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Television Media

Broadcasting Double Signals 52

Posted by michael from the transmitting-out-of-both-sides-of-their-mouths dept.
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.
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Broadcasting Double Signals More

Broadcasting Double Signals

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  • Re:and isn't HDTV analog? (Score:1)

    by Anonymous Coward
    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.

  • 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.
  • What you're saying is perfect common sense, and I couldn't agree more. But so what? Read this paragraph from the article:

    "Among the many battles over bandwidth that have captivated Washington's lobbyists and policy makers, the Northpoint fight is particularly notable. The company has spent more than $10 million in lobbying and legal costs, and its opponents have spent considerably more. Both sides have raised large sums for campaign contributions in an effort to influence important lawmakers." [italics added]

    Unfortunately for the American people, their political system is so corrupted by money that the newspaper of record can print a statement like the above as a bald statement of fact, and no one bats an eye. Likewise for leased spectrum: it's the best thing for everyone except the ones who can afford to make sure it doesn't happen. Common sense has precious little to do with the outcome in such a case.
  • 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.
  • 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 :(
  • Won't the analog HDTV standrad be obsolesced in a few years by the inevitable digital/internet TV?

  • This will not work well (Score:3)

    by Argyle ( 25623 ) on Sunday April 08, 2001 @09:52AM (#307243) Homepage Journal
    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.
    -----

  • The patents (Score:3)

    by SMITHEE ( 26773 ) on Sunday April 08, 2001 @01:40PM (#307244)
    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 [delphion.com] 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.
  • 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.

    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.

  • It is important to note that this was imposed on them by local affiliates and the networks.

    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*...

  • 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.
  • Yay, finally someone who has a clue about radio propogation is posting! Not only do reflections make things interesting, you can't design a completely unidirectional antenna (sending or receiving); NP's south pointing transmitting antennas will leak to the north and enter other user's south pointing TV antennae, and the main signal will leak through the guard on the back of other's south pointing antennae and also create noise.
  • 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.

  • I meant multipath. duh.
  • As soon as little kids can build crystal wireless internet sets, and us bigger kids can build wireless regenerative internet sets and wirless superheterodyne internet sets, then I'll agree.

    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.

  • Why not just forget doing all this and give the TV/Radio bands up for wireless internet?
    Bandwidth. TV/Radio is broadcast, so about 100kHz of spectrum will serve up FM stereo music to everyone who wants to listen; "Internet" is point to point so each listener needs about 30kbps additional bandwidth. IP Multicast will help if it actually can get widely deployed.

    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.)

    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.
    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

  • 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?
    --
  • "Why not...?" Greed.

    -HobophobE
  • 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.

  • TV/Radio via Internet (Score:3)

    by mini me ( 132455 ) on Sunday April 08, 2001 @09:26AM (#307256)
    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
    Cav Pilot's Reference Page [cavalrypilot.com]
  • .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
    Cav Pilot's Reference Page [cavalrypilot.com]
  • 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. Further, Northpoint is trying to claim this technology for use in "rural" areas .... 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.

    I was waiting for the comment on those who lived NORTH of the transmitters. The whole thing seems fishy to me. (And patents? on what? I can't think of any patents on this other than possibly things like very specific directional antennas, yet that limits reception possibilities. And if it's dispersion of the signal, then you hit the interference situation.) The guy forgot something with that 'the lightbulb doesn't block out the start'. What he forgot was that it if you add a few more lightbulbs, it DOES block the stars.. and stars have a little more power than your average satellite at 24000+ miles. Interesting they have a 'give us free spectrum or we take our patents (our ball) and won't let anyone else play'. There should be competing services in the same type of service... even if it would be something like cable, where franshises are determined by a city. (Not that I like that, but at least there's more than one operator.) I'd say let them take their ball and run, OR make them completely liable for any interference + damages. (Since it doesn't seem to be tested yet?) Amazing something they think is so valuable, yet they demand free spectrum. hmm.

  • 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!
  • "Broadcasting Double Signals"

    Is this really anything new? Women have been doing it for years.

  • Shared use of spectrum is already happening. Where did you think the spectrum for those 802.11a systems in the 5 to 6GHz band comes from. These same bands are already occupied by C-band satellite services....

    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

  • Won't the analog HDTV standrad be obsolesced in a few years by the inevitable digital/internet TV?
    To second the AC: No, because ATSC is a digital standard.
  • Don't tv stations already broadcast using local transmitters directly to antennas at people's houses -- for free?
  • Frequency hopping schemes still fall under Shannons law. Spread spectrum fall under Shannons law. All wireless transmissions fall under Shannons law. There is no free lunch.
  • wasn't the original intention of systems like RDP, DHCP, et al supposed to dramatically reduce, or completely simplify, internet management? If executed properly, "the internet" requires surprisingly little maintenance. It's the services connected to this network that need the push (email, web, etc). The push here is for the infrastructure.

    Imagine a neighborhood where each house had a low gain antenna strapped to an 802.11b base station/router. Assuming they were properly configured, it would be an academic exercise to turn this neighborhood into the gamefest/open library seen in most college dorms. Kinda like the early days of the internet, sharing a little bit of a resource you have with the community. The difference with wireless is that, as long as most people play nicely, it's quite inexpensive.

  • Mr. Tawil observed that a porch light behind him did not obscure the twinkling stars overhead.

    Chuckle. My first thought was: Many people already believe this, and that's why we have so much light pollution [skypub.com].


  • 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

    • eliminate the scarcity of broadcasting channels,
    • allow wider diversity in programming,
    • sound better,
    • and the radios could be made much more cheaply too.

    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.
  • makes you wonder how we ever made it to color TV, doesn't it?

    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.

  • 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.
  • Your likely to get a crappy picture...
    small transmitters on towers could offer a competing and far cheaper service by beaming signals on the same frequencies from the north of their intended subscribers.
    Doesn't certain factors come into play where a signal can easily get obscured from the sender to the recipient, e.g. a tower in Manhattan N.Y.C., wouldn't be the correct solution since its visibilty (signal wise) wouldn't get through at all points unless you created a mesh of interconnecting towers to constantly (rount robbinishly) distribute the signal, and its still not guaranteed.

    Signals travel in a straight line, so those from towers have a limited range on the curved surface of the Earth. But that smaller range would make it easier to offer the local programming that has eluded satellite services, which by their nature broadcast to huge areas.


    And because such a system would not require launching satellites or laying cable, it could be offered at a fraction of what is being charged by direct broadcast satellite and cable television services, in rural as well as urban areas.
    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.

    U.S. versus Japan [antioffline.com] (secret showdown)
  • Read the article. Both a Bush, and a relative of Vernon Jordan are involved. Politics makes things happen
  • I think part of the problem is this:

    If the licenses at issue are put up for competitive bids, Northpoint executives say they will walk away from the market, taking with them the patents that they say protect the only known technology for offering a new alternative to subscription television.

    So these guys want the gov't to give them the frequencies (for the greater good of mankind, of course), and if that doesn't come to pass, Northpoint'll just take its ball and go home. I'm curious what exactly in these patents is so valuable (and who do they 'protect' the technology from, exactly?)

  • Better yet, we can just give the spectrum away:

    If the licenses at issue are put up for competitive bids, Northpoint executives say they will walk away from the market, taking with them the patents that they say protect the only known technology for offering a new alternative to subscription television.

  • 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."
  • heyyy we like, we could even have the sucessor to geeks in space... Slashdot TV!
  • "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!
  • 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 [www.news.d...8pagealpha] or a babelfish translation here [port5.com].

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