Hillsboro, OR: Antenna woes - TIme for a roof mount? - AVS Forum
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post #1 of 17 Old 10-22-2012, 02:09 PM - Thread Starter
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According to the report I should -very- easily pull in local signals. However, the best I've been able to do is pull in most of the "green" signals on the primary azimuth heading and they have mixed signal strength. I have tried attenuators of various sizes before and after the distribution amp (thinking it may be -too- strong or that I might have multipath issues. The attenuators did nothing to improve the signal strength or quality. When the picture breaks up I have very low signal strength. I have tried using 4 different antennas at this point in 3 different locations:

Antennas:
1) Offbrand medium directional antenna. Doesn't seem to pull in anything; was hanging in the attic when I moved in.
2) DIY 4-bay bowtie (design referenced a few posts back). Results in slightly less signal strength than the very large directional antenna.
3) "Very large" Terk directional antenna (8ft long, maybe 6-7ft wide). It's a UHF/VHF/FM design and looks very similar to THIS.
4) Indoor loop + bunny ears antenna

Other equipment:
1) Channel master 1->8 distribution amp with 4dB gain. Unused outputs are terminated. From the distribution amp, there is ~ 30 ft or so of RG-6 to the TV/tuner.
2) Channel master 7778 preamp (makes maybe "1 bar" of signal strength difference... at best). Yes, it's plugged in and the power injector is wired correctly (incorrect wiring = no signal).

House location details:
House has 2 large attics and is covered in vinyl siding. There are 2 large, dense trees right between the LOS of the attics and towers (5-10ft from the exterior of the attics). Additionally, there is another house in the way, a large stand of pine trees, and a regional airport ~1/2 mile away (all between the towers). The house is in a slight depression but the attic would have a clean LOS to the towers if there were no trees or other homes in the way.

Locations & results:
1) Indoors in back attic; this is the furthest location from the distribution point. Approximately 15-20ft off the ground. The antenna is connected to 100ft of RG-59, into a wall connector (quality of terminations is unknown), and then through 75+ feet of RG-6 to my distribution amplifier. This has been the best location so far. Antennas 2&3 result in a watchable picture with occasional picture break-up on 43. 49 comes in very clearly but 46 and 47 don't come in at all (same azimuth!). Adding the pre-amp doesn't resolve the signal strength issues.
2) Indoors in front attic; ~75ft of RG-59 to distribution amp. Quality of terminations is unknown. This attic is a huge pain to navigate but has slightly less obstructions between the attic and towers. This is 1-2 bars lower in signal strength versus the back attic.
3) Front yard. Only the airport and pine trees are in the LOS here. 100ft of RG-59 to the distribution amp. About the same as the front attic in picture quality. This would not be an acceptable permanent location; I just did it as a test.
4) Inside very close to TV; ~8ft of RG-6 between the antenna and TV. Very poor signal strength.

Questions:
1) Is my next step an antenna mast on the roof (prob. use an eave mount)?
2) If so, what brands are recommended? Any installation how-tos or recommendations/tips?
3) Would mounting the large Terk cause any problems? Should I use the preamp? There will be at least 100ft of cable (good solid core RG-6) from the antenna to the distribution amp.

Thanks!

Note, here is my original post on the issue (same tower, different signal strengths despite TVFool ratings): http://www.avsforum.com/t/1352044/strange-reception-pattern-help
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post #2 of 17 Old 10-23-2012, 08:20 AM - Thread Starter
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Any thoughts? Thanks!
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post #3 of 17 Old 10-23-2012, 09:55 AM
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You need to start with the basics first, then go from there. At just 11 miles out, you should not need a dist amp or pre amp.

You need to find out what channels you can get with a short piece of RG6 right at the antenna.without the pre-amp or dist amp.
If you can manage to bring a small HDTV with a tuner into the attic, you can perform this test. Or at the very least, run a temp rg6 down to where you can put an HDTV as close as possible to the antenna.

