Microsoft wants you to know that when its white space prototypes malfunctioned during lab tests at the US Federal Communications Commission, the lab did not burn down. Last week, the FCC completed tests of devices from several white space-obsessed outfits, and despite the repeated failure of its own engineering prototypes, …
no, No, NO!!
Stop this train before it gets away from us all.
Unless they are in touch with ALL the users, it really won't work. I'll admit that there are others wanting to grab the spectrum, but LEAVE IT ALONE.
My need comes from wireless Mic's, which in the USA are unlicensed part 15 devices. This is a different application since the operator of the unit controls BOTH ends of the channel. The "white space" grabbers have nodes that have a single "point of view" and while their "signal detectors" might detect some signals, they won't detect all parts (specifically the receiver) of the channel. This is the flaw in the use. Since they can't detect the receiver (even if it is a TV), they cannot say that the space is "unused". The receiving box (whatever it is) may have a nice directional antenna that picks up the signal, and then a more local "white space" thing comes along and blabs its heart out, which can/will be picked up by the receiver it can't detect. The non-"white space" user is then out of luck.
It is like trying to cross the street and only looking ONE WAY. You are sure to get run over!
Half the equation
They can make a device that can spot other transmitters, but it hasn't been proven yet that these wireless devices will not interfere with DTV reception. There is already a large installed base of TV receivers with very cheap tuners. They likely lack the dynamic range and selectivity required to stay locked on the TV station in the presence of stronger local wireless nodes. This "real world" testing has yet to be done. Keep that sparkling cider on ice for now.
Distance and sensing
"...Ian Ferrell estimates that signals will travel a good three miles..."
If the signals travel three miles, that also means they will cause interference for any other devices using the same spectrum within that three-mile area. The problem will be with devices using a lower broadcasting power. Let's use wireless microphones as an example. I don't know much about them, so feel free to correct me, but I would guess they have a very limited range (since they don't need great distance), certainly less than three miles.
Let's say there is an event using wireless microphones (music concert, theater, business conference, etc), and let's say the wireless microphones are using a power level which limits their broadcast range to one mile. Now let's say you and your neighbor each have one of these new white-space-using devices in your houses two miles away (you're setting up a wireless network between your two houses). Because the wireless microphones have a one-mile broadcast range, the white-space-using devices will not be able to detect them, and will say "nothing on this frequency; OK to use". The white-space-using devices will then begin using this frequency, using sufficient power to broadcast for three miles, thus introducing significant interference into the wireless microphone signals.
@ACs x 2
Don't get me wrong, I don't like MS, not one bit, but...
I always get a giggle rising up whenever I see people who use transmitters which (by their own admission) uses an unlicensed segment of the airwaves get up in arms when someone else dares suggest that they too should be allowed to use it.
I'm sorry, you can't have it both ways. Either get the manufacturing companies(or a consortium of same) to "buy" the spectrum your mics use, at which point you can exclude everyone else, OR continue to use the spectrum "free of charge" but stop complaining when Joe Blog decides to do the same.
You guys remind me of someone who camps out in a State Forest and then grumbles because someone else dares pitch a tent within hearing distance. (or VOIP users who complain they have to share the bandwidth with other applications. How dare P2P use bandwidth when they want to make a call!)
These will cause interference. Because a yagi on a TV set will pickup the TV and the WS unit, which due to its small portable aerial(s) won't hear the TV channel.
This is part of the "Cognitive" radio movement which if allowed space to grow will destroy predictable use of bands for long life equipment.
I am a legal Part 74 user of wireless microphones
If you want to make best use of spectrum, the last thing you want is something that goes 3 miles.
Won't Work, Can't Work
As Mage says above, this wont work because it just can't work. Only fuckwits like Microsoft who think they are too big to be governed by the laws of Physics think otherwise.
TV? Who needs it.
I know it's just my 2 pennies worth but hey - TV is shit anyway. As far as I'm concerned they can stuff TV up their you-know-whats. Of course, I'm not a radio wave boffin...
@Distance and sensing
Surely the equipment at both ends of the 2 miles would listen to the quality of the response from the other end and deduce that the signal is being degraded (by the wireless mics), then hop to a different frequency? Again I'm not an expert...