What is Digg?32 Comments
- mykos, on 10/11/2007, -1/+25Television stations are given GIGANTIC frequency ranges for each channel, but with digital broadcasts becoming the requirement (and if they all start using MPEG-2 or MPEG-4 compression) they will take up far less space than they once did. Excellent idea.
- smackhero, on 10/11/2007, -2/+18i'll support anything that results in better connectivity and faster speeds for my bittorrent downloads, but i think TV communications will eventually just be replaced media streamed over the internet.
on a side note, if you pass the "White Space Coalition" to trim() or ltrim() do you just get Coalition? - jaym, on 10/11/2007, -0/+14Quite the opposite. Lower frequencies are more penetrative - think if your neighbor is playing some rock music, you can only hear the bass part not the high frequency part. Also if you drive under a freeway, your radio can only receive AM signals (10k Hz range lower frequency) not FM (MHz, higher) signals.
However, higher frequencies can transmit more data faster so it is a trade-off. - Bossman1086, on 10/11/2007, -0/+7Wow...this is exactly what needs to happen for city-wide WiFi to be prominent in the majority of places. It'll be cool if this works out.
- lieutenantmudd, on 10/11/2007, -3/+8The standard has already been set. Broadcasters can't all the suddenly decide to start using a better codec. The rollout is already going to be a big enough headache. The ATSC standard calls for MPEG-2 encoding and each channel is enough for 1080 video. You aren't going to see MPEG-4 compression.
- babar77, on 10/11/2007, -0/+5Actually, there are a lot of things that affect the range of a wireless device. Path loss through free space is one of them. Absorbtion and reflection of materials also affect it. 2.4Ghz has one of the greatest losses through air (esspecially humid air) because the resonant frequency of hydrogen is at 2.4GHz. This is why microwaves are 2.4GHz so that they wiggle the water molecules thereby generating heat.
Matching an antenna at 2.4 and 5.8GHz can also be a problem due to the fact it's hard and expensive to manufacture boards without (or lower) parasitics such as stray capacitance at those frequencies. This is due to the structures needing to be so small. Sure it's easier to do in an IC, but it has to leave the IC eventually.
2.4GHz in also absorbed by the human body because we are essentially water. 900MHz is reflected more because it's wavelength is greater than 2.4 GHz, which can help or hurt you depending on the situation. If you are worried about your brain heating up (even though it's only very slightly, hardly measureable) then I would suggest you don't use a 2.4 or a 5.8 GHz phone. - loneraven, on 10/11/2007, -0/+5Uh... no you're wrong.
A 900 mhz phone will penetrate walls better than a 2.4ghz phone.
A 2.4 ghz phone will penetrate walls better than a 5.8ghz phone.
And so on. With phones for example, you're basically balancing effective distance with penetrating power. 2.4ghz imo, is the sweet spot.
Edit:
doh! too late - inactive, on 10/11/2007, -0/+3Matching at 2.4 GHz is child's play nowadays :). Try matching at 60-90 GHz... and make it tunable... now things get interesting.
- Dougman82, on 10/11/2007, -5/+8The most interesting part to me isn't the potential download rate, but the fact that the lower frequencies can pass through walls and other obstructions more easily than current 2.4GHz wireless signals.
- discourse, on 10/11/2007, -0/+2this sounds great. hopefully more remote places would be reachable with this technology.
- slapthemonkey, on 10/11/2007, -0/+1Sounds good
- TRENT310, on 10/11/2007, -0/+1"Also if you drive under a freeway, your radio can only receive AM signals (10k Hz range lower frequency) not FM (MHz, higher) signals."
Not really, AM signals are blocked by large concrete structures usually. Some AM stations in the city have set up FM translators in the Downtown areas to serve people within office towers.
However I never listen to local radio stations (mainly because of the ads) so I just pick up rural AM stations, and a 10,000W AM signal will go WAY farther than a FM Broadcast signal of equivalent power. The AM signal will go even father at night. This is why we have 100,000W FMB stations and 50,000W AM stations, the extra power is to make up for the bad signal propagation on FMB. (CITI-FM Winnipeg, MB, CA once operated at 210KW because of this.)
Higher frequencies don't bounce as well. A weak FMB signal sounds like static, and tends to waver if you're moving, but a weak AM signal just isn't as loud. (But other noise sources like power equipment will overpower that lowered signal strength.)
----
2.4GHz isn't the best frequency for those low power consumer electronics (phones/wifi/etc.) which have moved from 49MHz, 900MHz. It's also the same freq as microwave ovens, and microwave oven cages aren't completely sealed and will still leak some RF energy, messing up any other transmissions in the same band. And it doesn't go through air or water too well either. Last time I checked >30GHz frequencies were unregulated, maybe they are now. Then maybe everything can contain microscopic antennas because of the short wavelength. - williamdyer, on 10/11/2007, -0/+1Smart radio FTW. The idea of reserved spectrum is a dinosaur.
- carlosglz, on 10/11/2007, -0/+1I wonder what the upload speed on this could be...
- babar77, on 10/11/2007, -4/+5Well it isn't just the actual TV broadcasts that are trying to be protected here. There are also secondary devices that operate there such as wireless microphones. Ever wonder how you can hear the base-runner run over a base in baseball, or hear hits and crunches in football (American Gridiron for you non-US readers)? Ever wonder how large productions such as the Grammies and political conventions are coordinated? Ever wonder how your favorite concert can pull off the choreography or high production qualities of today? How you can now hear every actor / actress at a Broadway show? Or hear a pastor at a church (I know bad crowd for that question)? All this is done with professional wireless microphones, sometimes hundreds of them.
