Difference between satellite HD signal, and OTA HD signal? - AVS Forum
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post #1 of 10 Old 07-25-2006, 03:44 PM - Thread Starter
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Is there any difference -- in picture quality -- between antenna received HD, and satellite dish (DirecTV) HD?

So far my local HD channels don't look as sharp and crisp, as say, ESPNHD and DiscoveryHD...but maybe that's just because the programs I viewed weren't made for hi-def :confused:


I guess I'm just wondering if my OTA antenna is good enough. I get good reception, in that I don't get any static, wavey lines, or breaking up of the picture. I'm just wondering if I'm getting the best HD picture possible out of my locals... If I'm getting a good signal, is that all I need to be concerned with?

Thanks. :)
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post #2 of 10 Old 07-25-2006, 04:04 PM
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Much of the material on a broadcast HD channel is actually SD, upconverted to HD by adding pixels. The quality can vary a lot, especially for locally-originated material such as local news and syndicated shows. It depends on the quality of the source material and the software/hardware that the station uses for upconverting. On one of my stations, local news, Jeopardy and Wheel of Fortune look very crisp with bright colors. On another station, local news and reruns such as Everybody Loves Raymond look like crap: fuzzy and with washed-out, dingy colors.

SD material from the networks (reality shows etc.) also varies in quality. Some networks (like NBC I think) upconvert that material themselves and send it out on their HD feed, and it usually looks pretty good. Other networks (like CBS) make local stations upconvert that material, so it depends on the equipment that they use.

True HD should generally start out looking very good. But the final quality depends on how much bandwidth (bits per second) the provider uses in broadcasting it. Some broadcast stations devote more of their bandwidth to subchannels for weather, music videos, etc., than other stations do. DirecTV also reduces the bandwidth so they can transmit more channels. A lot of people on these forums complain about "HD-Lite" from DirecTV as a result.

Assuming you can get a stable OTA signal, it should be no worse than the same channel on DirecTV, because DirecTV gets the signal from the station to begin with (either by picking up the broadcast feed or by fiber-optic link or something). In many places it will probably be better than the DirecTV feed.
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post #3 of 10 Old 07-26-2006, 01:14 AM
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Quote:
Originally Posted by iLLWiLL
Is there any difference -- in picture quality -- between antenna received HD, and satellite dish (DirecTV) HD?

So far my local HD channels don't look as sharp and crisp, as say, ESPNHD and DiscoveryHD...but maybe that's just because the programs I viewed weren't made for hi-def :confused:


I guess I'm just wondering if my OTA antenna is good enough. I get good reception, in that I don't get any static, wavey lines, or breaking up of the picture. I'm just wondering if I'm getting the best HD picture possible out of my locals... If I'm getting a good signal, is that all I need to be concerned with?

Thanks. :)
Make sure you are watching the digital version of a local channel and not the analog version.

If you watch something like a good, PBS-HD program, or Letterman or Leno in HD at night, the broadcasts should look fantastic.

If they don't look as good as (or better than) your satellite HD channels, then something's not right.
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post #4 of 10 Old 07-26-2006, 06:09 AM
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Quote:
Originally Posted by Rammitinski
Make sure you are watching the digital version of a local channel and not the analog version.

If you watch something like a good, PBS-HD program, or Letterman or Leno in HD at night, the broadcasts should look fantastic.

If they don't look as good as (or better than) your satellite HD channels, then something's not right.
A digital channel has a suffix, so channel 4 is analog, 4.1 is the digital equivalent.
Normally HD OTA material will be at least as good as the same material broadcast via satellite or cable, as those need to reprocess it.
If you are getting a digital OTA picture that is not breaking up then that is as good as it will get. (OK, not strictly true but close enough).

So to summarize;
1) Are you tuned to a digital OTA channel (ie does it have a suffix)?
2) Is the picture steady and not breaking up?
3) Was the material broadcast in HD? (Remember all HD is digital but not all digital is HD).
4) Was the material originally recorded in HD before broadcast? As Ramitinski stated, something like Letterman which is definetly in HD, is a good test.
5) Do you have a suitable connection between the tuner and the TV - HDMI or component?
6) Is the tuner set to output in an HD resolution that matches the TV?
7) is the TV set the correct input?

87% of statistics are inaccurate
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post #5 of 10 Old 07-26-2006, 06:09 AM
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HD satellite vendors do compress their HD downfeeds and OTA broadcasters usually do not. A true HD broadcast can be spectacular. Our local NBC station broadcast the Olympics in full 1080i, they turned off their multicast .2 and .3 channels, and the true HD portions of the Olympic coverage were outstanding. It is not really fair to compare SD with true HD, although most networks and cable/satellite vendors do "mix" the feeds.

