 / 2.4e25) = 1.8e-6 kg per orbit.
At 90 minutes per orbit, this means 4.9e7 minutes for orbital velocity to be reduced by 0.5%, or about 90 years. That's considerably longer than the expected lifetime of the satellite's electronics.
In summary, for anything placed in LEO or higher, it will be something other than orbital decay that determines satellite lifetime.
However, don't expect satellites to replace cable any time soon. There are difficulties when you try to scale up to the silly bandwidth levels required:
Your satellite is at least 300km up, and making microwave beams really parallel is tricky (unless you want to use a huge dish, which adds weight and cost to the satellite). This means that, even pulling tricks like having multiple fairly-narrow-angle transcievers per satellite, you still get everyone within a few tens of kilometres sharing the same uplink. Fine for low-density areas, but not for cities.
Microwave beams have a data bandwidth comparable to their frequency - a few Gbits/sec. at most. This is the maximum _shared_ bandwidth per uplink region, and the maximum bandwidth of the pipes between the satellites. Bump the frequency up to get more bandwidth, and you start getting blocked by light cloud cover and thin walls (and ceilings). While you could do something like have an optical link from satellite to satellite, your uplink/downlink bandwidth is going to be pretty crummy compared to, say, a fiber backbone serving the same area.
I'm not trying to bash satellite data services - as mentioned above, they do have their uses. I'm just trying to stave off the inevitable flood of "Wow! Now everyone in the city can get cable bandwidth from their palm-pilots!" messages.
To cause damage to animal or plant tissue, electromagnetic radiation needs to either cook it by raising its temperature (lots of watts, like in a microwave or a solar reflector), or have ENOUGH ENERGY PER PHOTON to ionize it. Radio wave and microwave photons don't have enough energy to ionize or break chemical bonds in living tissue. They're less dangerous than infrared radiation (heat). UV, X-rays, and Gamma rays have enough energy per photon to ionize or break chemical bonds in living tissue.
Yes, let's talk photons. It turns out the situation is not as simple as it first seems. The energy from a microwave photon eventually ends up as heat, but you could easily argue that for every other form of EM radiation as well. The question is, what happens in the interval between the time the energy is adsorbed, and the time it ends up as waste heat?
Basically, microwaves set up a rapidly oscillating electric field in the material they pass through. Polar molecules (Such as water) experience a torque that aligns them in the direction of the elctric field, and which changes direction each time the field reverses direction. What makes water an especially good adsorber of microwaves is their network of hydrogen bonds, some of which must be broken to allow the molecules the freedom to rotate with the field (Note--hydrogen bonds break and reform all the time, it's one of the properties that allows water to flow).
Now, what happens to biological molecules is something that is not understood well. We do know, though, that polar molecules will experience forces that unlike those from normal thermal agitation, in that the forces are non-random.
In vitro, microwave energy can cause subtle but repeatable changes in gene expression and protein activity (Such of those like heat shock proteins) in ways that differ from those observed with simply application of heat. Go to PubMed and search for the term "Microwave Exposure", you'll find there is actually quite a bit of research on the subject.
If we spin the planet faster, we move the geosync orbit closer.
- Put rockets on the equator, with the exhaust pointing west.
- Compress the planet so that it has to speed up in order to conserve angular momentum.
Any other ideas?---
As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
Their web site says their satellites are in geosynchronous orbits.
Geosynchronous orbit is 37500 km. This translates into a minimum roundtrip speed-of-light latency of 250ms.
Any netrek player will tell you that that amount of latency is too high for effective gaming!
Err. There weren't any QA jobs here to begin with.
(I don't regularly troll Slashdot, either. It's just that this was asking for it.)
Actually, it depends on the size of the dish they give you.
An 18 inch dish, like is used with DirecTV and Dish Network are really the absolute minimum size that is useable. It takes a really big thick cloud to knock out the signal you receive when you have one of these dishes.
However, you can use (and DirecTV/Dish have them available) 24 inch dishes. They give you a lot better signal reception and the nasty storm cloud effect is all but fixed (unless it is a really really really big cloud).