Ever hear the buzzing sound that your GSM cell phone creates when you get it too close to your TV or speakers? Imagine if you just shelled out $70-$1000 bucks for concert tickets and it was reduced to the band just standing there and playing, or you constantly heard that annoying sound over the PA because people won't turn their cell phones or other personal/portable device off. Hell people are using their cellphones as candles at most concerts these days. Imagine if that sound kept coming over the air during the Superbowl whenever the ref was trying to give the call on the field. Imagine if a public speaker the likes of Martin Luther King Jr. were around again, could you imagine what it would be like if every time the news crew tried to interview them, you heard a buzz? Or if some reporter is trying to get some information out of Ken Lay (I know dead) for what he did at Enron and you couldn't hear his response?
Parts of the UHF spectrum is being used for public safety as well.
I'm not saying that wireless 80Gbs internet access isn't an awesome idea. I'm just saying that if it isn't done right, there are A LOT of things that we have come to take for granted that would be affected, even if the TV stations all moved to broadcasting over the internet. And what good is an internet connection if the content being offered now sucks? The internet is only as good as the content on it. That's why it exists. - macnerd, on 10/11/2007, -2/+2DTV broadcast occupies the same 6mhz space that analog does. What the FCC is doing is taking a lot of the UHF space back from the broadcasters. As others have said, MPEG 2 is the standard for ATSC, I don't think you ever see MPEG 4 decoded over the air in the home. Broadcasters can include MPEG 4 in the DTV stream but a viewer at home wouldn't be able to view it since ATSC receivers are MPEG 2 based.
- coldfusioneer, on 11/11/2008, -0/+0http://www.marketwire.com/press-release/Voyant-Int ...
These guys are already manufacturing commercial-grade white space radio device not just for broadband, but also innovative uses such as long-range radio control of devices and data transmissions.
Think smart traffic signals that's solar-powered with LED signal lights, with software-defined signal processing, video streaming of traffic conditions, image/on-ground traffic sensors, automated with central control and central data processing. ALL WIRELESS and GREEN! - inactive, on 10/11/2007, -3/+3I work for Philips as well.
- davidrools, on 10/11/2007, -1/+1I like how the Philips prototype module is running in MATLAB
- sicapitan, on 10/11/2007, -1/+1I wonder if the Superclub Superfriends are going to use it
- steveooo, on 10/11/2007, -0/+0maybe thats whats killing the bees!!
- Bersy, on 10/11/2007, -1/+1Uberfast download speeds are all well and good, but can someone explain to me how upload is supposed to work over this "white space" when it's more or less just a television transmission? Can we expect symmetrical up/down speeds?
- Topher06, on 10/11/2007, -0/+0Ultimately, its digital data, so you could easily see "enhanced quality" channels in the future that might use MPEG 4 or even other codecs. I definitely expect 1080p channels in the not to distant futures (actually broadcasting 1080p, not just upconverting them). The requirement is you need a new box to support the enhanced channels, but its not inconceivable that new standards can be introduced at a much more rapid pace with digital technology then with the old analog standards. Lets face it, the time for televisions to have integrated tuners is over, its almost pointless to buy a TV with integrated tuner and more companies are simply not offering tuners in TV's anymore (or just have an analog tuner). The cable companies are going to ensure they keep their fingers in the pie by renting or selling their own proprietary cable boxes. If a new standard comes along that makes it cheaper for cable companies to deliver content, but allow them to charge MORE for enhanced features, they are going to find a way to do it regardless of how customers feel about them making their TV obsolete, or at least the built in tuner.
I currently have a range of analog channels, and then standard def digital equivalents, and then HD equivalents spread across 900 channels. On-Demand channels have popped up along with pay-per-view and music channels. So why shouldn't I expect a block of enhanced full 1080p HD channels in the near future? The problem is that the FCC has to stop thinking like everything is analog which takes a 'coons age to standardize and implement. - ShaunOlsen, on 10/11/2007, -1/+11Hz - 10GHz should be used for wireless ethernet and everything that currently uses those ranges should be converted to the wireless ethernet systems.
- hello2usir, on 10/11/2007, -4/+3That's what she said
- lieutenantmudd, on 10/11/2007, -4/+1I had a GSM phone in Europe, and I would hear static on my computer speakers a second before my phone rang or before I got a text message.
- JrGhoull, on 10/11/2007, -5/+1"The goal of the White Space Coalition is simple: take advantage of unused television spectrum to provide wireless broadband."
gee golly i wonder why i didnt think of that... /sarcasm - KineticShampoo, on 10/11/2007, -7/+1Anyone see this movie?
http://www.imdb.com/title/tt0454919/
I'm scared. You should be too. Hehehe. - inactive, on 10/11/2007, -9/+1WIFI through my tv sounds good!
- pyrotechnick, on 10/11/2007, -16/+2No. Higher frequencies are more penetrative. Do some research before you make silly comments like that.
Digg is coming to a city (and computer) near you! Check out all the details on our 
© Digg Inc. 2009
— Content created and posted by Digg users is