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Australia's Outback Could Get Web Via TV Antenna
disco_tracy writes "Australia began switching off its analog TV signals in June and the transition to digital-only transmission is expected to be complete by the end of 2013, five years before the roll out finishes for the NBN. The leftover analog spectrum could be used to deliver Internet to people living in remote areas. Unlike 3G networks, which lose download speed with more users, the analog signal would provide a consistent speed no matter how many users there were."
Unlike 3G networks, which lose download speed with more users, the analog signal would provide a consistent speed no matter how many users there were.
Gentlemen, I think we've found our solution. With 4G, we need to first convert the digital signal to analog before transmission. Network congestion will be a thing of the past!
Yes, but Australia's outback cannot get uncensored and unsupervised web via TV Antenna.
The article talks about sending internet access over an analog signal. I think the article writer was a bit off. More likely they're just using the bandwidth formerly used for analog TV, repurposing it to digital wireless broadband. I wish that happened here in the US. The whole comment about the number of users not mattering must be bupkus.
There can be any number of users, but they all have to be looking at the same part of the internet.
awesome, because i had such a quality TV signal in the City! it could surely only be BETTER for those people way out whoop-whoop.
I wouldn't want anyone to tune into most of the things I watch.
Unless you're into that/those sort of thing(s).
There is no digital.
The is only analog.
You can define Vcc as true and 0 as false, but analog they remain.
There is certainly no digital RF anything.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
why is it the goal of technology missionaries to deliver the lamosity of facebook to some dude in a shack in the middle of nowhere? Like a neutered dog, i just don't get it... unless it's religion in which case I do get it, but still don't
When you click "Private Browsing" the screen goes blank for everyone else unless they can guess the URL you are looking at.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
I don't have time for a full writeup, but read for some reasonable info. This is intended for areas where the user density is very low, so low that the users are at significantly different angles from the base station, and multiple steered beams can be sent to different users at the same time. They can get about a 6x gain in capacity that way.
The "reuse of analog" simply means that existing VHF antennas at the user end will work. This is useful, because in remote areas, people already have big towers with fixed antennas pointing in the right direction. The base station antennas change drastically, the modulation scheme changes, the user interface boxes are new. Only the user end antennas remain. But that's the item that's a pain to replace in the field.
The guy behind this is a serious RF guy, worth listening to. He can probably make this work.
(Disclaimer, I work for a broadcaster in Australia, so take this with a grain of salt)
OK for starters the bit about "consistent speed no matter how many users there were" is complete garbage, with ANY radio based system data system.
Secondly, if you start using the TV spectrum for data in both directions, you start putting a really strong signal OUT your TV antenna, which despite being on a different frequency to the actual TV channels, it is close enough to swamp the (really weak by several orders of magnitude) TV signal on the next band with the (extremely strong in comparison) outgoing signal.
So you can forget about watching TV while you're using the internet.
The decision to sell the TV bandwidth rather than just keep it for the public use (eg. super HD TV, or super multichanneling or whatever is in the future) is completely about $$$$ and greed by the Federal Govt so they can sell the bandwidth to the highest bidder.
Grrr.
I'm a perfectionist but I'm trying to cut back.
The ability to transmit VHF (TV) into the hinterlands had as much to do with multi-kilowatt signals as it did with frequency. Pump 60 Kw into a 2.4 GHz wifi transmitter with a good directional antenna placed on a high tower and I'll bet the punters in the outback can find a working hotspot -- probably one in China at that power.
Learning HOW to think is more important than learning WHAT to think.
The whole comment about the number of users not mattering must be bupkus.
Not really. We're talking here about a system which directionally targets the signal to the endpoint. It's not like mobile phones where you all share the same bit of bandwidth of the base station. It's a case here of there's an antennae on the base station dedicated to you, another to your neighbour, both with the same bit of bandwidth but don't cross the streams. Well not quite but you get the idea.
The reason this works is because the technology is aimed at stupidly sparse populations. It wouldn't work in a city, heck I doubt it would work in a small town.
Censorship for All!
