HD Wireless Streaming at home

[airpolgas]

Why is this technology so hard to accomplish?

I am under the impression that the idea is to send the signal thru the air, and be received by the TV/Decoder/etc. before going to the display. When I read about it though, most of the limiting factors are the bandwidth constraints, because the HD signal is so big.

If that is the case, why do we get our HD programming by just having an ATSC tuner and a nice strong signal from the station?

For the sake of argument, lets say an hour HD show is about 1GB. How do the stations distribute that to an entire city? Do they actually send out 1GB worth of data per ATSC tuner that can connect to their signal?

[Nick]

It's called "broadcasting" -- never heard that term before? It's a fairly
recent technology that's only been around for about a hundred years.
I first learned about "broadcasting" when I was about 10 years old.

[airpolgas]

Sarcasm aside, I know about that. But what I am trying to find out is the difference between the signals coming from the broadcasters, and say, from my PC, which I want to stream to my HDTV. If they're just a bunch of ones and zeroes, why is there no product that can just send a fairly low signal (the target area is just basically a house), and emulate what the broadcasters do city wide.

[Nick]

You asked "How do the stations distribute that to an entire city?" I just answered the question you asked.

I do precisely that in analog mode. I distribute my various program sources through a 5>1 a/v switch wired
into a single wireless transmitter, then through the air to any number of receivers (tvs and monitors) around
the house. There are no theoretical limits to the number of receivers to which I can transmit, within range of
the signal. The same principal would hold true for digital signals.

I've been asked that question before -- by people who should know better.

[AllieVi]

Why is this technology so hard to accomplish?

I am under the impression that the idea is to send the signal thru the air, and be received by the TV/Decoder/etc. before going to the display. When I read about it though, most of the limiting factors are the bandwidth constraints, because the HD signal is so big.

If that is the case, why do we get our HD programming by just having an ATSC tuner and a nice strong signal from the station? ...Standard-definition transmitter/receiver pairs have been available at reasonable cost for a long time. I use some for security cameras to allow moving them from place to place. The units don't operate on a normal broadcast channel, though, so a pair of devices is needed.

As you suggest, there's nothing really different about sending/receiving HD. Manufacturers simply haven't made low-cost transmitting/receiving equipment available. The bandwidth is significantly higher, so existing SD gear won't work.

Be advised that the FCC could get very nasty if you tried to broadcast on a normal channel.

[cdru]

The difference is interference. Consumer equipment must operate within a fixed frequency band. Unfortunately every manufacturer and his brother also use this same band. The amount of overhead to account for interference, error detection andcorrection, etc eats up a lot of that bandwidth.

Television stations however have less of that to deal with. The FCC allocates a frequency block to use and they get exclusive use of that. They don't have to worry about their neighbor firing up his transmitter and using the same frequency.

[ntexasdude]

Many many moons ago I was broadcast engineer for an analog small market FM radio station. A job that ultimately resulted from my Air Force tenure in radio and telephone. (Yep, it's true DonLandis). Then somewhere I got smart and switched to mechanical design engineering. I have always missed the electrical engineering part although I make more $$$ in mechanical. At any rate, I could bore you to death with intimate details of RF propagation, antennae design and what not.

Nick, in his simple explanation, nailed it. And cdru with his explanation of interference is also on track. You can buy a 5.8 ghz cordless telephone with a one mile range but why would you want to? I only want my cordless signal to reach my house and my backyard. And, I don't want my neighbors signal interferring in my domicile.