Transmitting, on the other hand is a bit different story. I am assuming this thing is going to be pretty low power - it would have to be unless this outfit wants to have a lot of it's customers burned by RF when they stand in front of the dish, which would be very very awful. Trust me, RF burns are not fun at all.
So, the dish is probably going to increase in size to 36 inch (like Primestar had) or maybe even bigger.
They're planning on supporting all platforms.
I thought they should just support tcp/ip over ethernet, and be done with it..
Your latency data point from your wireless network is useless. 2.5km is a much smaller number than 36000km :)
Do the math - light (and therefore RF and therefore wireless signals) travel at 300000000 meters per second. Your wireless round trip is 5km, 5000 meters, so that takes .016 milliseconds. Now, if that signal has to reach a satellite 36000000 meters away, that's going to take it 240 milliseconds. So yes, it is exactly equivalent to gamers playing over DirectPC :)
The satellites do make a good solution for people who don't want to live in neosubopolises. So far, neither telephony nor cable cos have expressed much interest in serving the rural communities. As someone who would like to retire someplace remote, it'll be nice to have a solution when I no longer desire, nah, require Quaking of some sort...
--
+&x
I'm sure the poster was well-intentioned, but you REALLY SHOULDN'T speculate about things you know nothing about and start trying to scare people. We know a lot about radio waves, LOTS of research has been done. And they aren't dangerous at these levels.
This satellite or cell phone radiation scare is one of those things that just doesn't die, no matter how many times the vast majority of scientists (plus or minus a very few crackpots) try to set things straight.
To cause damage to animal or plant tissue, electromagnetic radiation needs to either cook it by raising its temperature (lots of watts, like in a microwave or a solar reflector), or have ENOUGH ENERGY PER PHOTON to ionize it. Radio wave and microwave photons don't have enough energy to ionize or break chemical bonds in living tissue. They're less dangerous than infrared radiation (heat). UV, X-rays, and Gamma rays have enough energy per photon to ionize or break chemical bonds in living tissue.
If microwaves were so dangerous, we would have all already been killed by the cosmic background radiation left over by the big bang.
Since when is everything about gaming? ;) ;)
Seriously, there's lots of people living out there in the Boonies, and even some of them aren't rednecks. I'm fortunate to live in a city where you can get ADSL, and I know most of my bandwidth doesn't go towards gaming.
And just think of the coolness factor when people talk about their connections:
"I've got a 56K"
"I've got a cable modem"
"I've got a satellite uplink"
Sounds alot like something from a Bond movie!
--C
It's only software!
Yes, lag is an important issue (inherent in the distances between earth and satellite combined with the speed of light), but its importance in a given application depends entirely on that application. If you're trying to play Quake, then you're SOL. If you're streaming audio from a shoutcast server (or downloading naughty pictures like most users), you won't take such a hit. But like with most of these technologies, it'll be embraced eagerly precisely by those who have no other choice, while the rest of us snicker with our T1s and cable modems.
"If one is really a superior person, the fact is likely to leak out without too much assistance" -- John Andrew Holmes
Even if latency is a huge problem, I won't be bothered. I'd much rather have slashdot come ripping down the airwaves at me at 2mbs after a 1 or 2 second lag than it slowly trickling down my modem connection at 56k.
Doing large amounts of downloading (basically all i do) won't be a problem with lag, now gaming is another issue, if you're a die-hard gamer, you can spare the expense of having a modem connection for games, and just use your satellite for downloading mp3s, or websurfing.
UFO-1
Stands for UHF Follow On... Part of the Military Strategic Communications fleet (reads, pre-MILSTAR). Low data rate of 75 baud, used for EAM's and such.
These satellites were designed to take over for the aging AFSAT fleet, but only until MILSTAR came on line. Go figure that the AFSAT birds were only supposed to fly for 5-10 years, (launched in 70's) and 'all' are still in use.
Q-Hack!
Some days I get the sinking feeling Orwell was an optimist.
