Re: State of OTA DTV in Tucson? (kinda long, sorry!)
Sporque said:
Thanks, I didn't know about powered antennas being problematic for DTV.
I bought one because of HOA issues at my condo- reception from an indoor antenna is pretty poor with all the wiring and plumbing
and I can't mount an outdoor mast.
Just so you know, your HOA cannot prevent you from installing an outdoor antenna in locations under your exclusive control. See
http://www.fcc.gov/mb/facts/otard.html.
Of course, what's legal and what will keep you on speaking terms with the neighbors may be two different things.....
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What does your *analog* reception look like with an indoor antenna?
A powered antenna helps with "snowy" reception - weak signals. If you have "ghosts" - multiple images - a powered antenna will not help. If you live in the city of Tucson it is very unlikely you have a problem with weak signals.
To amplify (sorry!) on Scott's comment about powered antennas being trash... The older multi-element antennas strengthen signals by more efficiently collecting the available signal. They do so by concentrating their response in the direction they're pointed. (i.e., at the transmitting tower) Doing it this way has a side effect: these multi-element antennas receive rather poorly in directions other than the one in which they're pointed. This is a Good Thing, because not only do these antennas more efficiently receive the signals you want, they also reject interference. Or, in the case of "ghosts", they reject unwanted copies of the desired signal bouncing off mountains/buildings/your refrigerator.
Powered antennas receive more or less equally well in all directions. They then try to strengthen signals with an amplifier. The problem is that the antenna itself is picking up not only the desired signal, but unwanted interference and "ghosts" coming from other directions. The amplifier then boosts all these undesired signals right along with the desired signal.
But there's more.
What does an amplifier do? It strengthens an incoming signal. If you have an amplifier with a gain of 10, and you apply a signal of 1/10 volt to the input, you get a signal of 1 volt on the output.
In digital TV, the station transmits eight discrete signal levels. (hence "8VSB") Let's say that those eight levels, as received on your antenna from KGUN-DT, are 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8 volt. You have an amplifier with a gain of 10, powered from a 6-volt power supply.
Code:
[b]Number Input signal (volts) Output signal (volts)[/b]
1 0.1 1
2 0.2 2
3 0.3 3
4 0.4 4
5 0.5 5
6 0.6 6
7 0.7 [b]6[/b]
8 0.8 [b]6[/b]
The amplifier can't possibly put out more than 6 volts, because that's all the more that's coming out of the power supply that powers it. So the signal coming out of the amplifier is the same for signal levels 6, 7, and 8 - your DTV can't tell the difference. As a result, 25% of the data you receive will be in error. The DTV standard can fix some reception errors, but it can't deal with 25% of the data being wrong.
Point is, an amplifier is not only useless in a city where signals are already strong, but it can actually make reception
worse.
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Looking at the FCC Database, the only Tucson channels I see operating at low digital power are 27, 40, and 46. Of course 27's
analog is pretty weak too. (and they have no current plans to increase digital power) 40 has a permit to increase their power by roughly a factor of 30 when they change frequency on the 18th. 46 has a permit to increase by a factor of about 5 when
they change frequency. It may be worthy of note that channels 11, 13, and 18 have their analog transmitters at a different site from channels 4, 6, and 9 - but all six stations are transmitting digital signals from the same site. (the existing 4/6/9 analog site)
I don't see any evidence that any of the Tucson stations (except 27?) ever transmitted DTV from their studio sites, though that was common practice in some other markets. Some did have reduced-power permits but with the exception of the three mentioned above those permits have been superceded by full-power operation.
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MyFacedotcom said:
As mandated by Congress, Feb. 17 will be the last day for full-power television stations to broadcast in analog. Afterward, they will broadcast in digital.
I don't think analog will be an option for anyone.
A week ago I would have agreed fully
There is a move afoot in Congress to delay the transition by 6-12 months. President Obama supports this move and I think we can assume he'll sign such a bill if it passes Congress. There is however considerable opposition in Congress and it is by no means certain a bill will be sent to the President.
What
has passed Congress and been signed by outgoing President Bush is the
Analog Nightlight Act. The FCC released the implementing rules last Friday.
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-09-2A1.pdf.
This Act allows some (many) analog stations to operate until March 19th, but only to broadcast information about the DTV transition, and information on any emergencies that may occur during the nightlight period.
The FCC action includes a list of stations initially eligible to participate. In Tucson this list includes channels 3, 4, 6, 11, 13, and 27. These stations can participate by merely notifying the FCC. Four other stations - channels 9, 18, 40, and 46 - can participate if they can prove they can leave their analogs on the air without interfering with anyone else's digital. (possibly by operating at reduced analog power) (I doubt they'll bother)
