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Old 15-Jun-2011, 4:27 PM   #1
egatx
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Antenna Suggestions for Leander, TX

Hello TV Fool Community,

I'd appreciate any help with an antenna configuration for my home. My report is here:

http://www.tvfool.com/?option=com_wr...001b43ccdd3e93

My goal is to receive the following (broadcast out of Austin, TX): NBC, ABC, PBS, CBS, CW, and FOX. I don't care about the longer-range stuff.

I recently moved into a new-construction, single-story home. My new home is less than a mile from my previous home. In my previous location, I could receive all of the above stations using a Terk HDTVa indoor antenna. In my new home, I can marginally receive all stations except CW and FOX using the Terk.

Admittedly, all of my reception experiments took place in the room in my home furthest from the tower; in other words, I was using the antenna in an area that maximized distance through my home to the signal origin. I assume this also maximized the potential for interference. This room is my "study", so there is a computer, TV, router, etc. nearby. This was mostly due to the fact that I don't have a great location for an indoor antenna anywhere else in my home (due to wife approval, etc.)

I'm using a SiliconDust HD Homerun as a tuner, using the Homerun software to measure signal strength.

Since it doesn't appear that an indoor antenna will work in my new location, I'd love to hear suggestions for a better solution. I am open to an outdoor antenna, though I would prefer something small if possible. An attic-mounted solution is also an option. I'm also curious if this indoor solution might be feasible if I can somehow find a better location in my home.

Any thoughts?

Thanks!
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Old 15-Jun-2011, 4:57 PM   #2
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Reception of your 'must-have' list is not too difficult.

If you want to try in your attic, an Antennacraft HBU-33 comes to mind. If your attic turns out to be a poor location due to reflections or signal attenuation, the HBU-33 can be folded back down and reinstalled outside.

You should have enough signal to split 4-ways with no amplifier needed.
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Old 15-Jun-2011, 5:59 PM   #3
egatx
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Awesome, thanks for the suggestion.

Regarding attic-mounted antennas: any thoughts on how much radiant barrier decking materials like Tech Shield (http://www.lpcorp.com/techshield/) affect reception? A quick google turned up some discussion but nothing definitive. The product documentations states that it "may cause interference."

My home has Tech Shield, and while I'd prefer an attic antenna, I don't want to waste time if I should just put one outside.

Thanks!
EG
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Old 15-Jun-2011, 6:05 PM   #4
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The aluminum in the TechShield product will form a nearly solid barrier to the desired signals.

A premium solution would be a Winegard HD7694P on the roof. Smaller antennas such as the RCA ANT-751 would have no problem receiving plenty of signal, enough to easily drive at least two receivers.
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Old 16-Jun-2011, 12:05 PM   #5
egatx
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Thanks for the info on the TechShield. I will plan on putting an antenna outdoors. Any reason I shouldn't attach it to my existing coax network?

And thanks again for the help. This is an awesome resource!

EG
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Old 16-Jun-2011, 5:23 PM   #6
GroundUrMast
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If the existing coax was installed by the cable company but has been disconnected, you should be able to use it with no problems, just be sure the 'drop' (the feed cable from the cable co. network) is disconnected from the grounding block or first splitter.

Active cable signal and an OTA antenna must not be mixed together, the result will be 'harmful interference' to aircraft, fire and police frequencies.

The cable from a satellite system can be reused. Diplexers and multiswitches will need to be removed though.
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Old 24-Jun-2011, 1:57 PM   #7
egatx
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Thanks to GroundUrMast for the help so far. I did finally have an antenna installed, and while it seems to be working reasonably well, I do have some questions and potential issues. Read on for details.

Earlier this week I hired someone to install an antenna for me. While it seems like a straightforward project, I didn't trust myself to ground and mount it properly; plus, it was relatively inexpensive to just pay someone for a turnkey solution.

Anyway, the installer used a CM 4220. Initially I was concerned that I wouldn't pick up a VHF-hi station (FOX), but he assured me that my proximity to the towers wouldn't be an issue. I decided to try it with the assurance that if it didn't work well, we could try something else with no obligation to purchase.

The antenna is mounted to my single-story roof, connected to my existing coax network (to a single run with no splitters), ending at a SiliconDust HD Homerun 2-tuner device.

In general, reception when actually viewing content seems decent; after several minutes of viewing, I observed no pixelation or drop-outs on any of the channels I care about.

However, when I viewed the signal quality/strength (via the HD Homerun software), I was surprised to see that the highest-numbered UHF channels showed overall weaker signal quality compared to the lower-numbered UHF channels and VHF-hi channel. Specifically, channels 43 and 49 (CW and CBS) showed signal quality hovering around 60%, whereas the lower-numbered channels were consistently in the high 80s and 90s.

Any opinions on whether or not this is a concern? Is this considered a marginal signal, and should I expect reception issues at some point? Any hints as to why some UHF stations appear weaker than others, and if so, any tips as to what I can do to rectify the issue?

Thanks for any help,
EG
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Old 24-Jun-2011, 4:09 PM   #8
egatx
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Potentially answering my own question: I now see on the TVFool analysis that the signals I'm having "trouble" receiving have relatively weaker signal strength. Surprisingly (at least to me), though, the weakest (FOX), on VHF, is just fine in terms of the measured signal strength.

Should I be concerned about reception on these stations?

Thanks,
EG
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Old 24-Jun-2011, 6:15 PM   #9
GroundUrMast
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I own HDHR's as well. I have noticed that the Signal Quality figure is the most important of the three numbers offered by the HDHomeRun Config Utility. If you see a stable Quality @ 75% or above, I doubt you will have any difficulty.

