Google are leading the charge to free up "white space" - now that analog TV is being shut off, there's a load of spectrum that will be unused. The FCC in the USA is either A) doing nothing or B) selling it to a few companies for exclusive use. Instead, it should be opened up and used for internet access. Imagine wireless networking with the range of television reception. It would be amazing!!

Google have set up a website called Free the Airwaves, where you can learn more about this. Sure, it's only in the USA, but no doubt this will be an issue impacting us world-wide when other countries decide to turn off their analog TV networks.

I spent the past 45 minutes watching the videos Google has made, interviewing a range of people as to how freeing the airwaves will impact them and their communities.



I personally think the vision of ubiquitous internet is a glorious one and one I hope to see very soon. The Internet is a great leveller and hopefully getting it into the hands of everyone means society at large is changed for the better. </idealism mode off>

Free the Airwaves

NOOOOOOOOO!!!!!!!!

*digs a holoe under Uluru and moves in*

But it's using analog TV spectrum, Brains.

And this is awesome. Except I don't see how it's any different to what we've got right now with 3G, etc. More coverage, I suppose. Possibly faster but I am not expecting any miracles.

I kind of thought she was a dude too, before hitting play.

UMTS/HSPA is still controlled by a handful of companies and is licenced spectrum. What Google and others are proposing is an open spectrum, like Wi-Fi, but much more penetrated (imagine wi-fi with TV signal coverage).

Something like this is ideal for Australia, as it reaches rural areas (a big reason why things cost so much for us in the metro area, as we support the un-profitable rural areas)

This has to happen.

It would bring total connectivity to the world.

Hells yes.

Sorry for getting too technical, but how does data flow in the other direction? I can understand fast downloads, but how does the upload work?

+1 from this little black duck! Once again MacTalk gets the info to me before Slashdot!

And leave that idealism mode on, we need more idealists. Ideals are what we have to aspire for to get our realistic best.

I didn't think the uhf frequency would be fast enough to carry wireless data. Isn't TV in the order of megahertz?

It's about using the freed frequencies, not the actual TV equipment. The new equipment that would be built for a freed up TV band would be duplex. It's just long range wifi.

The 400Mhz band is wide enough that the data could be spread all across it like vegemite on toast. I'm sure Google engineers know what they're talking about, anyway.

That isn't really possible, there are existing UHF users already. Any plan that was implemented would need to be able to demonstrate zero interference to existing primary service users on existing frequencies.

Just think about what could happen if the local fire brigade or ambulance or police couldn't receive a radio call because the UHF wifi was causing interference. In addition to emergency services many commercial companies use UHF (our bus company pays for frequency access on the shared system used by the emergency services). There are taxi companies, trucking companies, courier companies and many many more.

Don't get me wrong, I'm not saying it's not possible (but I'm not saying it is).

I'm just saying that it isn't as simple as people might assume and lots of preliminary research and testing would need to be done first. And it might well involve compensating existing users with $ to cover the costs to relocate frequencies (assuming other frequencies are available and/or viable).

Bottom line... it isn't just TV that uses UHF.

Listen to Jaali; the reason that TV has a range of 100Km is that they have towers a hundred metres high, and pump out thousands of KiloWatts.
How is, say, a laptop or home wireless router pumping out 0.1W ever supposed to participate

No, if we're going to talk ubiquitous urban networking, we need to talk mesh networking, and once we hit the outskirts and rural areas, it must be low-Earth satellites.

I for one reckon that if anybody could crack a technology that could use TV interference free, it's google. I'm not talking out an untechnical a*** here, either. Before I worked in radio broadcasting, I worked for (then) Telecom in the wireless trunk area (the original broadband ), even back then we had systems which multiplexed some signals across several "white space" bands with no interference. Granted they were analogue.

If you use many allocated channels as many available ports (not ports in the IP sense, but in a signal diversity sense) and use spread spectrum encoding, the likelihood of interference into nearby bands is negligible. Like I say, if anybody could make this work (and many could) Google certainly could.

There are two reasons TV signals have longer range than wifi. The power one is obvious, this is fixable by using cellular technology, spreading a mesh of receivers across a wide area surrounding a large transmitter. The other reason TV gets out further than, say WiFi, is because it's a lower frequency. Higher frequencies tend to behave more like light and fail to pass through walls. TV is more able to pass through (and refract a little around) solid objects.

Most of the mathematics for these sort of wireless systems was developed by radar scientists and code breakers in WWII. Not specifically for wirelles networking, of course, but wireless data makes clever use of the initial theories.

No, 400Mhz isn't likely to give you gigabit ethernet, but it could provide a deep backbone that could be augmented for speed by wired technologies where needed.

I've seen the results of spread spectrum use and in every case I've seen it has not been interference free (although in some cases it was claimed to be).

Spread spectrum technology results in a raising of the noise floor (and yes for many users with strong signals that won't matter). It will matter for users where signal to noise ratio is of critical importance though.

So users like police UHF or our own commercial 2 way units would probably be ok (except for a slight reduction in range at the edges of the coverage) but low signal users such as radio astronomers and VHF/UHF SSB/CW long distance using radio users would almost certainly not be.

The problems of this technology are analogous to those that are caused by BPL and the solutions are even more expensive. For this to work signals generated would need such strict (and hence expensive) band pass filtering that it would almost certainly make it commercially unviable... *unless* the interference regulations were changed (and that's not going to happen any time soon).

Honestly... we are talking about home wifi type units that would sell for a few hundred dollars at most that would need filters to restrict interference outside the TV bands costing hundreds of dollars on top of that (at a minimum). 30 to 40db down isn't going to cut it... we are talking 60 to 70 db at mininum in order to retain existing users low signal performance.

I really can't see that being viable for home units.

But hey... if they can do it without impacting existing users then more power to them

That would be awesome - everything, including radio stations and TV, will run off the web.