Even digital SD broadcasts from over-the-air broadcasters look better on a large screen TV than the same program on satellite
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post #6 of 10 Old 07-26-2006, 09:05 AM
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As stated above, the satellite comparison to OTA will depend on how much the satellite company compresses the signal. It can vary quite a bit depending on how much bandwith they give it at any particular time.
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post #7 of 10 Old 07-26-2006, 12:10 PM - Thread Starter
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wow, very in-depth responses! Thank you, everyone! :)


my signal is fairly good, i suppose. I was watching Conan O'Brien last nite, and i could NOT believe my eyes. :eek: That was the BEST picture I've ever seen in my life. (Plus, Rosario Dawson was on, so the picture EXTRA beautiful, haha ;))


the picture DID however break up for a few seconds, though. I checked my signal strength, and it would bounce between 88% to 98% on the regular...
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post #8 of 10 Old 07-26-2006, 06:17 PM
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Quote:
Originally Posted by iLLWiLL
wow, very in-depth responses! Thank you, everyone! :)


my signal is fairly good, i suppose. I was watching Conan O'Brien last nite, and i could NOT believe my eyes. :eek: That was the BEST picture I've ever seen in my life. (Plus, Rosario Dawson was on, so the picture EXTRA beautiful, haha ;))


the picture DID however break up for a few seconds, though. I checked my signal strength, and it would bounce between 88% to 98% on the regular...
Sounds like some of the programs you watch aren't in HD, or you're local station isn't broadcasting in HD.

btw, it helps to put your location in your profile.

Currently testing 3D with Sammy DLP, shutter glasses, and HTPC
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post #9 of 10 Old 07-26-2006, 06:50 PM
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Quote:
Originally Posted by iLLWiLL
the picture DID however break up for a few seconds, though. I checked my signal strength, and it would bounce between 88% to 98% on the regular...
There are at least three possible causes for such "bouncy" behavior:

1. Multipath interference - the signal is reflecting off something "nearby" and interfering with the main signal. This can often be reduced by moving the antenna. It's common with indoor antennas, in which case moving the antenna outside helps a lot (and makes the main signal stronger too).

2. Impulse-noise interference - especially if the digital signal is actually being broadcast on a VHF channel (2-13) - caused by bursts of electrical "noise" from poorly shielded motors, appliances, power lines, etc. To check this, use an analog VHF tuner, and tune to a VHF channel that is being used for analog TV in your area. On analog TV, it shows up as white speckles, often in bursts that look like horizontal bands of snow. I don't know if there's anything you can do about it except get rid of the noise sources.

3. A weak signal from a distant station, near the borderline of your antenna's abilities. When it drops a bit below the borderline because of atmospheric fluctuations, the picture breaks up. (Decoding a digital signal is pretty much an all-or-nothing affair.) Putting a pre-amp on the antenna can sometimes help, but the best solution is a better antenna, or switching from an indoor to an outdoor antenna.
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post #10 of 10 Old 07-27-2006, 06:09 PM
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Quote:
Originally Posted by jtbell
There are at least three possible causes for such "bouncy" behavior:

1. Multipath interference - the signal is reflecting off something "nearby" and interfering with the main signal. This can often be reduced by moving the antenna. It's common with indoor antennas, in which case moving the antenna outside helps a lot (and makes the main signal stronger too).

2. Impulse-noise interference - especially if the digital signal is actually being broadcast on a VHF channel (2-13) - caused by bursts of electrical "noise" from poorly shielded motors, appliances, power lines, etc. To check this, use an analog VHF tuner, and tune to a VHF channel that is being used for analog TV in your area. On analog TV, it shows up as white speckles, often in bursts that look like horizontal bands of snow. I don't know if there's anything you can do about it except get rid of the noise sources.

3. A weak signal from a distant station, near the borderline of your antenna's abilities. When it drops a bit below the borderline because of atmospheric fluctuations, the picture breaks up. (Decoding a digital signal is pretty much an all-or-nothing affair.) Putting a pre-amp on the antenna can sometimes help, but the best solution is a better antenna, or switching from an indoor to an outdoor antenna.

4. The exciter the station is using is having problems. Our station had these types of problems. At home, the signal would flux between 85% and 100%, but I would get a lot of drop outs. Turns out, one of the cards in the exciter was bad.

It's since then replaced, but it seems we have to do a reboot about once a month, or else it'll start acting up again. We're still trying to figure out exactly what is causing it.

Currently testing 3D with Sammy DLP, shutter glasses, and HTPC
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