Although I am posting AC because this computer doesn't have my account posting this is a dupe.
http://mobile.slashdot.org/article.pl?sid=10/11/03/164217
The CSIRO have a way to send thousands of very low bit rate (like 5 baud) adaptive channels as one pipe with a huge bandwidth, with the vast bandwidth of a TV channel becoming free they can both send and recieve a broadband signal.
Think 5W CB radio from one state over with full error correction.
This article is a good example of how little journalists know about the subjects that they write about. How much bullshit are we being fed when we read about fields that we know nothing about ourselves?
-- Even if a god did exist, why the fsck should I worship it?
Just a minor hiccup there: How are you going to get all Aussie rednecks to browse the same internet pages at the same time?
Excuse me, but please get off my Pennisetum Clandestinum, eh!
Hello... lest we forget this is from CSIRO!
PATENT TROLLS!
No thanks.
Don't care how great an idea it is, if it even leaves AUS, its from CSIRO and thus should be shunned for their patent trolling ways.
1311393600 - Back to Black
This is possible by using several directional antennas or an antenna system of at least 4 ( or more ) antennas which get a phase shifted signal to cancel out in one direction and to amplify in another one.
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This has nothing to do with analog or digital. Nyquist ist still valid
It's a case here of there's an antennae on the base station dedicated to you, another to your neighbour, both with the same bit of bandwidth but don't cross the streams. Well not quite but you get the idea.
Because having a UHF transmitter for each user is going to be amazingly cost-effective.
Precisely. Something like 97% of Australia's population can receive Internet via more conventional means: fibre/cable/dsl in cities and towns, and 3G for 'rural, but not stupidly remote'. This technology is aimed at the remaining 3% who have no means of getting the Internet at all except via satellite. The truly remote. Those whose nearest neighbour is 200 km away and own cattle stations larger than some US states. The kind of people who aren't even connected to the electricity grid but rather generate their own power via generators/solar.
The tech has very major limitations, but for the purpose it's aimed at, it should work very well. At the moment these people rely on satellite, which while OK in terms of throughput, has awful latency.
I suspect the GP was engaging in a bit of hyperbole with the "China" reference, but reception of Chinese VHF TV signals in Australia is in fact possible on rare occasions via the ionosphere. The propagation modes usually involve simple refraction from the E layer or F layer, although occasionally more exotic types of propagation, such as trans-equatorial propagation ("TEP"), occur. However, these all fall into the category of anomalous propagation, occurring for a few hours per month or year and, while interesting phenomena in their own right, aren't suitable on which to base one's daily Internet service.
It is also true that ionospheric propagation of 2.4 GHz signals is unknown. However...
There are propagation modes that favor the higher frequencies over the lower ones. Tropospheric propagation, for example, is much more effective at 2.4 GHz than it is at VHF, and can occur at all parts of the sunspot cycle, since it depends on weather conditions instead of the ionosphere. For example, Table 2.1 in this article shows propagation from California to Hawaii on 2304, 3456, and even 5760 MHz via a well-known tropospheric duct. (See also this discussion on the relevance to trans-Australia propagation.) Paths in excess of 6000 km (Western Australia to Reunion Island, off the east coast of Africa) have been reported. But again, this is anomalous propagation, unsuitable for daily Internet service.
The GP has a point about transmitted power. VHF TV broadcast stations have effective radiated powers ("ERPs", defined as their transmitted powers multiplied by their antenna gains) measured in the hundreds of thousands to millions of watts, as well as high antenna sites (on towers), so it's a bit unfair to compare VHF TV reception ranges to those of 2.4 GHz Wi-Fi systems.
