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Old 30-Sep-2014, 3:21 AM   #1
cleverpig
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Trees causing reception issues

I have recently moved and need assistance with an OTA antenna configuration for my situation. I am in Columbia, SC in a one story ranch home situated on a small lake in an old neighborhood. The terrain includes some rolling hills with lots of trees many of which are large and very tall pines. Here is the link to the signal analysis for my location. http://www.tvfool.com/?option=com_wr...d243840e7e7f51

You will see that there is a cluster of five transmitters on three towers located 12 to 13 miles away at an azimuth of 63 to 70 degrees (real channels 8, 10, 17, 39 & 48). The PBS affiliate, channel 32, is 5-1/2 miles away at 11 degrees. The analysis indicates this is line of sight but in reality there is a 100’ high hill on this path ½ mile away that is covered with houses and thick tall trees. While channel 47 is only 2.4 miles away at 277 degrees we have no interest in watching it but it will likely be received well on the back side of anything pointed at the cluster to the east.

I have temporarily installed a Channel Master 3010 Stealthtenna in my attic and at most times get decent reception on 8, 10 & 17. Channel 32 is hit or miss. Channels 39 & 48 are not received at all. Wind negatively impacts reception causing loss of 32 and poor reception on the other three. I bought the CM 3010 to use at my previous residence which was about 4 miles to the south but had the same issues even with it roof mounted. This compact antenna just has too little gain to work in this situation. I ended up installing an old channel 10 yagi pointed at the cluster along with a 4 bay bow tie UHF array pointed about half way between the cluster and 32. This arrangement worked great providing sufficient gain such that I needed no amplification even after combining the antenna signals and splitting it to feed two TVs.

In the new location I would really like to mount the antennas in the attic both for aesthetics and to shield the antennas from debris that fall from the surrounding trees. If necessary I will roof mount them but would need to select antennas to minimize the visual impact. We will have three TV’s to distribute the signal to. My first thought is to install a VHF-high/UHF yagi pointed toward the cluster and a separate UHF antenna pointed to 32. Another alternative would be to use a VHF-high yagi pointed at the cluster and a UHF antenna with a wide beamwidth pointed somewhere between the cluster and 32 similar to my arrangement at the previous house. If helpful the two antennas could be spaced some distance apart.

The signals from the two antennas would be combined and then amplified for distribution to the three TVs. I have a Winegard model HDP-269 preamplifier with 12dB gain designed to handle high inputs. It includes an FM trap. I also have an old Channel Master model 7336 82 channel UHF/VHF/FM distribution amplifier with four outputs that I could use. The house already has RG-6 run from the attic where the antennas would be located to the TV locations.

Please provide recommendations with as much specifics as possible. Thanks in advance for your assistance.
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Old 30-Sep-2014, 4:53 AM   #2
StephanieS
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Greetings Cleverpig,

We often encourage people with their antenna(s) to get them above the trees. Why is this so? Trees reflect, attenuate and disrupt the signal before it gets to your antenna. The result can yield unreliable reception in situations where it should be a "slam dunk." Additionally, by mounting in the attic, you are further attenuating the signals and causing more multipath and can promote even less reliable reception because you are asking a compromised signal to be compromised more by penetrating your roof.

Mounting outdoors is very important, especially in this situation. An antenna can only work with the signal that is present. If the signal varies to a high degree, even the strongest gain antenna can't overcome a compromised signal.

Essentially tree obstruction + attic install is what you are asking any antenna to do. The result is you will likely continue to have reception issues and the situation will not be satisfactory.

Reconsider your mounting location to give yourself the best chance at reliable reception.
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Old 30-Sep-2014, 12:08 PM   #3
Stereocraig
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Unfortunately, aesthetics and visual impact as you put it, do not always coincide w/ proper performance.

The transmitters need to hit your antenna w/ enough signal to be properly translated by your tuner.

Having an antenna that's low, miniscule, or sheltered indoors, will all contribute to inferior performance.
You would then be out the time and money for a failed installation and still need to do the installation properly, if in fact it doesn't discourage you completely.

