View Full Version : Bigger, more powerful sats?
Hopper27
03-07-03, 01:41 PM
Ok, forgive the lack of sat knowledge here...
Why does Dish have to use 8 different sats in 4 or 5 different orbits?
I'm sure there is a reason, but I wonder about it cause I don't know what it is.
Why can't Dish just make a big uber sat that has lots of power and abilities and put everything in one place? If a "standard" sat has space for 100 channels, then why not make a "super-sized" sat that has space for 200 channels.
For that matter, considering how stable a sat in space seems to be, why not just put all those sats next to each other in the same orbit, spaced a few hundred feet apart, then everyone would only need a small, basic dish.
Seems so simple, and I'm sure it isn't, but I can't seem to figure it out on my own.
Thoughts?
Jason
Scott Greczkowski
03-07-03, 01:45 PM
There are only so many frequiencies in each slot that a satellite company can use.
Dish has many satellites "up there" the latest satellite is lots more powerfull then their origional satellite.
Dish has back up satellites "up there" and ready to go incase one satellite has a problem and dies.
They can't space the satellites a few hundred feet apart as they are still using the same frequencies.
I am sure someone can explain this better then me :D
Hopper27
03-07-03, 01:50 PM
Originally posted by Scott Greczkowski
[B]There are only so many frequiencies in each slot that a satellite company can use.
Why? Is that an FCC thing? If so, why doesn't the FCC just give one slot to Dish and one slot to DirectTV and let them use all the freq in each slot? As it is, they both seem to have "space" at each slot, which makes no sense. (then again, this IS the government we're talking about)
Why can't Dish and DirecTV trade slots so they make better use of them?
Dish has many satellites "up there" the latest satellite is lots more powerfull then their origional satellite.
Oh, so they do make them better? Cool!
Does that mean that they can just keep launching new sats every few years and provide more and more channels? (hopefully no more shopping channels however)
They can't space the satellites a few hundred feet apart as they are still using the same frequencies.
Another government thing? Can't they just buy the right to use other freq? Or are they all used up?
Jason
Mike123abc
03-07-03, 11:19 PM
The FCC has assigned 32 transponder frequencies to DBS transmissions. The other frequencies above and below are in use by other things like television, radio, other satellites, etc.
To use small dishes, the satellites have to be 9 degrees apart because the small dish sees all the satellites in a few degrees of the sky as a single satellite.
By international treaty the US has 61.5 which covers the eastern US, 101, 110, 119 which can cover all the US AK/HI, 148 & a couple more out west that can cover western US AK/HI. Note that other locations are used by Canada/Mexico/South America, etc.
Dish has 24 on 148, 21 on 119, 29 on 110, 11 on 61.5
Direct has 11 on 119, 3 on 110, 32 on 101
See: http://www.dbsforums.com/compare/chart.html to sell all the slot owners.
So essentially those are the only authorised frequencies that can be use for Ku band DBS in the USA.
To get more bang for the buck DBS has been using spot beams, i.e. multiple antennas to point at different areas of the country to be able to transmit different channels to different areas. This is used to deliver local in local: http://wvjw.info/dbs-beam/ .
They do not use a big uber satellite for a few reasons:
1. Current solar cell technology limits power (size of the array limited by capacities of the launch vehicle)
2. Ku band antennas are solid metal so cannot be collapsed down small, so this limits the size and number of them that can fit inside the launch vehicle.
3. It is dangerous to put all you money in a single satellite. A lot of things can go wrong. Like Echostar 3 cannot broadcast in double power without overheating, Echostar 4 which has suffered disaster after disaster and is essentially a complete loss.
Hopper27
03-07-03, 11:42 PM
Originally posted by Mike123abc
The FCC has assigned 32 transponder frequencies to DBS transmissions. The other frequencies above and below are in use by other things like television, radio, other satellites, etc.
Thanks for the great info!
Is there any chance that DBS will get more freq any time soon? TV got more for HDTV, why not do the same for DBS?
Dish has 24 on 148, 21 on 119, 29 on 110, 11 on 61.5
Direct has 11 on 119, 3 on 110, 32 on 101
Yikes, that is a mess...
No wonder they wanted to merge. Shame they won't be allowed to do so now, damm FTC!
Putting all those transponders together into a single company would allow a lot of interesting options!
So essentially those are the only authorised frequencies that can be use for Ku band DBS in the USA.
Is Ku band the only one that works for DBS?
