[opendtv] Re: A more intelligent way to deal with the White spaces?

  • From: Albert Manfredi <albert.e.manfredi@xxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Sat, 1 Nov 2008 18:13:04 -0400

Craig Birkmaier:

> The white spaces debate continues to amuse me.

Me too. Because the advocates never address the issues. Or they are totally 
confused about the issues. Lots of arm-waving going on, no addressing of the 

There are good ways to use white spaces. But that doesn't include consumer 
devices blasting away from any location.

> The FCC testing demonstrated that this spectrum CAN be shared.

You obviously haven't read the report, if you say this. The most positive 
result was that a combination of geo-location and auto-sensing was consistent 
in determining which local channels were *occupied*. But that's all the report 

Once the frequency channel was correctly determined to be open, interference 
will still result, even with the lower ERP levels the report assumes. And 
making this concession to reduce auto-sensing-only ERP from 100 mW to 50 mW is, 
sorry to say, a joke.

And no way were auto-sensing-only devices feasible, in that report.

Look at the numbers, Craig. It's not hard to understand. A WSD at 10 meters 
will create an undesired noise level in the -31 dBm region, co-channel, or in 
the -52 to -62 dBm region in the N+/-1 and N+/-2. This will obliterate a large 
number of legitimate TV signals. Not to mention Charles Rhodes' point about IM3 
created by two WSDs. Address these points, please.

> Why do broadcasters have any more claim to this spectrum
> for a "new" service than other potential users of this spectrum?

Because it's their spectrum. Perhaps broadcasters can make the same argument 
about using the DBS spectrum? Or the WiFi spectrum? Or how about allowing WSDs 
in the GPS spectrum? Why not allow broadcasters to blast away from their high 
towers in the 2.4 GHz band, for "new services"? Broadcasters have given up 200 
MHz of spectrum for cell service, in the 1980s and now, so it's not like 
nothing has changed.

A good compromise would be to allow only the low VHF for consumer devices, and 
allow sharing of white spaces otherwise only for fixed broadband service, where 
channel assignments can be done intelligently.


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