[opendtv] Re: Genachowski pitches his upcoming national broadband plan

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Sat, 27 Feb 2010 08:25:35 -0500

At 4:41 PM -0600 2/26/10, Manfredi, Albert E wrote:

So far, nothing you have said is different between SFNs and big sticks, EXCEPT for the fact that "use of directional antennas" as a solution will be far more reliable with the big stick. Reason being, the strongest source in a dense SFN will vary with all sorts of weather-related phenomena, making the correct orientation a crap shoot. Hey, wasn't that supposed to be one of the advantages of SFNs? That antenna aim becomes much less important? Well, this can work against you.

Once again you pounce without a clue...

I was not talking about receive antennas I was talking about transmission antennas. It is quite easy to set up masks on transmission antenna to control coverage. Thus I might use an antenna on the north side of a market that provides coverage to the south, thereby making it possible to re-use that frequency in another market to the north.

And yes, the whole point is to saturate the desired market with signal that is well above the threshold for reception; if we could use DVB-T a receiver would typically get signal from more than one transmitter site. If weather is a reception issue you are doing something wrong.


And again, if the SFN is not dense, then the coverage contour will look very similar to that of the big stick, as it does in the Berlin case. And the orientation of a receive antenna will also be less effective than with a big stick.

The coverage contour is important, but not as important as the signal levels within that contour. With multiple transmitters it is possible to provide more uniform signal levels and to deal with terrain and building blockage. Big sticks do not provide uniform coverage - you may need to attenuate the signal if you are close to the tower, and you will need to deal with coverage areas that have nasty multi-path (multiple signal levels).

Cellular netwoks are NOT SFNs, Cellular networks are just low power big stick equivalent systems, where you CANNOT get away with anything better than 50 percent usage of the spectrum in any given location. The only point that can be made here is that cell-like dense mesh can create a sharper contour pattern. That's all.

The only point here is how dense the mesh can be - specifically what is the distance between cells that re-use the same frequency. The closer the cells, the higher the spectral re-use and thus spectral efficiency.


I totally disagree. Along the two coasts especially, it would be simply inexcusable to deliberately deny coverage to the populated areas between major markets.

No one is being denied. There are MANY smaller markets that fill in the gaps.

There are six large markets in the N.E.

New York -1
Philadelphia - 4
Boston - 7
Washington D.C. - 9
Baltimore - 27
Hartford and New Haven, CT - 30

And a bunch of smaller markets:

Harrisburg-Lancaster-Lebanon-York, PA - 39
Providence, RI-New Bedford, MA - 53
Wilkes Barre-Scranton, PA - 54
Albany-Schenectady-Troy, NY - 57
Syracuse, NY - 83
Salisbury, MD - 144
Binghamton, NY - 157
Utica, NY - 170
Elmira, NY - 176

And a bunch of stations that are in sub markets that lie near major markets:

For example, there are stations in Annapolis, Fredrick, and Salisbury that are part of the Baltimore DMA. There are stations in Delaware including Dover, Rehoboth, Seaford and Wilmington.

I could go on and on...

The same situation exists on the west coast. If there is a significant population there is typically a TV station.

HOWEVER, let me point out the obvious. Big sticks can easily be used this way too. You can easily assign the same broadcast frequencies to the ABC affilate in Baltimore and the ABC affiliate in Philadelphia. perhaps the ERP can be lowered somewhat compared to now. Then you can tell Cliff, "Hey Cliff, try pointing a very directional antenna either to Phila or to Balt, and if you can't get a decent signal, here is the number for DirecTV." This would work, Craig. Users in Phila proper or in Balt proper should have no problem watever, even with big sticks. But the FCC should not be marketers for the subscription services. That's not in their charter either.

Sorry Bert, but that would NOT work. There would be large areas with overlapping coverage, but the content of the signals would be different most of the time.

This COULD work if both stations carried the exact same bits, but this becomes a regional network then...

Well, EXACTLY, Craig! The law of unintended consequences. That's what I'm trying to get across. All the vague mention of "SFN" as a means to save on spectrum never gets fleshed out. What are we talking about, anyway, that actually saves on spectrum? How is spectrum saved with SFNs? Saving spectrum with SFNs has to mean using the same frequencies in adjacent markets. So, unless you deny coverage to many intervening communites, you muct create larger regional signals. What exactly does the FCC want to do here?

Maintain the market based system.

The reality is that a properly designed transmission network would provide more channels per market using less spectrum than today. And that's the whole point. Too much spectrum lies fodder when you use big sticks in densely populated areas.


 One can also argue that reassignment of the broadcast spectrum for
 broadband is a viable alternative, which would allow consumers more
 direct control of the content they want to access via the public
 spectrum resource.

More direct control? Have you been following all the machinations the content owners are coming up with, for delivery over the Internet? I would argue that the opposite is true. I would argue that over the Internet, especially when unicast (which is where they are going anyway), the content owners or content distrubutors will have far GREATER control of how the content is received.

Yes, more direct control Bert. If people can pull the content they want on demand, they WILL watch what they want, not what is ON at the moment. Broadcasting only provides a real benefit if MANY people want to watch the same thing at the same time. Those days are mostly behind us except for a few large events...


I agree that the broadcasters need to get in on the act loudly. But I also think that the FCC needs to say things as they are, not to blurt out words whose only purpose is obfuscation, to further some newly hatched agenda they have to deal with today.

The FCC is saying how things are. The Broadcast service is highly inefficient with respect to spectrum use and the service is not being used by the vast majority of Americans. Something has to give and the FCC is starting that ball rolling.

I suspect that many stations will simply cash out...

Those that remain "may" try to build something new and useful. Time will tell...

Regards
Craig


----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.

Other related posts: