Aussie Research Company Brings Wi-Fi To TV Antenna

joshgnosis writes "The CSIRO has unveiled new technology that could bring internet to people in rural or remote parts of Australia using their existing TV antennas. Analog TV signal is set to be switched off in 2013 but this technology could see the spectrum used to deliver internet straight into people's homes through their TV antenna. Gartner expert Robin Simpson told ZDNet Australia that this would make it much easier for companies to get new customers. 'What appeals to me about it is that it re-uses existing infrastructure, all of the competing wireless technologies tend to use high frequencies and therefore require new base stations, new spectrum and new receiving antenna infrastructure as well,' he said. 'The fact that they're re-using the analog TV stuff gives them a much easier market entry strategy.'"

Comments

What about uplink?

[AlexiaDeath]

Internet, unlike TV is bidirectional. And a transmitter loud enough for the old TV base station, that covers hundreds of km, to hear at each home just doesn't make sense... It takes a lot of energy to power for example...

Re:What about uplink?

[FrostedWheat]

The return path isn't omni-directional -- the TV antenna at each home will be focusing most the energy straight towards the tower. Also the bandwidth of the data signal will be much less than a TV signal, so it won't require nearly as much power. Such a link could be done with 10mw but it will be quite slow.

Re:What about uplink?

[noidentity]

The uplink is simple. Remember, Australia is on the lower part of the globe, so radio signals work in reverse there. That means it's easier for homes to transmit back to the central station, but hard for the opposite. That's good, because they can put a big transmitter at the central station, rather than having to put them in homes. Too bad that wouldn't work in the northern hemisphere.

Re:What about uplink?

[Anon-Admin]

The problem with your statement (tiny amounts of uploaded data trigger large downloads of data) is that it does not reflect reality.

Small click to upload your video.
Small click to send grandma the 50X8mega pixel photos from Christmas.
Small click to open a VOIP client.
Let not forget sending out most e-mail where the data sent can be rather large.

BTW, the reason you "Recall" seeing the hybrid satellite system is that it died and is no longer available for the reasons stated above. If the upload speed is less that 512kbps it is too slow and the satellite system had an upload of 14kbps. It should also be noted that most hi-speed internet systems are moving the upload speed up higher and higher. Last I checked you could not get a line in my area that was less that 1.5m/3m

So, IMO the internet over TV feq is a nice idea but has a high probability of failure do to limitations on transmit speed and max bandwidth of the frequencies.

Re:What about uplink?

[TheRaven64]

They're aiming this at rural areas, and they will almost certainly be using more transmitters with a lower power than TV, so 10,000 people is probably a lot more than you'd actually get per transmitter. That's a small town, while this is more likely to be used for a village plus surrounding area. And don't forget that that 256Kb/s figure is guaranteed bandwidth. As long as they have some kind of channel negotiation, individual users can grab more bandwidth when they need it as long as the other users aren't all downloading at the same time. Typical Internet usage is full of idle periods and bursts, and as long as they aren't all bursting at once they can probably get 2-10 times that much without any problem.

Re:I wonder..

[MBCook]

Since there wouldn't be a vertical or horizontal blanking interval for the TV to try to latch onto, it would just be static like unused stations used to be. No fun pictures.

I would think that while you could easily receive the signal, transmitting back to the tower would be a problem since TV antennas were designed to be receive only.

Or do they plan to do a satellite-TV type thing where upstream is a modem and downstream is the wireless? Downloading family pictures takes 2 minutes, uploading 6 hours.

My old ATI AIW did this

[schnikies79]

I never saw it in action, but an old PCI ATI all-in-wonder had a driver for networking via tv antenna. I think it might have been one-way, but I can't remember. The manual said it something along the lines of the TV stations being able to send out software or files at specified times. It was sometime in the late 90's I believe.

Of course I never did see it in action.

Re:My old ATI AIW did this

[david.given]

You're not talking about 1980's Teletext, are you? An achingly slow way of distributing 1kB information pages by transmitting data during the vertical blanking interval. It was incredibly popular in the UK for television listings, news and (strangely) holidays.

Also made famous by the BBC Micro, which had a teletext chip in it which could be used as an alternative to its framebuffer graphics modes. As teletext allows you to do eight colour text and primitive block graphics while only using 1kB of video RAM, it was really, really popular, which is why a whole generation of programmers today associate 129 with 'red' and 141 with 'double height'. (I wonder if you can still get the video decoder chips used? They'd be great for homebrew computers.)

Re:I wonder..

[vlm]

I would think that while you could easily receive the signal, transmitting back to the tower would be a problem since TV antennas were designed to be receive only.

Or do they plan to do a satellite-TV type thing where upstream is a modem and downstream is the wireless? Downloading family pictures takes 2 minutes, uploading 6 hours.

Probably upload via phone modem...

Ham radio guys know you can transmit a couple watts thru a typical TV antenna installation.
Issues:
1) The 75 ohm to 300 ohm balun won't survive more than a couple watts. Low power on the HT should be fine. Use 300 ohm twinlead and you can shove a hundred watts thru a typical TV antenna.
2) Terrible gain per pound or per sq foot of wind load. All that aluminum is for wideband gain as opposed to narrow band gain. You'll be very displeased with the performance compared to a "real ham radio antenna"
3) No inline booster amps for obvious reasons.

Biggest problem is legal, at least in the US, no unlicensed intentional radiators at any power level allowed in the TV bands... Going to take FCC rulings, maybe congressional bills. Probably just as bad in Australia.

Re:I wonder..

[PolygamousRanchKid]

I would think that while you could easily receive the signal, transmitting back to the tower would be a problem since TV antennas were designed to be receive only.

My father designed TV transmission antennas for RCA (for instance, the one that was on the World Trade Center). He told me that, during construction, they tested the transmission antennas, by using them as receivers. My I visited the construction plant with him, there were a bunch of the sections of the World Trace Center array lying around. We went up on the test platform and he showed me that they had a line of sight to the spot in the distance where the test transmitter was located.

Cool stuff.

Re:I wonder..

[morgauxo]

'take FCC Rulings'

Umm... Go have a nice hot beverage. I'm sure you could use it after being frozen the last few years. There have been how many stories about just that taking place here in the US? I can only guess by this article that something similar is happening in Australia. Of course, here in the US wireless mic people have been broadcasting illegally for decades.

Re:upload vs. download?

[donscarletti]

swirls their toilet flushes backwards.

Contrary to The Simpsons, Australian toilets don't swirl, the standard type I believe is called a "non-siphoning washdown", which basically means that the velocity head at the start of the s-trap during a flush is greater than the elevation between the bowl level to the peak of the s-trap. Usually this means the toilet has a slightly higher cistern than American varieties and the s-bend is lower and around double the diameter. The upshot is that this kind of toilet uses less water, since it relies on kinetic energy, not volume which also suits the Australian climate. Also that fecal matter is removed almost as soon as the button is hit is comforting for some. The drawback is that older designs of washdown are slightly unreliable compared to American style siphon toilets, since if the flush's velocity is lost due to a badly shaped bowl or an obstruction, there will be no way of building the hydraulic head needed to complete the siphon in the S-bend and empty the bowl.

Toilets are so deeply entwined in social norms and so rarely discussed that they become one of the most unexpected parts of traveling the world. Australia and America's common traits such as common language are reflected by the seated (not squatting) position and the fact that fecal matter falls directly into water. The contrary mindsets are evinced by the Australian direct approach of a sudden wave of not quite enough water to instantly clean away most but not all, compared to the American steady but wasteful surge which bobbles the shit halfway to the rim, before finally sucking it away completely when it can take no more.

Re:I wonder..

[mcgrew]

An antenna is an antenna. The only thing you have to do is tune it to the correct frequency, and that's trivial; a matter of length.

There's no difference between an antenna for recieving and one for transmitting -- it's just a piece of the right length of wire. Notice that your cell phone only has one antenna, not separate and transmit antennas?

Re:I wonder..

[postbigbang]

Everything is an antenna, it's a matter of matching the wavelength efficiently to the tranceiver source and the directional relationship between transmitter and receiver. A TV antenna is like any other antenna in that the best reception and transmission have to do with the little tynes or rods or radiators on them matching the exact frequency desired. The old set top monopole and dipole antennas can be tuned by moving the collapsing rods to match the desired frequency. Barring that, it's not as efficient. Sometimes a quarter wave, half wave, eigth-wave can do the job, but tuning it helps.

Once you use an existing TV antenna to transmit, you're captive to the wavelengths (rod lengths) it has; there will be some efficiency but a lot will be lost. Then, the problem becomes having sensitive receivers upstream to be able to correctly discriminate the desired signal-- and make sense out of it at distance.

It's at this point where I think things go awry, in that the electronics used to send a signal are designed to do so radially with perhaps megawatts to get to their desired TV antenna to produce an adequate picture. A couple of watts might get you quite a ways (125mi+) with highly tuned directional antennas (like the famous WiFi Pringle can projects adjunct to DefCon meetups) but these aren't highly tuned, directional antennas. A couple of watts gets you to the end of the block on a good day.

Re:I wonder..

[Stewie241]

The Wi-Fi in the title is misleading. They are reusing the frequencies that broadcast television used to use.

Re:I wonder..

[reason]

The "Company" in the title is misleading, too. CSIRO is a government agency, akin to the USGS or NASA.