Broadband From The Sky In 2002? 99
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."
Ka-band = killer rainfade and bleeding edge tech (Score:1)
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
isn't the real use in wireless? (Score:1)
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! =)
Re:latency won't bother me (Score:1)
Re:Hrmm (Score:1)
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"
Re:A clue (Score:1)
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.
Re:A clue (Score:1)
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
Re:Gee (Score:1)
-o
Re:TCP wasn't made for satellite (Score:2)
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.
DirecPC? (Score:1)
/ k.d / earth trickle / Monkeys vs. Robots Films [homepage.com] /
Re:Geosynchronous orbits: 250ms latency. (Score:2)
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.
Re:DishNetwork will be doing this with Gilat servi (Score:1)
They figure they're going to need multiple providers to satisfy bandwidth demands from their customers.
I wanna beta test!
Screwy link... (Score:1)
OW! My Brain! (Score:2)
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?
---
latency.. high.. packet loss.. yes.. (Score:2)
I recall a long time ago on slashdot (yeah, rob.. you reposted, heh) somebody stated the laws of physics dictate latencies of atleast 300ms.
DishNetwork will be doing this with Gilat service (Score:2)
Hovering platforms over metropolitan areas (Score:1)
What ever happened to those stories [wired.com] I read in WiReD [wired.com] 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. :-)
iSky too far away; Teledesic better (Score:2)
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.
Re:This is neat, but reaches limits very quickly. (Score:2)
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.
Latency (Score:1)
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.
Re:I'd like to take this moment to say something i (Score:1)
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
----
How do they do upstream? (Score:2)
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?
Um, wrong. (Score:1)
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.
Re:some nitpicks (Score:1)
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.
Orbital decay. (Score:2)
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.
This is neat, but reaches limits very quickly. (Score:4)
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.
Microwave Energy and Biological Systems (Score:2)
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 [nih.gov] and search for the term "Microwave Exposure", you'll find there is actually quite a bit of research on the subject.
Re:Geosynchronous orbits: 250ms latency. (Score:1)
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?---
Geosynchronous orbits: 250ms latency. (Score:4)
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!
Re:Get used to it (Score:1)
(I don't regularly troll Slashdot, either. It's just that this was asking for it.)
clouds and radio (Score:2)
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.
Gee (Score:2)
I thought they should just support tcp/ip over ethernet, and be done with it..
Re:Earth Based wireless (Score:1)
Re:Earth Based wireless (Score:1)
Re:It's wondeful for some things (Score:1)
--
Let's talk photons, you crackpot! (Score:1)
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.
Re:Microwave Energy and Biological Systems (Score:1)
That sounds good (lots of handwaving about dipoles and such), but these tests that proclaim an effect of microwaves on gene expression don't hold up to scrutiny. I found only one paper, from the early 90's, which claimed to measure the effects of microwaves on gene expression. And again, this is due to HEATING by INTENSE microwave pulses. Like putting a cat in a microwave oven. We're talking kilowatts, or higher, per cc.
Sure, microwaves can break very weak bonds, such as hydrogen bonds, that are broken and reformed all the time at room temperature. In any case, the best physicists and chemists can't seem to get any net, measurable, non-uniform breaking of hydrogen bonds in solution by using microwaves. The effect is identical to heating. If someone did achieve non-uniform bond breaking using microwaves, they'd make millions or billions from the idea, using it to reduce side reactions, increase yield, and so on. Of course, microwaves ARE used in chemicals processing, but for heating, not for quantum control. And there are chemists and physicists trying to develop quantum control of chemical reactions, using ultrashort pulses of near IR, visible, and UV light.
I still say the vast majority of knowledgeable chemists and physicists (such as J.D. Jackson at Berkeley, who is quite vocal on this topic) concur that there is no effect of low-level radio waves on living tissue. So you can all take off the aluminum foil hats and relax.
Re:Ping Times (Score:1)
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 wondeful for some things (Score:2)
latency won't bother me (Score:2)
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.
