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

  • From: "John Shutt" <shuttj@xxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Wed, 3 Oct 2007 16:48:18 -0400

If you want to use a 200 Hz RBW and put up with a 10 second sweep time over a 10 MHz span, then you can get down to -125 dB noise floor on a spectrum analyzer. However, I doubt that is the mode that Al was using around DC.
When using a spectrum analyzer like our Tek 2712 with a 1MHz RBW and a 10 MHz span at UHF frequencies, you get a more practical sweep rate, and will typically get around an 85-90 dB noise floor. That is what I meant.
----- Original Message ----- From: "John Willkie" <johnwillkie@xxxxxxxxxxxxx>
so, these (non-existant) white space devices are more sensitive than a quite real HP spectrum analyzer? Amazing!
Do they do dishes and windows and stop on a dime, giving nine cents change, too? 

John Willkie

-----Original Message-----

From: John Shutt <shuttj@xxxxxxxxx>
Sent: Oct 3, 2007 9:05 AM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: News: Microsoft, Philips Offer New White Space Test Results 

Al,

I believe your testing in DC, because I've seen it here in Lansing with
ATSC.
However, I will stand by what I said, in that I find it almost impossible to have a null on the pilot that is -114 db, yet have that signal recoverable a 
few feet away.

What you described is a pilot that was maybe -80, dB and recoverable a
couple of hundred yards away.  Any WSD with sensitivity for pilot down
to -114 dB would have still detected a carrier, even if you couldn't see it 
on an HP Spectrum Analyzer.

John
----- Original Message ----- From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx> 
To: <opendtv@xxxxxxxxxxxxx>



One could drive a hundred yards or so from good reception to abysmal
reception.  The transmission antenna heights are pretty low for some DC
area
stations, and the terrain is pretty much hill and dale.





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