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Broadcasting Double Signals
Alan Stovall writes: "The New York Times has a story on broadcasting television (radio etc) signals over the same frequency as satellite services hence doubling the available spectrum. This could have an incredible impact on the broadcast medium." It could, but as the article details, the incumbents are busy quashing it.
No. The ATSC system that is being phased in now is digital. It's basicly a digital transport stream that can carry anything. I believe it's around 20Mbps in a 6Mhz slot of spectrum.
http://channel.nytimes.com/2001/04/08/technology/0 8SPEC.html?pagewanted=all
As the satellite's signals aren't very strong by the time they arrive here, it won't take much to interfere with it. Even if Northpoint is using a dish to beam its signal to each individual customer, there *will* be objects that will reflect some of the signal, at odd and unpredictable angles.
Correct. And "minimal" interference will translate to a 100% picture loss for people who already have a marginal signal or during heavy rain. There are 10's of millions of satellite subscribers in the US. Northpoint wants to step in and interfere with their service? And grab the frequencies for free? What a deal!
Disclaimer : I work for Echostar.
2. Impose some sort of regional limitations, a la DVD. Actually, DirecTV (and other DBS providers) do this already - local stations are blocked based on where they know you to be.
It is important to note that this was imposed on them by local affiliates and the networks. Before that, you got one affiliate on the east coast and one on the west coast for each network. It took a federal judje to turn that simple (and preferable) approach into the hash it is now.
DX'ing TV requires more expensive equipment to find the results as rewarding, but it too is done.
Like a flyback transformer? Amazing how just one transformer acts as the horizontal trace, generates both the high voltage and low voltage power supplies, and syncs the picture. Television electronics is innovative (used to be a good word) when it comes to simplicity.
Building a wireless internet, like building a television should be a good lab project for high school science students.
Whether the technology behind this particular scheme is workable or not, it illustrates the stupidity of auctioning spectrum instead of leasing it. You never know when another, perhaps better use for a particular chunk of spectrum is going to come along, including uses that benefit the public without providing an opportunity for some business to make a profit, so that the government will need to reclaim that particular chunk of bandwidth. If it's leased, it's a lot less of a problem than having to institute condemnation proceedings in an area (unreal estate?) where that concept has never existed before.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
As the article points out, in America, the dish antennas all point south. Now, unless this new service is using a huge array of dish antennas themselves, to aim their signal at only people who live south of them, that means that their signal will be in sight of anybody *north* of them.
As the satellite's signals aren't very strong by the time they arrive here, it won't take much to interfere with it. Even if Northpoint is using a dish to beam its signal to each individual customer, there *will* be objects that will reflect some of the signal, at odd and unpredictable angles.
Further, Northpoint is trying to claim this technology for use in "rural" areas. Um, hello? In rural areas, there are not *that* many people within line-of-sight of the antenna (and believe me, at frequencies as high as they're using, it's *all* line-of-sight).
I've been in HAM radio for about ten years now, working mostly at VHF, UHF and microwave frequencies, and I have *never* heard such a load of rubbish as this. While I'm not fond of the Powers That Be, they're right - Northpoint *is* trying to make a naked grab for their chunk of the spectrum.
Don't waste your money buying their stock.
Lemon curry?
Yup, spread spectrum might well work. I've recently seen it being done on cordless phones, so they do have a form that'll work for microwave-range signals (the spread spectrum stuff is in the 900MHz range, near microwaves).
:(
To other users of that frequency, it'll look like the noise floor is a bit higher. This may be an issue to satellite TV broadcasters - if the local noise floor gets too high, it will degrade their signal
Lemon curry?
Won't the analog HDTV standrad be obsolesced in a few years by the inevitable digital/internet TV?
cpeterso
The terrestrial broadcast will interefere with the satellite transmissions. I happen to have a large earth station with three 9 meter, a 7 meter, and a half dozen TVRO dishes. We get terrestrial interference all the time from a variety of sources. Northpoint's plan will cause nothing but trouble.
Professional broadcasters go to great lengths to ensure that they are not interfering with the frequencies of others. Coordination of these frequencies is difficult and time consuming.
Intentionally broadcasting on the same frequency is simply idiotic. Northpoint is looking for the easy way to get some spectrum and they are attempting to muscle their way into some free space.
If people want bandwidth they should look at the TV broadcasters. Currently they are each allocated TWO channels due to this insane HDTV fiasco. Settle the HDTV issues and you will have plenty of bandwidth to spare.