We only need to reduce the equatorial radius. So put the rockets at the poles and stretch the planet into a thin ellipsiod. This has the other effect of making almost everywhere tropical.
Or we could use one of those wormholes to move the planet to a universe with a higher speed of light.
Or we could breed humans with lower reaction times (or just chill existing ones) so 500ms seems really fast.
while(1) {fork();}
Latency - It may or may not be a problem depending on the application. It will definately be useless for gaming. Geo-syncronous satellites have a 1/2 second round trip delay. This delay is even noticable in voice communications. Until the speakers get used to it, they have a tendency to both start speaking at the same time.
That is only the delay caused by distance. There may be additional delays due to the communication protocol.
Local Protocol - Their page says that they will support EVERY OS. I interpet this to mean that it will be a stond-alone box that will support the common LAN protocols (TCP?IP, ISX, etc.) and act as a router. Use your normal network software and point to the Isky box as your default router.
Satellite Protocol - As someone has already pointed out, TCP/IP is useless over a satellite. However, this is not a major problem since there are several existing protocols that do work well over satellite. The ISKY box will just convert between the protocols.
Hughes Network Systems already does this with their PES (Personal Earth Stations). It is called 'IP spoofing'. Basically, the box will act like the end connection and provide the ACKs and NACKs. It will keep the data in its memory until it has determined via the satellite protocol that it has been successfully transmitted.
Downlink - Nothing earth-shattering here. Hughes' DirectPC already does this. Just split the channel into time slots with an address field. As data comes in, stick it in a slot and put in the appropriate address field.
Uplink - This is the tricky part, which is why DirectPC requires that you have a modem uplink.
There are two ways to share satellite bandwidth: Frequency sharing or time sharing. Satellite bandwidth is too expensive to give each user a dedicated chunk of the frequency.
Time sharing has another set of problems. How does the users box know when to transmit? If you assign each customer a slot, then you are back to the cost issue since the slot isn't unused if the customer has no data to send.
Another option is the ALOHA channel. This works similar to the CS/CD (Carrier Sense/Collision Detect) of ethernet. Because of the delay from when a station starts to transmit till the time others can sense the carrier, this is an ineffiient means of utilizing bandwidth. The maxium throughput is about 10% of the allocated bandwidth.
The only option that I can see is use an ALOHA channel with a small but reasonable data length. That way short transmissions, e.g. request a web page, would go through the ALHOA channel; while longer transfers, e.g. uploading through FTP, would be converted to a request for an assigned slot.
The major problem with this solution is that it adds to the latency. When data goes over the ALOHA channel, there is no guarentee that it will be received due to the possibility of a collision. Since the round trip delay is 1/2 second, the box would have to wait from 3/4 to 1 second for an ACK. If it doesn't receive it, it will have to retransmit.
I feel like picking a fight with everyone who thinks they are right. - Rainmakers
Ok, I'll do the math on how many transmitters are down here and even at 3 or 4 sigma there is bound to be one stuck on relatively frequently. Won't that be a problem? -- effectly being a DoS.
What are they going to do about the 'stuck on' transmitter problem (be it simple hardware failure or something more unpleasant)? How does one go about finding that transmitter? ("Hey, NSA, could you over-fly the entire US with your radio receiver listening to this freq....")
The existing gas-station style uplinks are relatively tightly controlled... This opens up a whole new class of problems.
Obviously you want a circuit that limits xmit times, but as we prove on /. everyday. "S**T happens". Things get hit by lightning, bad batches of parts happen, etc etc etc. Sooner or later one of these uplinks (perhaps in a DoS attack) will be on and there will be nothing to do but track down the source. How does one go about doing that?
It took the FBI months to figure out who captured the HBO transponder in the late 1980s. I seriously doubt that the FBI will use that many resources for just a sat based ISP. What is going to prevent their service from totally dieing while that transmitter still transmits?
Don't see anything technically wrong with it. Spot beams to limit sharing of bandwidth, reasonable 26-inch antennas, nothing magic about the technology. Cost of transmitting ground stations at each consumer might be problematical.
