[opendtv] Re: Seeing Ghosts on a Single Frequency Network

From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
Date: Sun, 13 Feb 2011 17:49:55 -0600
Craig Birkmaier wrote:

> It has been fun to watch the MFN SFN debate. As an "unbiased" observer,

That makes me laugh. Unbiased observer? Craig, you have been using the vague 
allusions to SFNs, vague ideas about placing towers around the beltway, as why 
COFDM is the only viable choice from day 1. You're as biased as they come!

>> Certainly, you cannot deny that a big stick to cover a single market is
>> more spectrally efficent than a SFN *to cover a single market*. Right?
>> That was the original trade.
>
> This is ONLY true if we are talking about a market that exists in
> isolation - that is, it is sufficiently distant from any other market
> that one does not need to consider the loss of white space channels
> in adjacent markets.

No. It is true whenever you have adjacent markets that require overlapping 
coverage, such as cities up and down the East Coast. With single market SFNs, 
you continue to require white spaces in these cases. Once again, pay attention 
to real-world SFNs, the ones actually in existence, to see that this is how 
they are built.

The range of big stick coverage is PURELY a function of how large the markets 
that they cover are. You can always reduce the power of a big stick, Craig, if 
the market size doen't warrant the coverage. Our CW20 channel here, in the 
early days of the transition, had a ridiculously small coverage area, a handful 
of miles, even with a big stick. You continue to misrepresent what big sticks 
are. Similarly, in Paris, the big stick only transmits 25 KW in UHF. Which 
means that 30 miles away, you have your first set of translators. Big sticks do 
not necessarily mean you can't reuse the frequencies for hundreds of miles. It 
all depends on ERP. It all depends on how the frequencies are reused. I've 
given examples before, which you quickly forget, so I repeat them below.

If big stick frequencies can't be reused for 200 miles up and down the East 
Coast, by other high power big sticks, it is because THAT'S HOW BIG THE MARKETS 
ARE that they need to cover. Between Baltimore and NYC, Craig, the only major 
market is Philadelphia. NYC and Wash/Balt share many of the same frequencies. 
Why wouldn't they? What would SFNs do differently?

What's more, LPTV transmitters in market A *can* reuse the frequencies of a big 
stick in the adjacent market B, as long as the LPTV sticks are located far 
enough from the boundary. No different from what you'd achieve with the SFN.

The FCC permits Channels 7 and 13 (VHF), 30, 33, 35 (UHF) to be used in 
Wash/Balt, and the same Ch 7, 13, 30, 33, and 35 (low power) to be reused in 
Phila., the adjacent market to Baltimore. Ch 42 in Annapolis, Ch 42 in Phila. 
So honestly, in the face of all this real-world information, both here and 
abroad, I just don't understand why you insist on keeping fairy tales alive.

> In the case of using SFNs in dense urban areas, there is NO way that
> big sticks or MFNs can provide the spectral efficiency of properly
> designed SFNs.

That's false. If the big stick needs to be supplemented, e.g. for more even 
coverage for mobile devices, it can be supplemented either by low power DOCRS, 
aimed downstream of the big stick, or by low power translators whose 
frequencies can be reused in the adjacent market, and match or exceed the 
spectral efficiency of a SFN. And certainly can be done with fewer towers and 
fewer compromised locations.

> Broadcasters WANT localism.

Fine. One extra nail in the coffin of SFNs. Because I'll certainly agree that 
SFNs, if used in large, multi-market regions, could save on spectrum. That's 
obvious. At the cost of a complicated and kludgey infrastructure. But take that 
away, and there's no excuse to continue this charade.

> Near as I can remember, Bert is the only person calling SFNs Cellular TV.

Either you don't remember, or you continue to misunderstand. I have described 
cellular TV, but when I did, I explained true cellular TV. Not some half-baked 
inaccurate term used to befuddle politicians and other innocents.

Bert
 
 
----------------------------------------------------------------------
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.
Follow-Ups:
- [opendtv] Re: Seeing Ghosts on a Single Frequency Network
  - From: Craig Birkmaier
[opendtv] Re: Seeing Ghosts on a Single Frequency Network

Other related posts:
