[opendtv] Re: A Clue re OTA DTV users: How many OTA?

  • From: Richard Hollandsworth <holl_ands@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Thu, 14 Dec 2006 16:15:25 -0800 (PST)

Can't very well simply broadcast all of those cable channels via OTA without 
some form of payment--which means a decryption device (e.g. STB or DCAS) for 
each DTV to limit access--and maybe a different STB or DCAS key for each OTA 
multiplexed service provider....which would require monthly service charges.....

Hmmm, seems to be the same as a monthly cable bill.....why bother....esp. given 
the difficulties of providing RELIABLE service from a fairly large number of 
(usually widely dispersed) broadcast towers....

Even if you somehow worked out a funding model for FREETV (ala U.K.'s "TV Fee" 
scheme ???), only certain "family friendly" channels would pass the FCC's 
"decency" criteria--excluding Comedy Central, Travel Channel, TNT, USA, WGN 
(Sex&City), MTV, Spike, and perhaps CourtTV, A&E, E!, etc.

How many OTA stations can co-exist in an extended Metro environment?
Let's look at the "quick list" for NYC and L.A. found at fol. website:
noting that there is overlapping coverage to some adjacent Metro areas in 
adjacent states....
also noting that there is overlapping coverage from San Diego, Santa Barbara 
and Palm Springs areas.

Yup, they've used nearly every channel position if you consider the extended 
range overlap of VHF and CH37 is reserved for radio astronomy.

Since about half of these are analog channels, you would think that lots of 
channel positions would open up--but Distributed Transmitter Networks could 
chew up a bunch of assignments--and I'm predicting that many of the old NTSC 
transmitters will somehow be turned into new, bargain basement DTV stations, 
rather than becoming a glut on eBay.  Other than being modified for DTV with a 
new exciter (whether ATSC or DVB-T or whatever) and other mods, who would want 
an obsolete NTSC transmitter and antenna structure anyway...

When NTSC goes away, the adjacent and co-channel interference problems will be 
less severe with only DTV vs DTV (give or take some unlicensed device issues), 
making it somewhat less problematic to assign channels.  Indeed, note that 
there are MANY adjacent channel assignments now, over and above the common use 
of adjacent assignments for a single station to employ a combined NTSC/ATSC 
transmitter/antenna system.

There will be only 49 channel positions left as the channels above CH51 are 
reshuffled.  Hence the remaining VHF/UHF channel spectrum will be able to 
sustain a total of 49 DTV channels x 19 Mbps = 931 Mbps.

My current TWC-San Diego system has 84 analog TV channels + about 152 digital 
TV channels (carried on 35 QAM-256 digital TV channels) for a total of 119 
channel positions for "broadcast" TV video.

There are about 236 unique TV channels currently supported on TWC-SD (84 
analog, 20 HD and 132 SD), excluding PPV, Free OnDemand and the duplicative 
Digital Simulcast carriers.  TWC-SD currently packs two (1080i) or three (720p) 
HD per QAM-256 carrier and as many as 13 SD per QAM-256 carrier.

If we assume a max of 6 SD channels or (one HD + two SD) channels per ATSC 
carrier (the best I've ever seen in actual use), then it would take 50 ATSC 
channels to carry the same load....which clearly exceeds the number of 
available channels.

If the recent claim of 2 HD + 1 SD per ATSC carrier is really WATCHABLE, with 
perhaps 8 SD per carrier, then it would take "only" 35 ATSC channels.....good 
luck getting that many new assignments....even if you can convince some legacy 
stations to join your multiplex....

But that only keeps up with the CURRENT HD/SD mix.  In a couple years, many 
more HD channels are expected to become available (D* sez 150 National HD, 
which I think means 50 HD per time zone)....which would need all 49 ATSC 
channel assignments for both SD and HD....

By Feb2009, TWC-SD will probably be all-digital (analogs are already a Digital 
Simulcast), for a total of 119 QAM-256 x 38 Mbps = 4294 Mbps available for TV 
Video (incl. Radio/Music Choice).

Note that currently there are (at least) an ADDITIONAL 9 channels below 759 MHz 
that presumably are used for PPV, Free OnDemand, Internet Service (1 shared QAM 
channel), VoIP phone service (very low data rate), HDTV software updates, et. 

Cable Systems start with an inherent 2:1 data rate per 6 MHz channel advantage 
(QAM-256 vs 8VSB).  And by simply deleting some (and eventually ALL) of the 
analog channels, their capacity can easily accommodate the 4:1 increase in data 
rate needed to add HD channels.

And when Switched Digital Video is employed so that infrequently used channels 
are only sent down a sub-set of shared QAM carriers when a user in a 
neighborhood actually requests them, a nearly UNLIMITED number of "niche" (aka 
unpopular) program requests could be supported via ala carte program selection 
(putting NetFlixs out of business)....

BTW: Verizon FiOS uses a SINGLE FIBRE to deliver the ENTIRE 55-870+ MHz wide 
cable spectrum (analog + QAM, just like cable) via a 1550 nm laser, plus 622 
Mbps (shared) voicce/data downlink via 1490 nm laser plus 155 Mbps (shared) 
voice/data uplink via 1310 nm laser.  Just image what they could do with 
multiple fibre cables.....


flyback1 <flyback1@xxxxxxxxxxx> wrote: 
It occurred to me just now it might be time to ask a basic question.

How many digital OTA television stations would have to built in 
Philadelphia or, if you wish,
each and every market in the US to cover each market with all the same 
number of SD and HD
programs now available in those markets over cable or satellite?

Is the FCC's allotment of channels market by market sufficient to 
accomplish such a task,
or would there be adjacent and co-channel interference from one market 
into another, not to mention
within the same market that would stop the process cold? 

C'mon, somebody choose a market they are familiar with and tell me how 
many digital stations it would take
to provide all the channels available on cable or satellite.

If it WERE technically possible, would it be economically feasible to 
attempt such a massive venture?


If not, is it because cable and satellite are much more efficient 
technically and economically when providing
several hundred channels some which interactive, to each customer?

If digital OTA can't provide the wealth of programming that cable or 
satellite can in any given market,
why are we wasting time and money with 8VSB, ATSC,  arguing about it,  
searching for the grail
of set top boxes,
instead of holding a really great OTA WAKE with weeks of parties, lots 
of booze and hors derves,
and finally, in the end, toppling over all the towers to protect the birds?

Bob Miller wrote:

> On 12/13/06, Manfredi, Albert E  wrote:
>> > The article quotes an increase from 10M homes this year to 24M
>> > homes in four years going to HDTV. So guess what that says about
>> > OTA users?
> The number of OTA users will go up but the percentage of all with HD
> content will go down. When the dust settles it will be 2%. This will
> represent those who both want HD and only want to receive it OTA.
> A lot of people will want to receive TV OTA but that demand will be
> filled more and more by new broadcasters using other spectrum like
> channels above 51 and wireless broadband.
> Opps! Forgot, should include present TV spectrum below 51 also since
> WiFi and its cousins will be allowed to use that spectrum also with
> smart radios.
> Bob Miller
>> To be absolutely clear: these numbers refer households actually watching
>> HDTV. Not just owning an HD-capable set.
>> Bert
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