For example, I have a station 70 miles north showing mid 70's for strength, but 100% quality... Clean and stable beats 'just strong'.

Quality of 60% and under is close to the threshold of visible signal impairments in my experience with the HDHR.

Higher frequencies will be attenuated by long coax runs more than lower frequencies.

I still think a Yagi style antenna designed for channel 7 to 51 or 69 would provide the best reception for you.
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Last edited by GroundUrMast; 24-Jun-2011 at 6:20 PM.
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Old 24-Jun-2011, 6:54 PM   #10
egatx
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Thanks again for the guidance.

My HDHR "Signal Quality" does fluctuate in the "yellow" range (in the 60s, generally), though the "Symbol Quality" seems consistent at 100%.

I'd estimate my cable length at ~100 feet (~50 feet from antenna to network box, ~50 feet from network box to wall outlet).

I did place the antenna to try to minimize cable length, also attempting to hide it from street view. The resulting location has the antenna mounted on the edge of my roof line (i.e. the lowest point of the roof relative to the peak, near the gutters), pointed back towards the upward pitch of the roof. The roof slopes ~30 degrees and is probably 1.5-3 feet above the top of the antenna at the highest point. Is it possible that the roof itself is blocking the broadcast signal? I am assuming no, but never hurts to check.

I suppose I can try it and see if I have issues, and switch to another antenna if necessary.

Just curious: Why does the Yagi style antenna perform better than the bowtie style of the CM 4220?

Thanks again!
EG
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Old 24-Jun-2011, 7:41 PM   #11
Dave Loudin
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Yes, the roof IS partially blocking your signals. With the TVFool report you posted (assumes 10 ft. mounting height), you should have really strong reception of all the channels you are interested in. Before you start swapping out antennas, you should mount at a location as free of local obstacles as possible. The few dB you might lose in cable loss will be more than balanced out by the up to 20 dB increase in received signal.

As far as yagi vs bow-tie, it depends! A lot of bow-tie designs use small elements that don't perform as well at the low end of UHF. The sweet spot seems to be 9" or so whiskers. Of course, a too-small yagi would suffer the same fate. Also, the VHF/UHF yagis are specifically designed to be sensitive to VHF. Most bow-tie arrays are not, with the one design I am familiar with being a do-it-yourself project.
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Old 24-Jun-2011, 8:05 PM   #12
egatx
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Hmmm, that's disappointing that I placed the antenna poorly. I assumed that the location wouldn't make much of a difference given that the broadcast signals are strong; I thought it was enough just to get the thing outside and on my roof (which is about 12 feet off the ground, currently, but still a couple of feet below the peak, as I previously pointed out).

I live in a hilly area, and my home is located at a lower elevation that some close-proximity neighboring homes between me and the tower. No matter where I place the antenna on my roof, it will point at trees and other homes. Will these also present significant obstacles?

Before I settled on an outdoor antenna, I experimented by placing my Terk indoor antenna outside on my covered patio, running a cable directly into my HDHR as a quick test. In this configuration (with the antenna ~ 2 feet off the ground and seemingly blocked by the roof over the patio), I picked up everything except the VHF-hi station (7) just fine. Perhaps the style of antenna does matter in my case? I did this initial test with a Terk HDTVi.

According to the TV Fool report, the channels giving me trouble are ~2-3dBm lower than those I'm receiving without issue. Am I really on the hairy edge in my current configuration? Even the lower-powered VHF-hi station (7) comes in strongly; it seems like antenna location would affect it also.

In short: why do some stations come in strongly but not others? I'm hesitant to move the antenna until I have a reasonable understanding of why this matters. Reducing obstructions makes perfect sense, but I'm confused that anything is working well if my antenna is placed poorly.

Thanks,
EG
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Old 24-Jun-2011, 11:35 PM   #13
Dave Loudin
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Hmm. I could tell you live in a hilly environment by clicking on one of the stations in your report. Doing so pops open a depiction of the terrain profile used for the signal prediction. What a prediction can't account for are the houses and trees nearby. Ken Nist's site has an excellent primer on siting antennas. Note that the scattering/blocking caused by trees and houses affects UHF more than VHF.

Siting your antenna to look through the roof is not doing you any favors. When the shingles get wet, they will retain moisture for a while and block/scatter more signal. If reception stays stable through/after some rain, then you will probably be just OK.

I would encourage you to review the site I pointed you to with your installer to see what alternate mounting location might work better. It could be just a matter of moving along the gutter a few feet in one direction or another or raising the antenna in small increments that gets you in a better spot. Good luck!
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Old 25-Jun-2011, 6:12 AM   #14
John Candle
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Tv Antennas and Reception

If the antenna is pointed through the roof , then yes the roof is interfering with the reception.
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Old 26-Jun-2011, 2:56 PM   #15
egatx
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Thanks everyone for the suggestion to move the antenna. I am going to bring the installer back to move it a few feet to give it a more clean line of sight towards the horizon.

One other interesting thing I noted was that I can receive Univision (ch 13) perfectly (100% strength and quality) with the antenna in its current location. I guess this is because that tower is located somewhere else, and my current position isn't blocked by the roof for it.

Thanks again for the help,
EG
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Old 30-Jun-2011, 4:55 PM   #16
egatx
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Just to close this out... I moved the antenna a few feet so that it wasn't point through the roof, and now I'm getting >95% signal strength on all channels. The installer was surprised that this made such a difference (he said he's done dozens and never seen an issue). I suppose the presence of radiant barrier (which is all over my house, including the roof) attenuated the signal more than what might be "normal."

Thanks again to everyone here for your guidance.

EG
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