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As yet, no one seems to have commented on another Slashdot hotbutton issue here: patenting the obvious. Northpoint claims to have a bunch of relevant patents. The main patent seems to be basically for the "business method" of using directional antennas while hopefully keeping the transmitter power low enough that interference is negligible. If so, that is worse than the "one-click shopping" patents.
I really hate to sound overly cynical, but... I suspect that if this were ever to happen, the 'content' owners would:
1. Ensure that the content was only accessable by 'authorised' clients. Think SDMI, but for all of the content that used to be broadcast/satellite
2. Impose some sort of regional limitations, a la DVD. Actually, DirecTV (and other DBS providers) do this already - local stations are blocked based on where they know you to be.
3. Formally put an end to any notion of fair-use. Everything is pay-per-view.
In short, yes, I think it could be done, but I don't want the current 'content' owners to do it. Never mind that 98% of what's on commercial tv and radio is utter crap anyway.
Where the value of X-Mailer: is the true measure of a man...
True enough, but as I said, it would be the content owners' imposing this control. I remember the days before this decision came down - you could get NBC,CBS,ABC,FOX and PBS off the bird for $5/per month. It was sweet. I don't think that DirecTV would have ever done this without the serious arm-twisting the corporate network overlords initiated through the court system, on my (as an American taxpayer) dime. I think they were just happy to get paid. Now they have to chew up all kinds of bandwidth carring duplicate content, all in the name of protecting the advertisers' revenue stream. Bandwith that I'm certain could have been put to better use. *sigh*...
Where the value of X-Mailer: is the true measure of a man...
I disagree; Internet equipment is much more expensive than TVs, and it requires a monthly fee (because it's about maintaining infrastructure). Furthermore, whoever gets the license for that spectrum is gonna charge insane amounts (look at the guard bands that the FCC has recently auctioned off for hundreds of millions of bucks... junk bandwidth). If you don't license the spectrum, and use it for ISM, range is limited, and it's not of benefit to the people living out on the edge of a city. Sounds great for geeks who are T3 connected and have a data-capable cell phone, but 80% of the general population would get screwed.
Doesn't this work on the assumption that these signals are line-of-sight and don't reflect?
My satellite dish is mounted on the balcony of my apartment and shoots south. However my line of site shoots over a bunch of buildings/trees/etc that could swamp my dish if a signal from the north reflected into my dish. I would assume the terrestrial signals would be much stronger than the satellite signal overhead and could swamp my reception.
Radio is a wonderful hobby. Don't screw up a good thing- anyone with a wire, a coil, and a capacitor can get a signal. Through in an amplifier? You can get signals from around the world. DX'ing TV requires more expensive equipment to find the results as rewarding, but it too is done.
-bugg
The VHF spectrum just doesn't have a lot of bandwidth. If we throw all users off VHF, there's probably a few hundreds of Mbps of data bandwidth. (As a very coarse zeroth-order approximation, max. data-rate is roughly equal to the frequency of the carrier. VHF is 30MHz to 300MHz.)
And carrying TV will require around 1-4 Mbps of bandwidth (depending on the codec) for each video stream. If all the people currently watching broadcast TV switch to watching IP streams... well, let's just say that we won't have that sort of bandwidth for a few years.
Sure there's a lot of tech dreaming and hand-waving about spread-spectrum and all that. Just remember: TANSTAAFL. If you have a certain amount of spectrum available and a certain level of background noise, there is an absolute limit on how many bits you can cram through. Read Shannon's work. (That man was a genius.)
Let's say you settle for MPEG-1 (quarter screen TV). You want to pay for 1 Mbps of upstream bandwidth for each viewer of your TV station? (Widespread multicast is a long way off.)-s
Unlimited growth == Cancer.
Wouldn't you need all new reciving equipment to get the extra channels/frequencies. And how would old radios/tvs react to the doubled up frequencies?
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It's not a matter of technical limitations.
It's all leagal.
The radio spectrum has been spread apart for various different uses; most often using some frequency ranges to fit a specific task that the frequency is suited for. Unlike most popular opinion, radio waves behave *very* differently at different wavelengths. What might be fine for TV and radio is near useless for networking. Some frequencies are line-of-sight only, while others follow the curve of the earth. Still others bounce off the ionosphere.