The main advantage of the proposed system is that the users, in remote sheep stations, won't have to replace their existing VHF TV antennas, which would otherwise be a significant financial investment (and that the system would be point-to-point, rather than point-to-multipoint, which enables frequency reuse without loss of bandwidth). Were this not the case, it would be clear to most RF system designers that a microwave system would be superior to the VHF system. Not only is more bandwidth typically available (remember, there are no competing services in the outback), but a 2.4-GHz antenna the same physical size (strictly speaking, having the same effective area) as the VHF TV antenna would have substantially more gain: The gain of a parabolic dish goes up as the square of the operating frequency. Operating an antenna at 2.4 GHz instead of, say, 60 MHz (in the VHF TV band) would result in a gain increase of 1600, or 32 dB. If it had 18 dB of gain at VHF (a pretty decent TV antenna), it would now be 50 dB at 2.4 GHz. (This is why point-to-point microwave systems were used before they were overtaken in the bandwidth race by optical fiber.) This additional 32 dB of gain would greatly increase the range of the 2.4 GHz system over the VHF system, and would be available all the time -- making for a suitable Internet connection. In fact,
The problem with that idea is that, yeah, the person in the hinterlands can hear the tower, but the tower most likely can't hear the response back from that person. The Internet depends on two-way communications. I suppose you could do something like the early satellite internet, where it uses a dialup modem for the 'upstream' bandwidth, and uses the RF signal for the highspeed 'download'. That's a very limiting model, but is better than dialup both directions, I suppose.
I mean, how it is *remotely possible* that an article with only 1 technical fact (TV frequencies can be used for long-distance communication relatively cheaply), and a bunch of complete *bullshit* (High Speed Internet a "basic human right", Internet as an analog signal, no decrease in speed with increase in users), make it through the editorial screening for the "News For Nerds" site, but I *know* that other articles with much greater merit get completely ignored?
No, I'm not new here, but man, it's like they just don't give a shit about *pretending* to give a shit about doing their job anymore.
I don't see why it shouldn't be. Despite the "ultra" in the name UHF isn't all that high frequency by modern standards and by using very directional.
The real question is how directional can you make the antennas before the antennas themselves become insanely expensive. Line of sight is also important.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
I don't see why it shouldn't be. Despite the "ultra" in the name UHF isn't all that high frequency by modern standards and by using very directional.
That should have said and by using very directional antennas it should be possible to keep the transmit power low.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
Analog tv broadcast of internet would require something that doesnt need perfect transmission the first time, and packets can be retransmitted with error checking and checksums.
I bet companies like blizzard would LOVE to be able transmit the 15.6gb WOW:cata client at 100 mbps. Also microsoft windows service packs and linux ISO's...things that can be pieced together.
Those whose nearest neighbor is 200 km away and own cattle stations larger than some US states. The kind of people who aren't even connected to the electricity grid but rather generate their own power via generators/solar.
Shouldn't that "kind of people" be outside minding the livestock on their Rhode Island-sized ranch, keeping an eye on the generator and watching for dingo attacks instead of updating their Facebook page?
This csiro news page http://www.csiro.au/news/Broadband-coming-wirelessly-to-the-bush.html talks about how efficient the tech is. "CSIRO is achieving spectral efficiency of 20 bits per second per Hertz (20 b/s/Hz)" "CSIRO’s spectral efficiency is three times that of the closest comparable technology and the data rate is more than 10 times the industry’s recently declared minimum standard."
So how does this allow the subscriber to send data? Does everyone have to have a megawatt transmitter in their home?
Analog tv broadcast of internet would require something that doesnt need perfect transmission the first time, and packets can be retransmitted with error checking and checksums.
Like TCP?
We both said a lot of things that you are going to regret.
Its not that simple. A 15.6 gb file like WOW might be transmitted serially to all receivers every half an hour (taking about 23 minutes to transmit). You might even have it transmitting on 3 different channels staggered so if you missed bits you wouldnt have to wait the entire time to get it. Also while you are downloading you can still use your regular internet connection for whatever without losing bandwidth.
Economy of scale dictates that 2.4 and 5.8GHz kit is cheaper than UHF. TV aerials aren't particularly high quality, and neither is the coax. You'd have to replace both before they were suitable for data.
"Economy of scale dictates that 2.4 and 5.8GHz kit is cheaper than UHF."
Yep, and also they have shorter ranges, thus requiring more transmission power than UHF to go further.
"TV aerials aren't particularly high quality, and neither is the coax. You'd have to replace both before they were suitable for data."