Re:GEO 250ms latency + LandLink+ Netlink + Nic+OS (Score: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!
Other options (Score:1)
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();}
Re:OW! My Brain! (Score:1)
My Thoughts (Score:1)
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.
Re:air broadband -- do the math (Score:1)
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.
Re:air broadband -- do the math (Score:1)
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?
Re:Geosynchronous orbits: 250ms latency. (Score:1)
Okay ...
Distance is 37,500km = 37,500,000 m.
Light speed = 3 x 10^8 m sec^-1. = 300,000,000 m sec^-1
37,500,000 m / 300,000,000 m sec^-1 = 0.125 sec. for one leg (up to the satellite)
Multiply this by two and you get 0.250 sec from your demarcation point (the LNB on your satellite dish) to the other side's LNB.
As others have pointed out, though, this does not take into account other latencies (and we have a seven-layer network model here). Plus, you might even have to go through multiple satellites, depending on where you are and how this ISP configures its systems. I'd say to be safe, multiply our calculated latency by two, and maybe even by four.
So we expect half-second to 1-second delays. That's unacceptable for most applications. Games are a concern, but frankly aren't that important in the grand scheme. We're talking level-3 switching for voice-over-IP and whatnot. A 1-second delay won't even support full-duplex.
Doesn't seem to me like this is very realistic, although for downloads the bandwidth would sure be nice. For real-time applications, though, I'll stick with a landline, thanks.
A quick look (Score:1)
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.
Re:OW! My Brain! (Score:1)
From the NOAA Space Weather scales for solar radiation storms at http://sec.noaa.gov/index.html comes: "S5: severe [...] high radiation levels to passengers and crew in commercial jets at high latitudes (approximately 100 chest x-rays)."
Seriously... the universe itself is full of hazards. Maybe you should wear a tinfoil hat?
Re:Earth Based wireless (Score:1)
So anyways...thats 2 more all of you owe me
-GuS
Earth Based wireless (Score:3)
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
Re:Gee (Score:1)
Re:isn't the real use in wireless? (Score:1)
Re:Gee (Score:1)
DB
Interesting pricing information (Score:3)
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.
Sattelite Latency (Score:1)
You won't Quake with iSky, well you might, but you will die quickly.
Ahem! Iridium, anyone? (Score:1)
air broadband (Score:1)
Colm Atkins
Re:GEO 250ms latency + LandLink+ Netlink + Nic+OS (Score:3)
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.
___
Re:Latency (Score:1)
As far as other celestial objects' gravitation tugging on the staellite, those forces are dwarfed by the Earth's gravity.
Re:some nitpicks (Score:1)
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. [haystack.edu]
And one on the temperature range of the atmosphere, with the exosphere going past 500 KM. [haystack.edu]
And a nice general NASA page on the atmosphere, focusing mostly on stuff below the exosphere. [nasa.gov]
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)..
Other Web Satellite Services (Score:1)
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? :)
iSky seems insecure (Score:1)
Mike Roberto (roberto@soul.apk.net [mailto]) - AOL IM: MicroBerto
Hrmm (Score:1)
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.
A clue (Score:1)
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?
Re:A clue (Score:1)
Ahh, thanks for making that clear. Our experiences are from radically different perspectives. I live in a rural area, with satellite the only option for tv. I don't mean the only option for premium channels, I mean the only option for TV period (well we get in one broadcast channel, but the signal is too weak to get video - it's sound only :P) Not that I am much of a TV person, but in this day and age it's nearly a necessity, and of course in this sort of community all the neighbors know each other and talk - they all have satellite TV in one form or another too.
No, but in urban areas there are broadcast television stations and cable.
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...
That seems to be a fairly common offer with small dishes, several neighbors have gotten that sort of deal on tv service. It seems like a good deal at first, because of the low-to-no initial investment. But over a period of time the higher cost of service nullifies the advantage. We've had our C-Band for 6 years now, and compared to the small-dish solution we considered at that time, we made the initial hardware investment back before the first two years were up. The neighbors that got the small dishes have always wound up feeling like they got snookered.
