TiVo Community Forums Archives - Omni vs. Directional HD OTA antenna?

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Omni vs. Directional HD OTA antenna?
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Posted by: garberfc

I'm just finishing off my basement that will house the new theater. I'm planning on getting the DTV HD w/ TiVo as soon as it's available. I'm planning on supplementing the DTV signal with OTA local digital. I'm wondering about the antenna.

I've seen several sites that tell me what signal strengths to expect and even recommend antenna types and even specific models.
http://www.antennaweb.org/aw/Address.aspx
http://www.titantv.com/ttv/antennas...astType=digital

My question is, is there a problem with erring on the side of too much antenna? What I mean is, if these sites recommend a small omni-directional, and I decide to use a large omni or a medium directional or even opt for a signal amplifier, will I be hurting the potential signal?

Another question, if I need a directional antenna, does that cripple the TiVo's recording ability of the OTA signal? I can't imagine my running around repositioning the antenna as the TiVo swithes stations:rolleyes:

F

Posted by: rlj5242

quote:
I decide to use a large omni or a medium directional or even opt for a signal amplifier, will I be hurting the potential signal?

You could be. If you have large buildings, trees, etc. around your house, the signal will bounce off of them as well as going directly to your antenna. Both signals will be picked up but the bounced one will be slightly delayed. On an analog signal, this will appear as ghosting. With a digital signal, you will get a good signal strength but no picture.

quote:
if I need a directional antenna, does that cripple the TiVo's recording ability of the OTA signal?

Even though those sites recommend an omni-directional, most people get better results with a directional antenna. Check the Local HDTV section over at AVS to see what people in your town are using.

quote:
I can't imagine my running around repositioning the antenna as the TiVo swithes stations

Hopefully, your towers are grouped in a similar location. Directional antennas have a field of view, so if the towers are close to each other there is no need to re-position the antenna. This is why there is no plug-and-play with HD. Everyone has a different situation.

-Robert

Posted by: Knative

You can have too much of a good thing. I'm ~15 miles from one group of transmitters and was getting decent results with a small indoor Zenith Silver Sensor. The problem was I'd have to tweak the direction for certain stations and had to spin it 180 degrees to receive another that was ~25 miles away. When I got my Zenith HD-PVR I needed to eliminate the manual tweaking so I bought a directional outdoor antenna. Now I was getting less stations than before. Since the Zenith HD-PVR came with a 10db attenuator I figured I'd give it a try. Now I have a strong signal on all stations. Except for that one station who's transmitting from 180 degrees away from the others. I could get a decent signal off the back side of my outdoor directional antenna, but not solid enough to be able to trust a recording to. So I just added another smaller directional antenna to the mast pointing the other way and combined the signals into a single lead into the house.

So, if your transmitters are grouped together (which antennaweb will tell you) I'd go with a directional antenna. You can always throttle it back later with an attenuator. If they're spread out but are all close enough to get with an omnidirectional then it's an easy choice. If they're spread out and too far away for the omni you'll need multiple directionals combined together. That's where it gets interesting. The Local HDTV Info and Reception area at AVS would be your best source of this specific info.

Posted by: llogan

I'd only use an omnidirectional if you're relatively close to the broadcasting location. Directional antennas are much more preferable to me and I've had much greater success in implementing them. I try only to use omnidirectional antennas when the homeowner is close enough and aesthetics are an 'extreme' concern based upon neighbor feedback etc. Many people think the bay antennas, corner angle, Yagis, etc. are eyesores. Not me personally cause it's a means to an end :)

Posted by: garberfc

I'm not too worried about the look either (fortunately my wife doesn't visit this site ;) ).

Here's some of the stats from the www.antennaweb.com site based on where I live:

code:
Antenna         Station / City            Deg  Miles  CHN
yellow - uhf  WFSB-DT  CBS  Hartford       78°   8.8   33
yellow - uhf  WEDH-DT  PBS  Hartford      115°   6.6   32
yellow - uhf  WVIT-DT  NBC  New Britain   115°   6.6   30
yellow - vhf  WTXX-DT  WB   WATERBURY     114°   6.6   12
yellow - uhf  WUVN-DT  SAH  HARTFORD       79°   9.0   46
lt green-uhf  WHPX-DT  PAX  New London    132°  44.5   34
red - uhf     WTIC-DT  FOX  Hartford      113°   6.6   31
blue - vhf    WTNH-DT  ABC  New Haven     193°  20.5   10

I'd only be interested in the major networks and with the exception of ABC they are in the range of 78°-115° and all under 9 miles. We live on the side of a mountain (only 635ft) and when we look out the windows of our home we have a direct line of sight to the antenna(s) that are 6.6 miles away.

