How far does the HD signal travel compared to the analog signal? - AVS Forum
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post #1 of 10 Old 01-29-2007, 01:17 PM - Thread Starter
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Hi. I've read that the HD signal only travels 60% of the distance that the analog signal does. Is there any truth to this.

Also, does the HD2 signal travel less than the distance of the HD1 signal?
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post #2 of 10 Old 01-29-2007, 01:32 PM
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It's a matter of how much power the signal has!
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post #3 of 10 Old 01-29-2007, 01:43 PM - Thread Starter
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Well yea, but that was my question, How much power does the HD signal have?
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post #4 of 10 Old 01-29-2007, 01:43 PM
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Most HD-2 stations travel the same distance as HD-1 stations, because they each use 48k of the 96 primary subcarrier. There is an additional set of (lower power) subcarriers which some stations use to broadcast an HD-3 station. These are more limited in range.

It is also possible to have a 96k HD-1 channel taking up the main subcarrier, and a low bitrate HD-2 channel taking up the secondary subcarrier, but I believe this is extremely rare.

As for range, I do not quite know the answer, but I know multiple people on this board have reported reception of HD stations over 100 miles on a consistent basis, so I would presume it goes pretty far. When factoring "range," you also have to consider reception equipment and conditions. A Sangean HDT-1 and a large outdoor yagi (APS-13 or HD-6065) are going to do a better job than a car radio and a whip.

http://rochestermnhd.blogspot.com/ - Tech 55901. Tech news for Rochester. Authored by mattdp and gjvrieze.
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post #5 of 10 Old 01-29-2007, 01:44 PM
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Quote:
Originally Posted by dead of night View Post

Well yea, but that was my question, How much power does the HD signal have?

Generally 1/10th of the stations analog ERP (for the main subcarrier) and considerably less for the secondary subcarrier.

http://rochestermnhd.blogspot.com/ - Tech 55901. Tech news for Rochester. Authored by mattdp and gjvrieze.
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post #6 of 10 Old 01-29-2007, 02:55 PM
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I've found that if the noise level in the analog signal is low enough to enjoy a station in FM stereo with no multipath, you should be able to receive the IBOC carriers without dropouts. I get about 18 stations using a 10 element outdoor antenna and am located about 32 miles away from them with a mountain between them and my house.

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post #7 of 10 Old 01-30-2007, 06:58 AM
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Bob's right (in my experience). If analog FM Stereo is completely clean (not "blended", and fully quieted), then you should get the HD.

By the way...HD power is 1/100th of the analog signal, not 1/10th. A 100,000 watt station has a 1,000 watt HD signal. Don't worry, this is comparing apples and oranges. HD doesn't need to be received "cleanly" (free of what would be analog noise). All that's necessary is that the radio be able to tell the difference between a one and a zero. THAT requires FAR less power.
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post #8 of 10 Old 02-03-2007, 05:18 AM
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I just put up an antenna, a Winegard HD6065P and the difference between the antenna that came with the accurian and this is night / Day. Before, I could only receive 3 channels that were 12 miles away but now have over 30+ station that are upto 50 miles away. All I can say is WOW, but what else would you expect with a 10' long antenna. AND YES, I live on a large hill, not sure if I have LOS to these towers, but not really caring since I am happy.

Jim

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post #9 of 10 Old 03-27-2007, 04:17 PM
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Quote:
Originally Posted by Bob Smith View Post

I've found that if the noise level in the analog signal is low enough to enjoy a station in FM stereo with no multipath, you should be able to receive the IBOC carriers without dropouts. I get about 18 stations using a 10 element outdoor antenna and am located about 32 miles away from them with a mountain between them and my house.

Bob Smith

At home I have my HDT-1 hooked up to the supplied dipole antenna and it is currently picking up 17 HD stations. 15 of them are multicasting. I can also pick up about 10 or so stations not in HD. I have done a little work to find that I have every radio station withing listening distance, and even a few in San Diego.

But I am not sure if that is typical or not. All I know is that the HDT-1 dial is filled with stations from the bottom to top. Even more stations than I knew even existed in the area.
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post #10 of 10 Old 03-28-2007, 05:24 AM
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I just noticed a couple of mistakes in this thread. One...HD is 1/100th the power of analog, not 1/10th. But this isn't that important, because NOISE isn't the concern that it is with analog. All the radio needs is to be able to distinguish a one from a zero...which requires much less power.

Also omeone said that power was the determining factor for coverage. It's only one of them, and not necessarily the most important one. The presence of first adjacent channels is probably more of a limiting factor.

And finally someone equated bitrate with power. 48k is a measure of BITRATE (the number of bits per second for the stream..in the case of 48k it would be 48 thousand bits per second, or 48 kilobits per second), not the power of the HD signal. If you receive HD1, you should receive HD2 (if present) as well. The bits are interleaved...a part of ONE signal, not a "separate subcarrier". That's analog thinking
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