Make sure the antenna is pointed in the right direction which in your case is East. Try using the Terk antenna, and make sure you are pointing the right end towards the transmitters ( if you look at the picture in the link you provided, the front of the antenna would be the end on the right, the long skinny end).

Do a re-scan on your tv and let us know what you find.
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post #4 of 17 Old 10-23-2012, 10:20 AM
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I agree with mikepier. With 25 stations located 11-12 miles away, your antenna should be fine in the attic, and you cannot use an amplifier at all, probably not even a distribution amp (you'll just cause overload). Just use one simple splitter at your distribution point and minimize the number and lengths of coax, connectors, etc. The large antenna you referenced is overkill for your area and it seems you have a high number of connectors and an awful lot of coax (some of it the non-preferred RG-59 kind). Perhaps one or more coax connectors are bad or not fitting properly. Best to get rid of the connectors on the wall plates, switch each to a wall plate with a small hole in the center and run your coax straight through. Every connection increases the possibility of signal loss. Your medium-sized directional antenna in your attic should work fine. Inspect the antenna for any phasing lines that are touching when they are supposed to be separated (that would short out the antenna), and check the connection points to make sure everything is sound. Of course, the antenna has to be aimed a bit south of due east. Try a reasonable length of RG-6 that you are sure works properly (like a new 50-foot length) and run it directly from your attic antenna down through your attic opening and directly to your tv as a test. If that doesn't yield good results, then either the antenna is somehow shorted out or the connection point is damaged, or maybe your tv has a problem of some kind.
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post #5 of 17 Old 10-23-2012, 10:35 AM - Thread Starter
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Quote:
Originally Posted by mikepier View Post

You need to start with the basics first, then go from there. At just 11 miles out, you should not need a dist amp or pre amp.
You need to find out what channels you can get with a short piece of RG6 right at the antenna.without the pre-amp or dist amp.
If you can manage to bring a small HDTV with a tuner into the attic, you can perform this test. Or at the very least, run a temp rg6 down to where you can put an HDTV as close as possible to the antenna.
Make sure the antenna is pointed in the right direction which in your case is East. Try using the Terk antenna, and make sure you are pointing the right end towards the transmitters ( if you look at the picture in the link you provided, the front of the antenna would be the end on the right, the long skinny end).
Do a re-scan on your tv and let us know what you find.
Mike, thanks for your help. Location #4 was 8ft from my TV with no splitters, amps, or anything else. I only got the 2 strongest stations and they were choppy when the antenna was in that position (tried the Bowtie and indoor antenna). However, this location is far from optimal because it is very low.

Yes, the antenna is pointed in the right direction. I do have a portable HDTV, I'll try that in the attic.

GCD: I agree with your coax assessment; I'm not comfortable with the very cheap RG-59 and number of connectors. I plan on running an unbroken RG-6 to the distribution amp but 1st I need to find a good antenna location. I have 3 ATSC tuners (Tivo, Samsung TV, and SiliconDust) and all three achieve similar results. The reason I'm going through all this pain is that the signal is just strong enough for the TV but not for the SiliconDust (due to the internal 2:1 splitter). I'd like to use my HTPC the way it was intended smile.gif.

Sidenote: All antennas have been using the same transformer... should I try a new one or is this something that typically doesn't fail?

I agree with everyone, I -should- be getting decent reception with minimal effort in my location. However, after many hours of experimenting that has not been the case.
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post #6 of 17 Old 10-23-2012, 05:05 PM
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Yes, I had forgotten to consider the transformer/balun. Try a different one if you can, since they can fail. Also, you should consider bypassing the distribution amp completely, since it might be bad, or simply overloading your system. At 11 miles out, a medium-gain antenna in any location (even laying on your living room floor) should be yielding strong signals throughout without any amplifier. Leave your attic antenna where it is (while inspecting it for a short or something broken) and otherwise diagnose for a likely connection/coax/balun problem.
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post #7 of 17 Old 10-24-2012, 08:03 AM
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I'd try the Terk combo antenna that you have, using a good-quality ("known-good", as they say) coax. No preamps or any of that stuff, yet.
Get an FM Trap from radio Shack, and a few attenuators (RS doesn't stock them right now, so try Lowe's or Home Depot, or some other places).