Most importantly - anything metallic can receive these radio transmissions. Nearly all of the leagal issues with starting a radio station have to do with being 100% sure that there is no interference with other frequencies/bands. The expertise required to achieve this is *so* far beyond what 'anyone' can do that nobody can start their own little station.
The laws on the books (In the U.S) state that any kind of transmitter has to meet certain criteria. For non-Ham/Ameteur radio operators, this includes that the transmitter must pass FCC certifications for the specific frequencies that the device uses. These devices cannot be modified or serviced in any way; if you want to change frequency, etc, you have to send the thing back to the factory. Home-built gear has to either operate on Ham frequencies, or be at such low power levels that the range is less than a few feet.
And even then, consumer goods can only use a very small wedge of the frequency - and the reasons are more than clear: The consumer radio spectrum is cluttered, unregulated, and very low power.
The high-power, high-range commercial frequencies (and the Ham frequencies) both require FCC licenced operators and equipment. (Although Hams get a huge amount of leeway as long as they use the Ham radio frequencies)
The idea of 'home' internet radio stations using wireless internet is crazy. The amount of regulation is too high, and is all-too necessary to actually have the idea work.
Besides: the broadcast TV/Radio bands are a *really* small part of the radio spectrum. If you want more radio/tv stations, try working on technologies to transmit the informatino in a smaller bandwidth.
Yes... radio bandwidth has to deal with both the frequency of the radio wave, as well as the amount of data it can carry. Want to have 100Mbps wireless ethernet? Fine... but it will take up a huge amount of frequency bandwidth to achieve that kind of data throughput.
People who don't understand just how difficult it is to get wireless technologies to work without interference of others shouldn't be advocating wireless at all.
There are much more Cable channels than broadcast... the reason is because there isn't enough bandwidth to carry the number of channels cable has over the airwaves.
-- Sometimes you have to turn the lights off in order to see.
Why not just forget doing all this and give the TV/Radio bands up for wireless internet? Then the TV and radio stations can use the internet to broadcast thier content. This would enable us to get tv and radio from anywhere in the world and not being confined to our distance from the station or what stations our cable/satalite provider offers. Another benifit of this would be that it would allow anyone to start thier own station with little more than a camera, computer and net access. This could lead to bringing us quality programming (not likely, but it's a nice theory and it's not like it can be worse than what is already on tv and the radio!)
I still long for the day when I can tune into any station in the world from my car over the internet or watch a television broadcast from the other side of the world. Oh and while we're at it, why do we have to see all these stupid on screen displays such as in the case of sports the scores in the corner of the screen. Why I can't I bring that info. up on demand instead of being forced to watch it throughout the entire show?
I'm sure there are some techincal limitations as it stands right now, but if we freed up these bands would wireless broadband be possible? I sure hope so.
Why don't we use freq hopping technology to transmit quite a bit? With Sincgars freqhopping a couple hundred times a second, the people on any of the fixed channels it's using have no idea the hoppers are using that freq. With a nearly unlimited number of frequencies to start on, using 100 freqs to hop for one channel and an almost unlimited salt, it would be a very, VERY long time before we ran out of possibilities before we ran out of broadcasters who wanted to put anything out there for the public.
DanH
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.jpg files with hundreds of byte text messages within them. Top Secret documents over the open internet tunnelled within normal connections over the 'net. I'm not sure this is so new or newsworthy as to warrant the title of news.
DanH
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Save the telecom act of '96, lots of our current regulations are based off of the original 1934 act (which was based on the Radio act of some years before). I agree that the laws are dated; however, the FCC has done a fairly good job of updating its Titles/Sections to handle new technologies (cable, for example).
A change in the spectrum layout may increase efficiency, but requires lots of time, effort, and money to make sure the least number of parties are negatively affected as a result.
Don't forget the lobbyists!
Is this really anything new? Women have been doing it for years.
The key here is that the secondary service is in no way allowed to interfere with the primary service. Hence, there are strict limitations of the way these bands are used. I.E. 23 dBm maximum transmit power for 802.11a in the 5.18 to 5.29GHz band. David
Don't tv stations already broadcast using local transmitters directly to antennas at people's houses -- for free?
In Europe and Asia broadcasters are using spread-spectrum techniques to broadcast, using much less bandwidth (hence more channels are available) and resulting in a better system all around.
How come we don't have that here?
It could
By the most conservative estimates, they could quadruple the number of channels available using the existing spectrum. This is actually *quite* conservative, many people think digital radio could easily increase the number of channels available by a factor of 10 or more..