Useful mainly for *very* rural areas where other wireless internet would be impractical, or for supplying ISPs in those areas with bandwidth. Not good for playing Quake or similar, as noted, and would expect periods of brief solar outages for a few days twice yearly.
For those without other access and who can afford it, looks fine.
well then, off topic, this brings up the fun realm of extrapolation... but still, 2.5km and 36000km really dont make a huge diffrence at the speed wireless travels. I've used Satalite phones on islands, they lag, but it's not bad unless you're a stock broker, which is basiclly equivlent to gamers playing over directPC or a new bidirectional satalite based internet feed. :P
So anyways...thats 2 more all of you owe me
-GuS
Q. What's it take to get a story posted on
Hi, just figured I would ass my 2 here. /.ers to be) the latency shouldnt be a problem. Email, web, FTP, and say, CC authorization, and maybe even a small webserver would run fine over these connections. :)
I currently sit on a 2.4 GHz wireless lan (breezecom pro.11-D to be exact) which handles almosy 3mb on the wan and has a T1 to the net... the distance from point to point is ~2.5km and on the WAN I notice latency ~12ms and to the internet ~200ms. I am not a huge fan of Quake, but it seems to run fine, other games such as EverCrack run just fine... websites fly, and well.. I have no complaints. So on the subject of satalite connections, I think that for most home users, (not power users, which I find most
To address the problems of picking up a large area of signals making some satalites lagged if they fly over dnesly populated areas.. I can think the most simple solution to this is fly multiple satalites over an area and make them addressable, the internal bandwidth of these things could be 100's of gigabits, and they choose based on it's address which packets to then route to their land based internet feeds...see where I'm going? competeing cell phone companies do this kind of stuff.
Of course the other option is to have satalites opperating at diffrent frequencies over the same area, that woudl work too.
Anyways hope that adds to this
-Doug
Q. What's it take to get a story posted on
There are a couple of external factors involved in the pricing of digital satellite service. First, it has to compete with cable in areas where cable is available. I've compared the pricing. It looks like satellite services substitute a few more (non-local) channels in place of the local service they can't provide at very similar price points for their packages in our area at least.
Second, they have to build sufficient volume to keep the price at that level. The equipment that they have to maintain is different from cable. The cost per user scales quite differently. With cable, each new neighborhood needs its own lines. With satellite, the infrastructure is centralized or in space. It gets paid for in big chunks.
They'll be competing with cable modems, DSL, and for rural users, ordinary dial-up access. And they are comping in after those services have gotten a head start. They are going to have to sell an attractive package, or they won't generate the customer base they need to keep going.
The net will not be what we demand, but what we make it. Build it well.
According to their Tech page they are using GEO stationary birds, this will be much more latent than say Teledesic's LEO (Low Earth Orbit) sattelites.
You won't Quake with iSky, well you might, but you will die quickly.
If these satellites are geosynchronous, then the latency will be terrible. For regular landline links, nominal transcontinental latency is about 16.5ms (but much more since light travels more slowly through fibre than through a vacuum, and this figure also doesn't account for routers and such). So just imagine what the latency would be like for a sat that is 28K miles up. However, Iridium is LEO (Low Earth Orbit) and would be perfect for this since the latency would be so much less. Motorola, are you listening?
'He who has to break a thing to find out what it is, has left the path of wisdom.' -- Gandalf to Saruman
Lots of companies are developing broadband services using satellites. MSN/gillete, an AOL venture and many more are due in the next year and after that speeds gets very high. Specs are at 60 mpbs in 2001-2002. These services are also supposed to rival DSL and cable for their price and whip them both in speed.
Colm Atkins
The other thing I would add is that the 250ms latenncy is only the physical layer. If you add on the rest of the networking required for data to reach a wireless device, it won't be uncomon to see 500ms or more.
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Actually no. Theoretically yes. But earth's atmosphere actually extends way way up there. I mean, it's a gas, and the molecules in a gas move, well, damn fast. The distribution of molecular speeds in the gas is stoichastic (pertaining to a random process), and also the upper layers can be, well, a bit warmer than down here. (Some are much colder too... don't ask me how it all works).