Try the antenna and cable with an FM Trap first, to see if it's just overload from nearby strong FM stations.
Then, try about 6 or 10 dB of attenuation, maybe even 20 (attenuators just screw together, and come in 3, 6, 10 and 20 dB values, and add together).
If things work better, use a 4-way or 8-way splitter (7 dB loss, and 10.5 dB loss, respectively) to feed your sets, adding attenuators to the antenna line (at the splitter) to make up the difference between what worked with attenuators only, and he splitter arrangement.

You're likely getting overloaded by too much signal, and also too much FM. The medium-sized antenna isn't bad, since it has a medium beamwidth, but there may still be too much signal.

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post #8 of 17 Old 10-24-2012, 11:26 AM - Thread Starter
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kenglish, I have a full set of attenuators (3->20db) and all they do is attenuate the signal (i.e. I don't think it's an overload issue). I will try the FM trap + a new Balun (suggested previously) and see if things improve.
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post #9 of 17 Old 10-27-2012, 05:38 AM
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Please put your location in the title of ALL antenna help threads as instructed in the stickys. See my edit.

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post #10 of 17 Old 11-15-2012, 10:44 AM - Thread Starter
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OK, I've done some more experimenting. I took my wife's portable DVD/HDTV into the attic and tried a variety of antenna, amplifier, and transformer options. The player is nice because it displays signal strength AND signal quality. I used a compass app on my cell phone to roughly aim the antenna and then tried a variety of angles (up/down & left/right).

- The best reception (~80% signal strength, similar signal quality level) was achieved when I used the large directional antenna + CM 7778 pre-amp. I've gotten a 10% improvement in signal strength using the pre-amp and this has allowed me to start using my SiliconDust tuner on most of the major channels.
- The small loop antenna barely pulled in anything (even with a pre-amp)
- The reception is just slightly worse at the end of the long coax running through the house... in other words I've eliminated the house wiring as an issue.
- I tried a new transformer and it didn't make any difference
- I carefully went over the large antenna looking for shorts and couldn't find any. I also intentionally shorted the phases and that killed the picture (so antenna is working / not damaged).
- I've tried a few ground level locations with the loop antenna and the reception was poor.

I'd really like to improve the reception further if possible. Any thoughts for my next steps?
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post #11 of 17 Old 11-15-2012, 03:37 PM
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Quote:
Originally Posted by Greg_R View Post

OK, I've done some more experimenting. I took my wife's portable DVD/HDTV into the attic and tried a variety of antenna, amplifier, and transformer options. The player is nice because it displays signal strength AND signal quality.

Why don't TV sets still show this? My friend got a new Sony HDTV that had no signal strength or quality displays at all. I had to take a laptop and an ATSC USB stick over to her house to get her antenna set up correctly. She lives in small depression on the side of a hill and the towers were directly behind her large fireplace so it wasn't trivial.

NOW: my post on AVS Forum.
NEXT: someone else's post on AVS Forum.
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post #12 of 17 Old 11-15-2012, 04:08 PM
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Quote:
Originally Posted by Greg_R View Post

OK, I've done some more experimenting. I took my wife's portable DVD/HDTV into the attic and tried a variety of antenna, amplifier, and transformer options. The player is nice because it displays signal strength AND signal quality. I used a compass app on my cell phone to roughly aim the antenna and then tried a variety of angles (up/down & left/right).
- The best reception (~80% signal strength, similar signal quality level) was achieved when I used the large directional antenna + CM 7778 pre-amp. I've gotten a 10% improvement in signal strength using the pre-amp and this has allowed me to start using my SiliconDust tuner on most of the major channels.
- The small loop antenna barely pulled in anything (even with a pre-amp)
- The reception is just slightly worse at the end of the long coax running through the house... in other words I've eliminated the house wiring as an issue.
- I tried a new transformer and it didn't make any difference
- I carefully went over the large antenna looking for shorts and couldn't find any. I also intentionally shorted the phases and that killed the picture (so antenna is working / not damaged).
- I've tried a few ground level locations with the loop antenna and the reception was poor.
I'd really like to improve the reception further if possible. Any thoughts for my next steps?

