[opendtv] Re: News: TV Braces for the Apple Tablet

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
  • Date: Thu, 4 Feb 2010 10:10:00 -0600

Craig Birkmaier wrote:

> In many markets a configuration like Berlin could work. It
> all depends on the geographic isolation of the market. In
> the N.E. corridor the markets are too dense and too close
> together. But these markets have many more viewers, so the
> revenues exist in these markets to build out a more elaborate
> network with better spectral reuse.

I think you continue to blow smoke. The fundamental point is that SFN or not, 
if you need to cover large but individual market areas, you need to protect the 
frequency in adjacent markets. If the market is isolated and you don't need 
continuous coverage beyond the market boundaries to the next market, then 
obviously, big stick or SFN, that problem won't exist. You can reuse ther same 
frequency in the next market over, putting up with interference between the two.

The real savings in frequency usage of SFNs occurs if they go beyond the size 
of a single market. Exactly what Qualcomm has to deal with, given the fact that 
they only had Ch 55 available to them. So for that, the price you pay is a much 
denser mesh of towers. You need that, to put a strong signal in zones that 
would otherwise experience interference. This is probably similar to what 
Jeroen describes in the Netherlands.

Unlike Berlin's Channel 44, Paris and Rome are good examples of low power big 
sticks, SFN, and the need to install translator sites close by, to avoid having 
to install the dense mesh of a single wide area SFN. This might be more like 
your SFN concept. But pay attention:

Paris has a diamond shape SFN, with the Eiffel Tower big stick on the West side 
of the diamond, 25 KW, and then three 1 KW small sticks making up the rest of 
the diamond. To provide continuous coverage beyond Paris proper, scarcely 30 
miles West from the Eiffel Tower you'll find the first set of *translator* 
sites. So as you can see, not much different from the big stick model at all, 
except that you'll get more robust reception in Paris proper.

And none of these examples are ATSC, Craig, so you can't use that excuse to 
pretend like there's some magic possible here that we're missing out on.

Bert
 
 
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