In retrospect I do think my initial assessment was probably a bit harsh. We have people trying to sell us a small dish (for tv) all the time, and there is a kneejerk reaction that has grown out of the past 6 years experience against that, which I am afraid coloured my original post inappropriately. I certainly am not interested in the small dish television service, however if the price was right adding a small dish for internet only would make sense. We'll have to see how it compares with DSL though - the local phone company has announced DSL availability within the next month - it remains to be seen whether they can deliver. Their standard dial-up service has certainly not lead me to have high hopes.
About latency... (Score:1)
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,
Re:I can see (Score:1)
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.
Re:air broadband -- do the math (Score:1)
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.
Re:Possible reasons for the postings (Score:1)
Re:Geosynchronous orbits: 250ms latency. (Score:3)
Re:air broadband -- do the math (Score:1)
Wireless (radio) good, satellite probably not (Score:1)
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?
Mobile Computing? (Score:2)
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
Re:Geosynchronous orbits: 250ms latency. (Score:1)
This translates into a minimum roundtrip speed-of-light latency of 250ms.
Yes, but you can build a wormhole [slashdot.org] and make the signal go faster than light speed!
I can see (Score:2)
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
UK Satellite iNet access? (Score:1)
Not Enough QA (Score:2)
What if it gets cloudy? How bad a latency are we talking for a cycle?
(The RV idea is good though)
Re:Gee (Score:2)
TCP wasn't made for satellite (Score:1)
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.
Re:TCP wasn't made for satellite (Score:1)
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.
I'm curious to know what sort of equipment and service you're using to get these sorts of results.
Re:latency.. high.. packet loss.. yes.. (Score:1)
Mike
security? (Score:1)
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
Re:Possible reasons for the postings (Score:1)
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
Re:Ping times not effecting BBS!!! LAF! (Score:1)
Re:GEO 250ms latency + LandLink+ Netlink + Nic+OS (Score:1)
Did anyone else notice the "satellite" named UFO-1 flying around?
Re:OW! My Brain! (Score:1)
yeah i know half the words in here are spelled wrong, its 4am and i dont care.
Re:Geosynchronous orbits: 250ms latency. (Score:1)
Re:Latency (Score:1)
Re:air broadband (Score:1)
Where is it.... (Score:1)
-----
Whats the difference? (Score:1)
Which sounds faster? Its a marketing thing!!
Latency bad for TCP ? (Score:1)
(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.
Re:Where is it.... (Score:1)
It's the same reason why nobody wants them.
---
Where can the word be found, where can the word resound? Not here, there is not enough silence.
What about UMTS? (Score:1)
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.)
Well that sounds ok... (Score:1)
Re:Geosynchronous orbits: 478 ms light latency (Score:1)
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 [byte.com] for further discussion of TCP and latency. Also see this student article [uiowa.edu] for a discussion of alternatives.
--
Ping Times (Score:2)
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
--------
Damage Inc. BBS
dvb, mpeg, satellites, information (Score:1)
- linuxtv [linuxtv.org]
- inria.fr [inria.fr]
- dvb.org [dvb.org]
- protocol notes [tek.com]
- gilat [gilat2home.com]
- europeonline [europeonline.com]
- drdish [drdish.com]
- helius [helius.com]
- telemann.com [telemann.com]
- broadcast.philips [philips.com]
regardsRe:TCP wasn't made for satellite (Score:1)
We have developed a solution for a Swedish satellite Internet provider. It's based on fully transparent (visible for neither client nor server) TCP proxies that act as intermediates supplying the larger window sizes over the satellite link. The data rate for a TCP connection went from 20Kb/s you mentioned above to full speed (2Mbp/s) when our proxies where installed. If anyone is interested in our solution please contact me: erik.anggard@cygate.se for further information.
Erik Anggard, Cygate Sweden AB