They do not use a big uber satellite for a few reasons:
1. Current solar cell technology limits power (size of the array limited by capacities of the launch vehicle)
Why not use nuclear powered sats? That would solve the solar cell problem.
No, I don't mean nuclear reactors (for those who might be wondering), I mean the decaying heat generators that powered Voyager and Pionieer and the other NASA probes. Those function for decades without external power.
2. Ku band antennas are solid metal so cannot be collapsed down small, so this limits the size and number of them that can fit inside the launch vehicle.
You mean like the same material our little pizza dishes are made out of?
Would it simply be too expensive to have the shuttle put up much bigger sats? (isn't that what the point behind the shuttle was for?)
3. It is dangerous to put all you money in a single satellite. A lot of things can go wrong. Like Echostar 3 cannot broadcast in double power without overheating, Echostar 4 which has suffered disaster after disaster and is essentially a complete loss.
Oh, I didn't realize they lost a sat.
How much has Dish spent putting up all their sats? Sounds expensive, but given how many thousands are up there, I figure it can't cost THAT much.
Anyway, thanks for the info!
Jason
waydwolf
03-08-03, 06:30 PM
Originally posted by Hopper27
Thanks for the great info!
Is there any chance that DBS will get more freq any time soon? TV got more for HDTV, why not do the same for DBS?
Frequencies other than the 500Mhz-wide band from 12.2GHz to 12.7GHz? Not bloody likely. Here's a good idea of why:
http://www.jneuhaus.com/fccindex/3_ghz.html
They use two polarizations, either horizontal/vertical or left hand/right hand circular to give them the equivalent(almost) of 1000Mhz space.
Yikes, that is a mess...
No wonder they wanted to merge. Shame they won't be allowed to do so now, damm FTC!
Putting all those transponders together into a single company would allow a lot of interesting options!
Or a supermonopoly that would be as bad as allowing every radio station in the US to be owned by Clear Channel Communications or every cable company in the US to be owned by Adelphia.
Is Ku band the only one that works for DBS?
As far as Dish and Direct are concerned, yes. International treaties are involved with respect to satellite transmissions, and there are other users nearby on the band. Changing frequencies would mean instantly obsoleting millions of pieces of equipment between the US and Canada.
Why not use nuclear powered sats? That would solve the solar cell problem.
No, I don't mean nuclear reactors (for those who might be wondering), I mean the decaying heat generators that powered Voyager and Pionieer and the other NASA probes. Those function for decades without external power.
Because of several reasons not the least of which is that the birds don't last long enough to make it necessary(they do run down due to cosmic and solar radiation damage and micrometeroids), and that the general world population has the insane idea that any source of radiation is too much and guaranteed to cause horrific instantly fatal cancers if not giant mutant rutabegas that want to eat Toledo.
You mean like the same material our little pizza dishes are made out of?
Would it simply be too expensive to have the shuttle put up much bigger sats? (isn't that what the point behind the shuttle was for?)
The point of the shuttle was to reduce costs to reach space by creating a reusable launch platform. For satellites, rockets are actually cheaper but those can't be used to fix them.
Bigger satellites can't change the technical limitations of frequnecy assignment, interference, and the resulting transponder assignment system.
Oh, I didn't realize they lost a sat.
How much has Dish spent putting up all their sats? Sounds expensive, but given how many thousands are up there, I figure it can't cost THAT much.
Anyway, thanks for the info!
Jason
Satellites cost in the many many millions of dollars and similar amounts to launch them.
bryan27
03-11-03, 09:18 AM
Originally posted by Hopper27
Is Ku band the only one that works for DBS?
Depends on what size dish you want to use.
DBS (Direct Broadcast Satellite) is just a name given to a set of frequencies. In North America they happen to be in the KU-Band in the 12.2GHz to 12.7GHz portion of the band.
The KU-Band also has DTH (Direct To Home), it's similar to DBS except the satellite owners and the channel providers aren't the same company. DTH requires dishes 24-36 inches. The DTH band in the North America is 11.7GHz to 12.2GHz
Telstar-5 is the DTH satellite with the most providers. http://www.lyngsat.com/t5.shtml
In Europe it is just the oposite. The DBS band is 11.7GHz to 12.2GHz and the DTH band is 12.2GHz to 12.7GHz.
In Asia things get really confusing and you have situations where DBS is anyones guess. The DBS band for Indonesia is in the S-Band group of frequencies (2.5 to 2.6GHz) and reception is on a 20 inch dish.