Do it right the first time and chuckle to yourself, every time you look at your beautiful picture, beautiful antenna and think about how much other people are flushing down the toilet on pay TV.
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Old 30-Sep-2014, 3:18 PM   #4
cleverpig
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Thanks for your quick replies.

Unfortunately, above the trees is not practical in my situation. I would have to have a hundred foot or more tower to get above the tall pine trees on my property not to mention the trees on adjacent properties at higher elevations. A rooftop installation may be my best and only solution. My main question is how to best receive PBS channel 32 which is about 55 degrees around from the cluster of other VHF and UHF channels we watch. Any suggestions on the type of antennas to use along with how to physically arrange and connect them would be appreciated. If I have two antennas what is the best way to combine their signals?

I have never used cable or satellite services and hope I never have to. The OTA reception I got at my previous residence with the rooftop installation I described proved the superiority of OTA over cable or satellite.
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Old 30-Sep-2014, 6:01 PM   #5
StephanieS
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I'm glad you are open to a rooftop installation. By mounting outdoors, you are improving your chances of reliable reception through your geographical and foliage obstacles. You may not have 100% reliability, due to the trees, but you are giving your antenna(s) a much more favorable situation to work.

From your description of your surroundings I would go a little stronger of a set up than would normally be required. This means a two antenna system. One for VHF channels on real 8 and 10. The other for UHF.

Antenna 1: Antennas Direct DB8e. Both panels aimed at magnetic 73
Antenna 2: Antennacraft Y5713 aimed to magnetic 71
Antennas Direct EU385CF mast mounted signal combiner.
Run single lead of coax into home to CM 3414 distribution amp.

I would not install a preamp. Instead I would favor the Channel Master 3414 4 port distribution amplifier to split the signal. There is a chance of enough signal being present that I'd rather the amplification be at the split rather than at the mast to avoid any potential overloading since the antennas would be pointed right at the signals you want in addition to that 70db CW signal. There are a few tolerant preamps that handle high inputs, however I wouldn't be comfortable installing a preamp with a 70db signal nearby.

Cheers.

Last edited by StephanieS; 30-Sep-2014 at 6:03 PM.
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Old 30-Sep-2014, 8:01 PM   #6
cleverpig
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Thanks Stephanie.

I am curious why you don't suggest pointing one of the DB8e panels at magnetic 19 to maximize the gain on channel 32 better? With 50+ degrees difference from the cluster of other transmitters and the relatively narrow bandwidth of the DB8e with both panels pointed in the same direction I would think the gain on channel 32 would suffer.
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Old 30-Sep-2014, 8:03 PM   #7
cleverpig
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Sorry. I meant narrow beamwidth not bandwidth.
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Old 30-Sep-2014, 8:20 PM   #8
StephanieS
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Ah yes, reading fast nails me again! I had read the report as the RF 32 PBS as having the same heading as the other channels.

You are absolutely correct in how to orientate the panels of the DB8e. One on the magnetic 72 cluster and the other towards WRLK at magnetic 19.

Cheers.
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Old 1-Oct-2014, 3:52 PM   #9
cleverpig
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As suggested by Stephanie I plan to install separate VHF-high and UHF antennas on my roof. Are there any recommendations on how to physically arrange the two antennas? I can install them on the same mast one above the other or mount them separately with horizontal distance between them. I don't know what kind of interaction I might get between the antennas. By using the recommended Antennas Direct VHF/UHF combiner will I minimize that interaction?
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Old 1-Oct-2014, 4:10 PM   #10
Stereocraig
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Quote:
Originally Posted by cleverpig View Post
As suggested by Stephanie I plan to install separate VHF-high and UHF antennas on my roof. Are there any recommendations on how to physically arrange the two antennas? I can install them on the same mast one above the other or mount them separately with horizontal distance between them. I don't know what kind of interaction I might get between the antennas. By using the recommended Antennas Direct VHF/UHF combiner will I minimize that interaction?
A combiner minimizes interaction, where they're connected.
A spacing on the same mast of at least 3-4', minimizes wave interaction between the two.

Heaviest antenna on the bottom.
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