Based on your test results, the only logical conclusion I can make is your attic is blocking most of the signal. In order to confirm this theory, you would have to mount the antenna outside on the roof. Is there a way you can temporarily hook up the antenna on the roof? Or at least aim it outside a window?
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post #13 of 17 Old 11-16-2012, 08:40 AM
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Something must be wrong. At 12 miles, a large antenna should be giving signal strengths in the 90s across the board without an amplifier, even in a typical attic. And a 7778 amplifier would likely overload with 20+ stations at your distance from the towers. I think mikepier is probably right - something is blocking the signals, maybe metal materials in the construction of your house or in houses around yours. Are you in a neighborhood with metal roofs, aluminum siding that extends up the sides of your and/or others' attics, metal foil insulation of some kind, extensive attic ductwork or are the homes in your area made with all-metal wall studs or stucco walls with embedded chicken wire mesh? A good test would be to try your DIY 4-bay bowtie out on the back deck/patio with your portable tv and your short coax. If signals immediately jump (on UHF channels only for the bowtie-type antenna) to the 90s, then it's got to be building materials.
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post #14 of 17 Old 11-16-2012, 09:55 AM
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Quote:
Originally Posted by scowl View Post

Why don't TV sets still show this? My friend got a new Sony HDTV that had no signal strength or quality displays at all. I had to take a laptop and an ATSC USB stick over to her house to get her antenna set up correctly. She lives in small depression on the side of a hill and the towers were directly behind her large fireplace so it wasn't trivial.

My LG shows signal strength and quality.
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post #15 of 17 Old 11-16-2012, 07:55 PM
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Sometimes signal strength info is hidden under several layers of the onscreen menu. But Samsung and Panasonic still provide this signal info.
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post #16 of 17 Old 11-19-2012, 11:02 AM - Thread Starter
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Quote:
Originally Posted by mikepier View Post

Based on your test results, the only logical conclusion I can make is your attic is blocking most of the signal. In order to confirm this theory, you would have to mount the antenna outside on the roof. Is there a way you can temporarily hook up the antenna on the roof? Or at least aim it outside a window?
Thanks Mike. I have tried a small antenna on my front porch but didn't get great results (there are a lot of dense trees in the way). I will try the window below the attic with the portable antenna and see if the signal strength increases. There is a house < 50' away with unknown materials. My home is vinyl siding with Tyvek (not metallic).

Tonight we've had high winds & rain (-not- a thunderstorm) and the signal strength has been wildly oscillating. I'm wondering if this pinpoints the trees as the problem? I mentioned in my first post the very large and dense apple tree outside the antenna location.

If the window doesn't show improvement I think I'll try a nearby location in a field (very clear line of sight to the towers). That should level set my expected signal strength. If that is good then I'll try the roof. My roof has a steep pitch and the mounting location will require a 40' ladder (to the base of the antenna mount). I want to exhaust all possibilities before undertaking that project.
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post #17 of 17 Old 11-19-2012, 11:13 AM
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Quote:
the signal strength has been wildly oscillating. I'm wondering if this pinpoints the trees as the problem? I mentioned in my first post the very large and dense apple tree outside the antenna location.

I think you have identified the problem...

I've taken a spectrum analyzer to a viewer's home in south St Louis that was, except for trees, within VISUAL range of multiple local towers. Reception was impossible for several of the stations when the wind was blowing.

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