Anyways, the atmosphere doesn't just 'stop' at 100 miles, and so there is a big region where satelites will orbit for N years ( N being anywhere from 0 to infinity) while their orbits degrade... Certain events (solar, etc) can 'puff out' the atmosphere, causing a bit of variability in the decay of some orbits.
Here is a graph on the ionosphere.
And one on the temperature range of the atmosphere, with the exosphere going past 500 KM.
And a nice general NASA page on the atmosphere, focusing mostly on stuff below the exosphere.
Anyone out there got a paper or graph of orbital decay physics? I know personally that I've seen writups showing lists of satelites, their orbital paths, and their expected decay times (which ranged from 10 years to 100,000 or more)..
Company, Date Expected, Download, Upload
AOL/Hughes DirecPC, 2000, 400 Kbps, 56 Kbps
MSN/Gilat, 2000, 400 Kbps, 56 Kbps
iSky, 2001, 1.5 Mbps, 0.5-1 Mbps
AOL/Hughes Spaceway, 2003, 400 Mbps, 16 Mbps
AstroLink, 2003, 226 Mbps, 20 Mbps
Teledesic, 2004, 64 Mbps, 2 Mbps
iSky is the first to be able to be called truly broadband, but soon afterwards, it appears like it could become obsolete with AOL offering download speeds supposedly 266 times faster!
The article also mentions (I do not know if this has been said before or on the iSky site) that iSky will probably cost around $200 for setup and $40 per month and be national. So its comparable to costs of other broadbands, plus you can get it anywhere.
If big companies like AOL and MSN are putting their weight in such ventures, I am sure this could get promising... but what do I know? :)
This is another company that was going to IPO and then decided not to because of recent market downswings. I also think that maybe they didn't IPO for some other shaky reasons in their economic strategies.
Mike Roberto (roberto@soul.apk.net) - AOL IM: MicroBerto
Berto
That's good. The bad part is they're partnered with EchoStar and won't support the use of real satellite dishes, just those stupid mini dishes. Everyone wants to create a little lock-in I guess. Everyone but the clueful customers. I predict that they will not get enough customers and eventually go bankrupt. It's a shame, I could really use the bandwidth, even with the latency, but it looks like I'll be sticking with my dialup. DSL is supposed to be coming soon anyhow.
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Friends don't let friends enable ecmascript.
From your comments I surmise you have no experience with satellite TV.
The reason EchoStar likes little dishes is because they tune only one satellite - the one EchoStar (or their competion if it's not an EchoStar dish) uses. Hence the "lock-in" factor I mentioned. The large (typically called "C-Band" although it can also access other bands) dish can access any satellite, and the large dish owner can buy programming from a number of competing providers, at lower cost because of the competiton of course, in addition to having access to hundreds of free channels.
If you had the choice between a standard modem that could access any ISP, and a custom modem that worked only with one ISP (and becomes useless if that ISP goes under, or if you decide for some reason to go to another,) would you really want the latter?
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Friends don't let friends enable ecmascript.
Geosynchronous orbit is about 30 000 km, so 100 ms delay at speed of light. Up and down means 200 ms latency. Now how bad is this?
...) it'll be OK, I'd just forget about remote X applications though. Voice over IP might have problems too.
I tried a couple ping (note, I'm in eastern Canada):
www.slashdot.org 35 ms
www.linux.com 110 ms
www.inria.fr 130 ms
www.csu.edu.au 400 ms
The ping is round-trip, so you need to divide by 2. Basically, the latency introduced by a satellite isn't that bad compared to what we've got now. Of course, it will depend a lot on the routers (I've already seen 5000 ms to go 5 km).
I think for most applications (web, ftp,
Opus: the Swiss army knife of audio codec
Even though cellular services are just now getting rampped up in medium sized markets, they will be the mobile way to go in a year or so.
"Well, good luck finding a judge that doesn't run a bestiality site."
