[opendtv] Re: Did I get this one right?
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 19 Oct 2007 18:36:02 -0400
Craig Birkmaier wrote:
> Based on the responses to this thread. one fact seems
> apparent:
>
> The white spaces have significant potential for the delivery
> of new services that might be used by a significantly larger
> portion of the population that DTV.
Basd on the responses, and based on tests, I'd say also that use of
white spaces has to be done carefully. The problems are (a) that
automatic RF detection mechanisms are difficult to implement correctly,
for many reasons already described, (b) that interference on other
channels than the one intended for use is also an issue, and (c) that
these devices also interfere with cable receivers, for which no white
spaces exist. A fortuitous state of affairs for OTA broadcasters, I'd
say.
If power is kept way down, and if the frequencies are administered
intelligently, then such a scheme could work. So that's why use by
broadcasters, or some other administrator, COULD be made to work. Much
like LPTV can be made to work.
> One must look at this situation from two related perspectives:
>
> 1. Protection of existing users/services is very important; as
> with any proposal to share spectrum, the key issue will be how
> much interference can be tolerated.
And what you seem to ignore is the range between these potential new
transmitters and existing receivers that use the TV spectrum, compared
with the range between receivers and TV transmitters. The allowed 1 watt
level is very high, if it's right across a drywall from a TV.
> 2. licensing is a viable method to control the alternative uses
> of this spectrum, but it also opens up a can of worms related to
> the value of the spectrum that is being shared.
That's another matter entirely. I'm just addressing RF issues.
> Current incumbents, both the broadcasters using the TV spectrum
> and the companies that provide broadband services today
> (primarily cable and telco) would like any alternative use of
> the spectrum to be regulated and presumably encumbered with user
> fees so as to make these alternative uses less competitive with
> existing products/services.
Again, this has nothing to do with the RF problems. It's fine to go off
into other reasons why TV folk might not like this, but that doesn't
undo the actual real issues with RF interference.
> So, as usual, the real debate here is about protection - not
> from interference, but from potential competition.
Not at all. You are simply ignoring what you don;t want to hear.
Bert
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