Perfect line of sight required for OTA? - AVS Forum
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post #1 of 10 Old 04-25-2002, 09:16 AM - Thread Starter
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I have used Delorme to look at the profile between my location and the two main San Diego transmitter sites (Mt. Soledad and Mt. San Miguel). The transmitters are at 8.9mi (Soledad) and 25.4mi (San Miguel). I am on the downside of a ridge (about 1/2 mile from me) that separates me from both transmitters. The ridge is about 100/180' higher than my house depending on the transmitter. Is there any hope?
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post #2 of 10 Old 04-25-2002, 10:39 AM
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Plenty of chance you can get good reception. Without line of sight it just gets much more difficult.

Worst case would be if you have no line of sight, and other hills around that see the full signals and reflect at you from various directions.

You need a more directional antenna as well as more gain than you would need in a good location. And some places are maybe impossible, but very few.

I lose maybe 30 db of signal at 12 miles from my local stations. There is a hill about a mile from my house that blocks the signals and is just about 200 feet too high.

I also have the reflecting hills problem, so I need a dual antenna horizontal stack to get all stations reliably. A regular antenna would only get me 5 out of 6.

With lots of multipath moving a few feet sideways can make big differences, and indoor antennas tend to be quite useless.
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post #3 of 10 Old 04-25-2002, 11:06 AM
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i too am on the downside of a ridge which is aprox 150' to 200' higher than my house. the transmitter is aprox. 5 to 6 miles away with no other obstacles. i get perfect reception at 95 to 100 strength using an $18 indoor radio shack bowtie antenna that sits on top of my tv.
good luck, john
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post #4 of 10 Old 04-25-2002, 05:07 PM
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Pumori,

What are you receiving now on the analog UHF channels 35 from Soledad; 39 or 51 from San Miguel; and 21, 27 or 33 from San Antonio?

I concur with jhe that your reception will vary by the inch, and I was able to talk someone in Carlsbad through just such a problem. He's a very satisfied customer now.

Your mileage may vary.

Gary Stigall, Sr. Engineer, KFMB-TV/DT CBS San Diego
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post #5 of 10 Old 04-26-2002, 07:24 AM - Thread Starter
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john's situation gives me hope. I will pick up something like a RS double bowtie and test it with the analog UHF channels mentioned by BlueWire (this would be in the attic to start). I am assuming that if I can get some solid signals from these analog stations the next step is buying a STB and giving it a shot (I will have to examine the return policies *very* carefully!).

Thanks for the input.
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post #6 of 10 Old 04-26-2002, 07:07 PM
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Note that, when looking at the profile, be sure to account for the height of the transmitting antenna. You can find this information on the FCC website at http://www.fcc.gov/mb/video/tvq.html . Look for the Ant. Radiation Center Above Mean Sea Level (RCAMSL) figure, which gives the altitude of the antenna in meters. Things may not be as bad as you think they are.

You have a right to install OTA and dish antennas on property under your control.
See http://www.fcc.gov/mb/facts/otard.html
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post #7 of 10 Old 04-27-2002, 07:00 AM
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Site that BarryO mentioned works, but a perhaps easier one to use (easier on the eyes for sure) is (http://100kwatts.tmi.net/).

HNick
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post #8 of 10 Old 04-27-2002, 01:01 PM
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Or, if you're not into bookmarks, just remember http://www.100000watts.com/

Sean Kelly / Independent Consultant
http://www.seankelly.tv/
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post #9 of 10 Old 04-27-2002, 07:21 PM
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Careful with 100Kwatts.com. The height info listed there is Height Above Average Terrain (HAAT), and is not necessarily the elevation of the transmitting antenna.

You have a right to install OTA and dish antennas on property under your control.
See http://www.fcc.gov/mb/facts/otard.html
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post #10 of 10 Old 04-28-2002, 11:17 AM
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FYI, hopefully a helpful tidbit that'll keep you from digging in the Encylopedia, Multiply the RCAMSL figure from the FCC site by 3.28084 to convert Meters to Feet Above Sea Level ...

Jeff
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