That is somewhat easy. Just design the transmitters to have a TX_time_out variable that won't let the tranmitter stay on for more than a few seconds.
"Well, good luck finding a judge that doesn't run a bestiality site."
Right on! Keep the faith!
This was my business (engineering on-line networked games on the internet) a job ago so let me set you straight. "Speed" is a much abused term. It can refer to Bandwidth, Latency, cxonnect time, or any combination thereof. Geosynchronous orbit is VERY high up. The speed of light believe it or not is your limiting factor. Bouncing a singal off a geosynch satellite takes a LONG time in terms of ping/latency times. This is unavoidable by this century's understanding of physics. Speed of light is fixed. Satellite commuicatio nis genreally high bandwidth, and "always on" thus low conenct time, but latency is bad. When they talk about "analog modems" its kidn of a straw man. Analog modems are old, bad technology. They will beat a stellite in tyerms of "normal" latency BUT they are prone to latency spikes from the "retrain" when they have trouble with the line that can be as large as 6 seconds. Theya re also very slow to connect. Analog mdoems though are goign out of service fast. The currently expanding technologies are xDSL and Cable Modem. Both are always on and low latency (much lower then a satellite can possibly be)but they do not have the kind of bandwidth a staellite can potentailly pump at you. Hope that answers your questions
Once you get past DSL speeds I find the limiting factor is latency, not bandwidth. Here at school the T3 is great for Quake
I can play Quake over the WaveLan network here, too, and it's playable. My ping times are typically ~150ms compared to a ~20ms ping on the wire. I expect satellite would be horrible for this; if 50 feet of radio gets me 150ms latency; what will the miles and miles to orbit do?
Is anyone working on high-latency modifications to TCP?
Just wait until the new Lincoln Navigator comes with a Dish on the roof and a wireless basestation providing a net link within a 1000 ft radius.
OTOH "I'll give my presentation in just a minute, I have to move my vehicle to the front parking lot."
This sort of service could be really useful for the travelling salesman types who need full net access.
Then again it could really ruin your back to nature vacation when you are in the remotest part of Glacier Natl Park and some Net Phreak comes walking by with one of those friggin Satelite Backpacks and you can help yourself from asking him if you can check your e-mail/stocks etc.
Ahhh technology
no sig.
that this kind of service will have a place in the world... perhaps for mobile computing? I wouldn't want to use it for standard service from my desktop if DSL or Cable Modem is available. Not sure about telephone modem... it would depend on how badly I need the higher throughput.
Gonzo
Does anyone know if anything like this has (or if not, is ever likely to) hit the UK? I am fed up of reading about you guys and your posh fast connections... We're only just getting free local internet access and ADSL launched later this year! Makes me so jealous!!!
So what about security? Anybody with a receiver would be picking up your download, your mail? And you'll also upload to these satellites? So how much power does that take? Is that even legal to broadcast radio waves? Will they make it legal? Will the service degrade with increasing usage? Can I use the receiver to decode TV signals ?;)
What if it gets cloudy? How bad a latency are we talking for a cycle?
(The RV idea is good though)
You can't handle the truth.
Latency doesn't just affect interactive applications like games and VoIP. TCP uses the latency of packets to determine its window size, and hence the download speed. This is the part of TCP that sends data to your modem at 56Kbps instead of forcing it on you at the full available bandwidth where you can't receive it anyway
With a 400ms RTT (what we see on geosynchronous satellites here) you're looking at a maximum stream speed of 20Kb/s.
So while you might have 2 megs of bandwidth, it's still no killer. You're lucky to see 150Kbps of it at a time unless you're downloading multiple files simultaneously.
It sounds and looks good and all. But, I have to worry about security. I mean how hard is it intercept a signal here. It happens all the time with cell phones and god knows how many people are getting free Satelite TV service. So, how difficult would it be to point my satilate dish at my neighbors house and intercept everything they are sending out (passwords, cc numbers. etc.... etc...) I know it isnt *that* easy, but again..... it can't be that impossible either.
