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

  • From: Richard Hollandsworth <holl_ands@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Wed, 3 Oct 2007 12:32:04 -0700 (PDT)

I think the scenaria need to be clarified.....

Towards the "fringes" (and maybe only half-way to Class B limit), DTV viewers 
are 
forced to use attic or roof-mounted antenna systems with moderate gain in order 
to
receive a usable signal.

On the other hand, WSD devices may be located in the bottom floor of a condo/apt
building, or even in the basement and hence would need to be more sensitive.

Basic problem is whether an improvement of 20 dB in sensitivity is enough or 
not.
Given the height gain difference, indoor loss and negative gain antenna 
factors, there are
going to be many WSD devices that do not detect what the OTA DTV is trying to 
watch.

But avoiding active DTV channels is a readily solvable problem via on-line
database lookup (or whatever)....so presumably only the WSD and remote
mike systems need to avoid each other....

But, of course, there are NO White Spaces on Cable (and some SAT systems).

holl_ands

=================================
John Shutt <shuttj@xxxxxxxxx> wrote: 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" 
To: 


> 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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