I wonder if CBS at 8.8 miles and a few degrees off would cause me to have to move a directional antenna?

The only other signal I'd be interested in is ABC at 20.5 miles and 193°!. I'd don't watch their local programming so would there be any reason or advantage to use the OTA instead of DTV?

The following is a link to the map produced my antenna web. The channel numbers from above are noted on the map.
www.prosoftds.com/antennawebmap.jpg

I'd enjoy hearing folks opinions as I'm trying to figure out the best configuration.

Thanks,

Frank

Posted by: JohnTivo

quote:

Originally posted by garberfc
I'm not too worried about the look either (fortunately my wife doesn't visit this site ;) ).

Here's some of the stats from the www.antennaweb.com site based on where I live:

code:
Antenna Station / City Deg Miles CHN yellow - uhf WFSB-DT CBS Hartford 78? 8.8 33 yellow - uhf WEDH-DT PBS Hartford 115? 6.6 32 yellow - uhf WVIT-DT NBC New Britain 115? 6.6 30 yellow - vhf WTXX-DT WB WATERBURY 114? 6.6 12 yellow - uhf WUVN-DT SAH HARTFORD 79? 9.0 46 lt green-uhf WHPX-DT PAX New London 132? 44.5 34 red - uhf WTIC-DT FOX Hartford 113? 6.6 31 blue - vhf WTNH-DT ABC New Haven 193? 20.5 10

Thanks,

Frank

garberfc,

You have the unfortunate situation that requires you to have an antenna that pulls UHF and VHF digital signals. Your local WB and ABC stations are using VHF... typically UHF is used to transmit DTV. Basically, you will need to make sure you have an antenna that gets both VHF and UHF.

Your proximity to the majority of the transmitters may require you to also use an antenna rotator to pull certain signals in IF you opt for a direction antenna.

Because you have signals coming from multiple directions, an omni-directional antenna maybe the best option to try out first. As many of us have found out, it can take some trial and error before you find the best setup for your location.

Posted by: Darin

I have a VERY similar situation. I ended up with two antennas, one for VHF, and one for UHF. The VHF is actually a VHF/UHF combo, as the VHF antenna that appeared to be the best for my situation had a UHF section, but I'm joining the two antennas with a VHF/UHF joiner, so the UHF that the combo picks up ends up getting filtered out. If you can't get them with an omni (and you'll probably be lucky if you can), then multiple antennas may be your only alternative. A rotor is problematic with a TiVo, since it can't turn the rotor for you, and you'd give up the advantage of dual tuners in certain situations.

Posted by: garberfc

quote:
Originally posted by Darin
I have a VERY similar situation. I ended up with two antennas, one for VHF, and one for UHF.

I think I'll just stick with the UHF antenna. We don't watch anything on the WB or any of the local programming on ABC. One potential problem, I understand some of the UHF stations will be moving to VHF after they have fully converted.

As far as a redundant signal for ABC goes; how often can I expect DTV to fall out?

Thanks,

Frank

Posted by: Darin

quote:
Originally posted by garberfc
As far as a redundant signal for ABC goes; how often can I expect DTV to fall out?

By that, do you mean how often do you lose your digital OTA signal? If so, I don't know that I ever do, but I don't watch that much network programming, and I get a 93-100 signal on all my channels.

Posted by: garberfc

quote:
Originally posted by Darin
By that, do you mean how often do you lose your digital OTA signal? If so, I don't know that I ever do, but I don't watch that much network programming, and I get a 93-100 signal on all my channels.

No, how often does the DirecTV signal get lost? How reliable is it? I live in the NE US.

Frank

Posted by: Darin

Oh! Now that Digital TeleVision is out, I never know if someone is talking about that, or DirecTV. :D

That varies by region, but typically it's a fraction of a percent of the time per year. You normally only experience it for a few minutes during a severe storm. Snow build-up on the dish can cause it too, but that can be fixed with heaters or covers. It can be frustrating when it happens, but the reality is it's a very small percentage of your viewing time. It's the worst in the SE. There's a document online somewhere that is in an old post here somewhere... I'll try to find it. It details actual calculatations of down time depending on where you are. But it's out of date anyway, as it's affected by satellite power and error correction levels, both of which have changed to some extent since it was published.

EDIT: Well shoot. It appears to be gone. The document I was referring to used to be at http://www.sonoradesign.com/pdfs/dbstutorial.pdf