For example, in the bandwidth taken by just *one* current TV channel, you could fit five times the number of FM stations that exist on the whole FM band now. (And interference would be completely eliminated.)
Plus, the equipment to set up a digital broadcasting station is much cheaper than what is required for old-fashioned analog broadcasting. This would make it affordable to churches, community groups, music lovers, and hometown sports teams.
What's going on in Washington? How come the Europeans and Asians have digital radio and we don't?
This means that without paying money you can get a lot of channels with your antenna. And they want to stop this because, duh, you won't have to pay for cable; Just a fancy antenna which is rather in expensive. How come all the good things are squashed while all kinds of evil things out there are ok. Get your priorities straight everyone.
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Actually, that's pretty simple. The color signal took no more bandwidth and was 100% compatible with the old B&W receivers. Broadcasters needed no extra bandwidth to add a signal which would not drive away their old customers, but which would attract the new customers who sprung for color TV sets.
By contrast, HDTV requires a totally new infrastructure of camera, recording, editing, and broadcasting equipment which is not compatible with the 300,000,000 or so existing TV sets. Bear in mind that amplifiers and editing equipment built for B&W will generally work with color, but nothing built for standard TV will work with HDTV. And HDTV only works for standard signals if it is essentially "dual mode," much more of a leap than the added expense of designing color circuitry into what was originally a B&W design.
There is also a much larger infrastructure of this more incompatible equipment than there was during the adoption of color. Someone has to toss out the first dollar and so far neither the producers, broadcasters, nor public have been willing to take the risk that they will be caught holding the next generation's version of a Beta VCR.
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No, a porch light won't obscure the stars overhead... But use a modulated porch-light to send a signal to a light sensor. As you move away from the porch, its light becomes more and more drowned out by the light from the stars. This basically means that the fringe reception area for TV stations suddenly becomes much, much smaller, and a lot of people on the outskirts of town are suddenly forced to get satellite dishes; or at least a special defocused antenna to try and get more signal strength from over thataway ------->
Pondering the subject some more, I realized I'd made two wrong assumptions...
1. The signals used would be analog in nature, and
2. The bands used would be VHF and UHF.
The fact is, this technology isn't well-suited to broadcasting over the old TV bands; the receiving antennas required would be large and ungainly, and the transmitting antennas might be completely impractical, depending on the amount of directionality you wanted. Satellite broadcasting is better done 'round the microwave region.
This means a directionally-sourced satellite signal would work best on a system much like the one HDTV will soon be broadcast on. It also means people still stuck in fringe areas for VHF/UHF won't be affected (at least, not until the networks give up the old bandwidth).
As for the fringe areas for the new ground-station broadcasters, because of the nature of digital transmissions the "fringe area" where the signal strength goes from effective to obscured is much smaller than the fringe area on an analog footprint. Adding more noise from satellites overhead would reduce that footprint, but many fewer people would be affected than if this were tried with analog.
Whats the purpose of selling something if there's likely to be issues somewhere down the line via way of quality. I understand its a nice idea, shit I would like to see it take flight just because its a new concept, but arguably, its no better than digital satellite reception, the clarity, etc., its only saving you a few bucks... Wait I take that back, since its local programming, its not like your paying for it anyway, so this wouldn't neccessarily affect the avg person, unless their paying to watch local tv via sattelites without getting cable access.
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Read the article. Both a Bush, and a relative of Vernon Jordan are involved. Politics makes things happen
You mean it looks as good as free to air PAL?
I think we can safely expect the networks to do exactly what they did with HDTV bandwith--grab it, because it's valuable, and then do nothing with it, because there's no motivation until people can receive the new signal. Meanwhile, people won't buy the new equipment until there's a signal to receive...makes you wonder how we ever made it to color TV, doesn't it?
Yes, I know that there are some stations out there broadcasting in HDTV, but they sure took their own sweet time about it, didn't they?
"Thinking is not a right, it's an obligation."
"Mr. Tawil observed that a porch light behind him did not obscure the twinkling stars overhead." - Isn't this is what light polution is about, the reason I can barely see the stars from where I live. And my friend living out in the country has a wounderful view of the night sky? Any way they'll probably prove in a few years time satalite tv gives us cancer... doh!
~www.devnull.co.uk
You have WAY too much free time. And I have no mod points today, its a shame realy.
They tried bring this one in over in Germany about two years ago, but the cable companies wouldn't be having any of it. An article can be found here or a babelfish translation here.