We do have these things called Radio Modems. Sure you can only get ISDN speed but you didn't have to replace a damned thing, you just plugged the modem into the antenna. I used to use one way back in the early 90s.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
Yep, and also they have shorter ranges, thus requiring more transmission power than UHF to go further.
Or a higher-gain antenna, which is easier to make and more compact at microwave frequencies than at UHF. You've also got the advantage that a high-gain antenna works just as well on receive as it does transmitting, so you can hear weaker signals as well as transmit further.
We do have these things called Radio Modems
I know. I design, build and install systems using them. They don't work with TV aerials or coax, and they (mostly) suck at UHF. They're slow (38400bps *if* you're prepared to pay about £1000 per year for a suitable licence, and *if* you can get a licence - it's called "broadband" for a reason, and huge chunks of spectrum cost). They suck.
Get Ubiquiti microwave kit instead.
You do realise that if you own land of that size, it is mostly 'remotely' managed. GPS-tagged livestock. High-res satellite imagery. Detailed weather synoptic charts and forecasts. Decent quality internet service is needed for this. It is not 1950 anymore.
Also you are implying that such people are working 24/7 and have zero relaxation time. Do you not also think that people that live and work in such places should be able to enjoy the same online entertainment options (IPTV, gaming, etc) as those living in cities? What about their spouses and children? Shouldn't they be able to communicate rapidly and effectively with the outside world (e.g. video chat with relatives living far away)?
But since we're talking economies of scale the whole point was using existing infrastructure that is being decommissioned. Suddenly replacing every end user's TV antenna raises the cost again.
Compared to what? Abandoning the end users? Installing new infrastructure? Laying 30km of new cables / fibre to reach a single household?
Of course it's expensive, but this is a solution to replace satellites to a very tiny proportion of the population likely to be subsidised by the government's national broadband network, not something that carriers will roll out in the city to make a quick buck.
Except that everyone in the world is modernising. Including customers like the supermajor grocery stores, and the transportation companies which provide goods tracking online. Not to mention the ability to file your business activity statements online beats driving 100km to the nearest town to talk to your accountant.
Not sure if you think that all there is on the internet is facebook and slashdot, or that farmers are some backwards armish people, but the last remote farm I visited had a cow milking system which put most major factories to shame complete with GPS / RFID tagged cows.
When you're on your own on a farm this size then the ultimate goal is to have the farm run itself, and technology is a definite help for this.
Exactly. It's worth considering that Sky Television (UK satellite provider) will quite cheerfully rip out a six month old installation and put a new dish up if a house has a dish left by a previous customer? Why? Because you don't know what state it's in. The cost of just replacing it and doing a new install from scratch worth less than the risk of having a shitty half-broken dish, poor performance and a dissatisfied customer. After however many years on someone's chimney, how do you know what state the TV aerial and coax are in?
We do the same. I work for a company that does radio systems for businesses. Among that, we cover two large fleets of vehicles that include security guards, road gritters and school buses. Any time I install a radio into a vehicle I take the radio out of the old one, clean it up, align it to factory spec (usually rather better, smug git that I am) and test it before refitting it - with a new aerial. Experience is a great teacher, and it teaches that if you reuse an old aerial and feeder you'll end up going back to that job.
Microwave "last-mile" stuff is cheap and effective, and works over the same sort of range we're talking about here. Bear in mind that the distances you can cover in a single hop are limited by the timing in the modem once you've got a good aerial up. Radio waves travel at the speed of light, which is surprisingly slow - about five microseconds to travel a mile. If you try to use conventional wifi cards you need to increase the timeout settings, because it takes so long for a packet to reach the far end and be replied to - in fact, Atheros cards have the facility to specify "timeout" in metres! From the distance given it calculates appropriate settings for various parameters, so it knows to expect long ack times. Think about it this way, if you live more than half an hour's drive from Pizza Hut, you're not going to get your delivery in half an hour.
Using a cheap crappy TV antenna and cheap crappy TV coax is a false economy. Rip it out and put proper stuff in.