However, it is possible for the DBS providers to use other parts of the KU-Band. E* uses a transmponder on the DTH satellite Telestar-7 for locals in Philadelphia.
Is Ku band the only one that works for DBS?It is the only one that works today for 18" dishes. Of course, others are available if you want to use significantly larger dishes...
Ka is another band that can potentially be used by 18-22" DBS service in the future. It is not currently known whether Ka-band can deliver acceptable small-dish service, but that is something DISH intends to test using a single transponder on a upcoming satellite. If those tests are successful, DISH may look to build future Ka band satellites to deliver programming and Internet service. Their Ka-band slot is at 121 degrees, so it could potentially be received using a single dish comparable in size to the Dish500.
The real issue with Ka band is rain fade. Rain fade is at least 10 times as great for Ka. With current satellite technology, even the least bit inclement weather (a cloudy day?) would result in total loss of signal. So even if DISH finds Ka service is possible in their tests, it will still require substantially more powerful (read: more expensive) satellites. However, if its doable, the benefits may outweigh the cost. At Ka band 121 degrees, DISH is licensed for a whopping 48 transponders; moreover, each of these transponder frequencies, even when accounting for the additional error correction required, should offer 1.5x to 1.7x the bandwidth of existing Ku-band DBS transponders. So in effect, there are about 64 transponders of capacity available at that slot.
If (and thats a big if) DISH finds that high-power Ka-band service is feasible for DBS, it will probably be at least another six to ten years before they will be able to build a satellite of sufficient power to make use of this capacity for programming. As it will be some time before they can build such powerful satellites, some have speculated that DISH might build a smaller satellite in the interim to deliver Internet service from this location using a larger 24-32" dish. But obviously, an extra 48 (64 equivalent) transponders would really help DISH to deliver HDTV and Internet service...as it would more than double their single-dish capacity.
How much has Dish spent putting up all their sats? Sounds expensive, but given how many thousands are up there, I figure it can't cost THAT much.You don't really think DISH paid for all those satellites with their own money, do you? Ever heard of a credit card? :) Last I looked, DISH had on the order of $6 billion in debt.
DBS satellites runs $200 to $300+ million dollars, plus another $50-$100 million to launch. Afaik, DISH's existing satellites cost in the range of $250 million each to build and launch.
Chris Freeland
03-11-03, 08:30 PM
Don"t forget about the KU-FSS band, it requires a slightly larger dish then DBS. E9 also is equipped with 32 KU-FSS TP's which E* may use to combine with their 110 and 119 DBS TP's for perhaps additional locals and or HD TV channels. I suspect E* could pull this off with a slightly larger dish with 2 DBS LNB's combined with a FSS LNB for perhaps a Dish 750 for those that need it. Could Chattanooga TN, Charleston WV and Baltimore MD locals be far behind? ;)
Don"t forget about the KU-FSS band, it requires a slightly larger dish then DBS. E9 also is equipped with 32 KU-FSS TP's which E* may use to combine with their 110 and 119 DBS TP's for perhaps additional locals and or HD TV channels. I suspect E* could pull this off with a slightly larger dish with 2 DBS LNB's combined with a FSS LNB for perhaps a Dish 750 for those that need it.DTH satellite service from KU-FSS is certainly possible, seeing that is what Primestar used. But the FSS-band transponders on E*9 will only be running at 110 watts (no double power mode available), which probably means you'd need a dish around 24-30" in diameter--plus a new LNB--to receive any kind of stable/reliable signal. But more importantly, KU-FSS transponders are, by treaty, not intended for DBS service.
According to DISH's previously announced/filed plans for E*9, the FSS transponders on E*9 will be used for 2-way business communications and to backhaul locals. The latest Echostar IX press release, issued March 11, also indicates:The satellite payload also includes 32 Ku-Band fixed satellite services (FSS) transponders, at approximately 120 watts, that will enhance EchoStar's current U.S. DISH Network satellite TV service, including additional service for Alaska and Hawaii.Interesting....I understand that a number of Alaska/Hawaii customers are already using 1 meter and larger dishes, so perhaps it's not such a big leap to serve them with FSS.
bryan27
03-12-03, 09:10 AM
KU-FSS transponders are, by treaty, not intended for DBS service.
However, they can be used for DTH service. There isn't much difference between a DTH service and a DBS service.
vBulletin® v3.7.6, Copyright ©2000-2012, Jelsoft Enterprises Ltd.