ON the other hand, I suppose DoS attacks would be harder to carry out against a 2mps conections.
jsut some questions Im wondering here.. oh hummm
"I mean, All you can definately say about a fellow who thinks he's a poached egg, is; He's in the minority." James Burke
considering all your PRO-Micro$oft stance, I am not suprosed to see you make such a post. What would suprise me less is if you are one of the AC's throwing out all the troll bait.
/.
/.ers out there, but it does fit into the category of "news for nerds"
Now, why is Linux such a big theme on
Well, if you would stop throwing out troll bait you would see that Slashdot's motto is "news for nerds stuff that matters"
Nerds like tech stuff we can play with.
Linux is open source
we get to tinker with it
therefore, it is important
Microsoft isn't open source
we dont get to tinker with it
so it doesnt matter to us
And yes, I know it doens't aply to all
Now why does a VA stock drop not make news here?
well, probably, if this was Slashdot: "news for investors, stuff that matters" then it would.
but it's not so it doesn't.
Finaly (to the trolls), if you really want to impress me, then use a few less of those lovely adverbs and a few more valid arguements. But, acting like a total idiot is only going to get me to reat you like a total idiot.
just my $.02
"I mean, All you can definately say about a fellow who thinks he's a poached egg, is; He's in the minority." James Burke
Pretty simple to solve that...many terminal apps allow you to type in a text box at the bottom of the screen before sending it to the server.
Cool applet!
Did anyone else notice the "satellite" named UFO-1 flying around?
I bet Iridium is scraping around for that undo button right about now...wonder if they would of been able to use those satellites for ISky.
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"Ford," he said, "you're turning into a penguin. Stop it."
Which sounds faster? Its a marketing thing!!
Skiers and Riders -- http://www.snowjournal.com
No, TCP determines the window size by the paket loss on the connection
(Paket loss = congestion for TCP), that's why standard TCP isn't usable for mobile communication with bad links, like cellular phones.
However large latency (in fact a large bandwidth*delay product)
limits TCP performance: The sender may only send a complete TCP window into the network and has to wait for the ack's before sending new data. The standard TCP window is maximum 64k and therefore the maximum throughput is 64k/2*delay.
However, RFC 1323 provides a fix for this problem: a larger TCP window limit. The question is, if this is supported by the standard implementations. Keep in mind that the receiver must provide a large receiver window, too, that's the next problem.
You are the dot in slashdot !
UMTS the 3rd generation cellular system will deliver bandwiths up to 2Mbps and is a successor of today GSM systems.
In the case of Iridium the evolution of mobile phones rendered this business obosolete. I wonder now what is going to happen to iSKY. Especially since the first UMTS operations will be launched in 2002. UMTS supposedly will be comprised of a mixture of terrestrial and (optionally) satellite based relays. Finally it will be (hopefully) the first world wide standard for mobile communications.
I wish them good luck, but I am afraid that this might be just another Iridium.
For more information on UMTS, have a look at:
http://www.cellular.co.za/
(Note: I am not affiliated with them in any way.)
for areas with no DSL, or Cable access. What about the 2 way satellite @ 64 Mbps downsteam not sure about upstream. Anyone know anything about it?
Performing the calculations, .47751 seconds.
(22,238 miles X 1609.344 meters per mile)/(299,792,458 meters per second) X 4 trips =
See this Byte article for further discussion of TCP and latency. Also see this student article for a discussion of alternatives.
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I18N == Intergalacticization
Don't ever plan on using it as a Quake server ... Sattelite is cool and all ... but they are going to have the exact same problems DirecTV has with their Web Access .... over 1 second ping time ... it's not so bad if you are running a BBS, FTP Server or even a Web Server ... where 1 second doesn't mean TOO much ... but again gaming would be horrible.... you'd be dead before you start!
DaiTengu
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Damage Inc. BBS
- linuxtv
- inria.fr
- dvb.org
- protocol notes
- gilat
- europeonline
- drdish
- helius
- telemann.com
- broadcast.philips
regards