The premise here is that the system is designed to work on fringe signals. If cheap and crappy works then why does it matter?
I can use an analogy that happened to us at work recently. Our 2-way trunked radio system has worked fine for years. Yet somehow recently an RF engineer was trying to tell me about the benefits of replacing our single 800MHz dipole with 1 dipole for the transmission, and 3 120degree directional arrays for receiving to provide more coverage. The conversation went along the lines of:
Him: It's better.
Me: Why?
Him: Better signal strength means more coverage.
Me: But we have the site covered, the signal even reaches across the river.
Him: But it's better...
And this unfortunately went on for some time. I don't expect every customer to have a 100% working system. I expect it to be tested for fit for use, just like when I get a cable modem installed the tech comes out and plugs his dobywacky in and gets a signal strength out.
Cheap crappy TV antenna and cheap crappy TV coax is not a false economy if it's fit for the purpose, and in this case the whole point of what they were doing was to make sure the old crappy gear IS fit for purpose by applying tweaks to the purpose rather than the gear.
The myth that free-space propagation loss is frequency-dependent is probably the most pervasive misunderstanding in wireless. Read the "Physical Explanation" in your own link:
Think about it: If free-space path loss increased as the square of frequency, there would be so much loss at light frequencies that we'd never see the sun!
Free-space path loss is actually just the result of the transmitted energy density decreasing on a sphere centered on the source as the radius (and, therefore, the sphere's surface area) increases. A second effect, which causes all the confusion, is often added into the definition: The type of antenna used at the receiver.
To match the isotropic source at the center of the sphere, people (including the Wikipedia author) typically, and quite reasonably, make the assumption that the receiving antenna (on the surface of the sphere) is an isotropic antenna, too. The problem is, the effective area of an isotropic antenna is inversely proportional to the square of the operating wavelength. This gives the free-space path loss equation a frequency dependency that "free-space path loss" actually doesn't have.
This belief is compounded by the types of antennas typically used in simple wireless devices. Dipole antennas, like isotropic antennas, have an effective area that is inversely proportional to the square of the operating wavelength. Think about it: A dipole resonant at 60 MHz is 40 times longer than a dipole resonant at 2400 MHz, so its effective area is 1600 times greater. If one just swaps antennas it's going to look like the received 2400 MHz signal is 1/1600 that of the 60 MHz signal, due to "increased path loss" at the higher frequency, when really it's just that the 2400 MHz antenna is smaller.
Pleasantly, not all antennas have an effective area that is inversely proportional to the square of the operating wavelength. Parabolic dishes, for example, have an effective area that constant as the frequency is varied. If one assumes that the receiving antenna in the free-space path loss model were a parabolic dish, one would conclude that there is no frequency dependence of the loss, since there would be only the inverse 4*pi*d^2 term present. This could be "experimentally verified" by having a link with a dipole antenna on one end and a parabolic dish on the other, which (quite correctly) would show no frequency dependence in its path loss -- it would be the same at all frequencies.
Interestingly, if parabolic dishes (or other constant-area antennas) were used at both ends of the link, the "path loss" would appear to decrease with increasing frequency -- the opposite of what appears to happen if two dipoles are used.
One can vary the antennas used and get whatever frequency response one desires -- but the intrinsic path loss itself is always the same. (Frequencies for broadcast were selected for entirely different reasons.)
The problem is, the effective area of an isotropic antenna is inversely proportional to the square of the operating wavelength.
should be,
The problem is, the effective area of an isotropic antenna is proportional to the square of the operating wavelength.
and
Dipole antennas, like isotropic antennas, have an effective area that is inversely proportional to the square of the operating wavelength.
should be
Dipole antennas, like isotropic antennas, have an effective area that is proportional to the square of the operating wavelength.
Sorry about that.
Also,
Pleasantly, not all antennas have an effective area that is inversely proportional to the square of the operating wavelength.
should be
Pleasantly, not all antennas have an effective area that is proportional to the square of the operating wavelength.
This is why independent review of technical articles is so useful. You can lead a writer to "Preview", but you can't make him think.