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  #11  
Old 10-13-2010, 02:26 PM
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Quote:
Originally Posted by Hulk
Do you need less signal strength with digital or is the same strength needed?
Digital TV is obviously a digital mode. Think back to your ham knowledge, what is a primary advantage of digital modes, such as CW (Morse), PSK31, etc.? Higher signal to noise ratio. So yes, digital TV reception can tolerate a more marginal signal and still get an acceptable picture. The old U.S. standard was NTSC, which is essentially a multiple signal AM mode.

The need for a lower signal strength works in favor of the broadcaster, too. They might be using lower power transmitters now so that an individual TV that had an OK picture before will still have an OK signal now. When you are talking about replacing a 500 KW xmitter with a 100 KW, that's a major savings in electricity. If that means a typical TV used to need -20dBm to get a good picture and can now deal with -35dBm, they'll be happy to lower their power.
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Originally Posted by Uncle Ben View Post
Digital signals are short compared to the old analog signals.
Digital TV broadcasts still reside in the VHF-low, VHF-high and UHF bands. Most of the channels that were in the VHF-low have moved to VHF-high and UHF, so you don't need the super big antennas anymore. The bulk of TV here in Denver now sits at about 174-215 MHz and 470-650MHz. A dipole with length of about 31.44" and 12" is about right for Denver.

http://en.wikipedia.org/wiki/North_A...on_frequencies

The reason for the FCC push to ATSC was that each channel can take up less bandwidth now and so some of the old analog spectrum has been reallocated. But the channel centers haven't all moved to UHF and so most of the same propagation limits still exist like before.
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  #12  
Old 10-13-2010, 02:50 PM
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Quote:
Originally Posted by DaveInDenver View Post
Digital TV is obviously a digital mode. Think back to your ham knowledge, what is a primary advantage of digital modes, such as CW (Morse), PSK31, etc.? Higher signal to noise ratio. So yes, digital TV reception can tolerate a more marginal signal and still get an acceptable picture. The old U.S. standard was NTSC, which is essentially a multiple signal AM mode.

The need for a lower signal strength works in favor of the broadcaster, too. They might be using lower power transmitters now so that an individual TV that had an OK picture before will still have an OK signal now. When you are talking about replacing a 500 KW xmitter with a 100 KW, that's a major savings in electricity. If that means a typical TV used to need -20dBm to get a good picture and can now deal with -35dBm, they'll be happy to lower their power.
Thanks, Dave. You confirmed what I thought concerning lower signal strength. And you added something I hadn't considered: reduced transmitter power.

I'm going to give an antenna a try, I think. I like DIRECTV just fine, but the cost is high compared to how much we actually use it.
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  #13  
Old 10-13-2010, 03:03 PM
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Quote:
Originally Posted by Hulk View Post
Thanks, Dave. You confirmed what I thought concerning lower signal strength. And you added something I hadn't considered: reduced transmitter power.

I'm going to give an antenna a try, I think. I like DIRECTV just fine, but the cost is high compared to how much we actually use it.
We gave up DirecTV a few years ago for the same reasons and with analog TV + Netflix DVDs it wasn't too bad. Now with DTV + Netflix DVDs and Streaming + Hulu it's even less of an issue. The only thing cable/DBS gets you is a lot more sports, but even that I just head down to the bar to watch the Buffs (who are generally on Fox Sports or ESPN). Yeah, with all the hassle they got over the towers on Lookout I'm sure lower powers would be something they would love. Caveat: I don't know that they are lower power, just speculation.
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Old 10-13-2010, 04:58 PM
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we got a antenna that we brought from Costco ($49.00) that is pretty small on the side of our ranch in Castle Rock. We get all the signals, even during storms. I agree, I hate paying for TV and most of the stuff on cable is junk.
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Old 10-13-2010, 05:30 PM
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I would love to keep my 80 bucks a month vs. give it to Direct TV, but I love DVR......watching this thread very carefully even still.
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  #16  
Old 10-20-2010, 01:00 PM
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Excuse the dumb question.

I have been asking some of my neighbors whether they are using antennas in their attics. Several of them have said, "You need a digital antenna now."

My thought has been that a yagi antenna shouldn't work any differently whether the information received is analog or digital as long as the frequency hasn't changed. Right?

Another reason that I ask is that a friend in another neighborhood has a big antenna on her house that she isn't using. I can probably get it for free.

I know this seems like an idiotic question. Sorry.
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  #17  
Old 10-20-2010, 01:46 PM
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Old TV antennas were designed to receive UHF and VHF analog signals. Digital TV goes out on the UHF spectrum, so newer antennas are now optimized for this.

My old rooftop antenna (with amplifier) works great for Digital (and analog) TV. You're fine with an old rooftop antenna, in my opinion, as long as it's not corroded or in poor shape.
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  #18  
Old 10-20-2010, 01:46 PM
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EM waves don't care if your 175MHz carrier is modulated with analog or digital information. The marketing of 'digital' antennas is just to capitalize on the confusion.
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  #19  
Old 10-20-2010, 01:56 PM
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Quote:
Originally Posted by SteveH View Post
Old TV antennas were designed to receive UHF and VHF analog signals. Digital TV goes out on the UHF spectrum, so newer antennas are now optimized for this.
No, no, no!

Sorry. :-)

Digital TV does use more UHF spectrum than we used to, but a lot of TV still resides in high band VHF. So in that sense you might need a better UHF antenna (e.g. wider bandwidth potentially), but several stations are still in the 174-215MHz region just like before. For example channel 9 up here in Denver (KUSA) was on the old analog 9 at 181MHz but is now at digital 9 at 187 MHz. OTOH, some of the very high end UHF analog stations lost their spectrum, so a number of channels 52 and higher actually went down in frequency and are now easier to receive with existing UHF antennas that were optimized for analog channels 14 to 50. For example the old channel 59 in Denver went to RF 43, which means it's much closer to channel 31 and so comes in stronger than before with my marginal UHF loop that I tuned for FOX31 (I love The Simpsons!).

Now down in the Springs it is true that (I think) all of your major networks are now on UHF. So for you having no VHF only means you might lose PBS or something.
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  #20  
Old 10-20-2010, 02:09 PM
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The one I ordered from Channelmaster is for UHF and VHF high. Hopefully they won't be moving any channels into VHF low.

Speaking of Channelmaster.... The first antenna arrives and the box is split open. It appears that the hot melt glue didn't stick very well. I open the rest of the box and all of the parts are there, nothing fell out of the open box. So I go to unfold the array and a piece falls off in my hand. A plastic insulator that is part of the connection terminal is cracked. So I call up Channelmaster and inform them of the damage. The send me another antenna.... the second box a arrives split open and the plastic terminal is broken in the same place. I don't think the crack is due to the box failure but more likely an assembly rivet is crushed down too far cracking the plastic. I talked to them again but they haven't decided what to do yet. This is get annoying. I'll see what they can do to make me a happy customer. Gluing the plastic back together should fix it but I shouldn't have to do this. Its a good thing the old antenna is still functional.
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