[opendtv] Re: News: Microsoft, Philips Offer New White Space Test Results

  • From: "johnwillkie" <johnwillkie@xxxxxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Mon, 1 Oct 2007 12:19:10 -0700


Yes, but cable in particular owns all the interference in their cables, and
can't create much interference outside of their cables.


Kinda sad for the vendors of the boxes, since they will have to start
replacing them.  I hope they enjoyed the temporary price savings by not
having proper shielding for emerging networks in homes.


My Nextel mobile phone interferes with my computers and computers in other
people's homes; we get period 'chugging' sounds in computer speakers.  The
phone has all required certifications, and the computers are class b
certified computer devices.


Then, there's the deliberate interference caused by HdRadio.  


I'm afraid the commission has been ignoring the interference constraints in
the Comm Act for some time, or has redefined interference.


John Willkie



De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En
nombre de Richard Hollandsworth
Enviado el: Monday, October 01, 2007 12:10 PM
Para: opendtv@xxxxxxxxxxxxx
Asunto: [opendtv] Re: News: Microsoft, Philips Offer New White Space Test


WSD only needs a GO/NO-GO detector--which can be narrowband,
looking for NTSC Visual and DTV Pilot Carriers.

Sensitivity is limited by the amount of noise power in the detection
DTV's 6 MHz bandwidth results in a thermal noise of about -106 dBm....so for
WSD detectors
to lower thermal noise by about 10 dB, they would need a detector with about
600 kHz bandwidth.

PS: Bear in mind that the "Listen and Detect" threshhold issue detracts from
the REAL issue:
OET tests found WSD devices cause interference to nearby Digital Cable Ready
(and probably also Cable STB/DVR's and many SAT Receivers for same reason)


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