what antenna is best for the lower channels 4 5 7 9 etc.?

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what antennas get the low uhf local channels best. outdoor antenna amplified antennas

Answer
Outdoor antennas always offer the potential for better reception than indoor or attic-mounted antennas. Three manufacturers of quality, high performance High Band (channels 7 through 13, 174 - 216 MHz) and Low Band (channels 2 through 4, 54 - 72 MHz and channels 5 through 6, 76 - 88 MHz) VHF antennas that foremost come to mind are Wade/Delhi, Winegard and Antennacraft. (For a more complete list of TV antenna manufacturers please use my DTV Antenna Resources Google Docs resource listed below.)

When shopping for a quality antenna for DTV reception you should try to choose an antenna that has a reasonably low VSWR spec, preferably no higher than 1.6:1 or so. Typically manufacturers of lower quality, lower performance antennas will often omit published VSWR specs for such antennas. Itâs also important to be aware that directional, narrow beamwidth antennas (or omnidirectional, CEA-909-compliant âSmart Antennasâ for shorter TX-to-RX distances,) can provide the best reception performance in an environment where strong multipath and adjacent-channel interference may be present. Just remember that the more directional the antenna the more important it becomes to accurately aim the antenna, often toward each TV stationâs transmitter if you have a good RF line-of-sight, whenever you want to view programming from that particular TV station. For outdoor antennas this often necessitatesâor is best performed byâthe use of an appropriate, high quality rotator if you have TV transmitters spread across your horizon.

One alternative to purchasing a turnkey off-air TV antenna is constructing the very popular, do-it-yourself high performance Gray-Hoverman antenna. (Please see the Digital Home Forum resources listed below if you would like more information.)

I highly encourage you to take the time to carefully and thoroughly read through the âOTA FAQ & Knowledge Baseâ of the Canadian Over-the-Air (OTA) Television Forums on the Digital Home Website; you will not find a better compendium of over-the-air TV reception and television antenna information anywhere. (Note: the information and resources apply in large part to everyone who relies upon an off-air antenna for television reception, but it will be the most helpful to those who reside within North America.)

Another excellent source of information on the subject of TV antennas is Ken Nistâs HDTV Primer Website. I highly recommend you read through the HDTV Primer resources to which Iâve provided links below.

I also recommend reading through the articles on DTV reception, esp. those under the section titled THE DIGITAL TV TRANSITION, as well as the antenna reviews on Peter Putmanâs HDTVexpert Website.

Ideally, if youâre able to use an outdoor antenna you should mount the antenna at least 20 feet (~ 6 meters) to 30 feet (~ 9 meters) above the ground or no less than 10 feet (~ 3 meters) above any nearby surrounding horizontal surfaces and/or structures.

If the terrestrial TV signals you receive at your site are too weak for your antenna, for example signals from distant TV transmitters, and you need or would like to amplify your RF signals, (providing that youâre not exposed to significant levels of RF interference and noise at your site,) I recommend using one of the following high performance mast-mounted units: either the CM-7777 Titan 2 preamplifier from Channel Master or one of the ultra low-noise HDTV preamplifiers from Research Communications in England. (Note: for U.S. residents the latter, even though superior to almost all other RF preamplifiers including Channel Masterâs CM-7777, will cost approximately US$150 shipped - or roughly three times the cost of the Channel Master unit.) Also, be very careful when choosing RF amplifiers for terrestrial TV applications; VHF antennas are much more susceptible to RF noise, which in turn can be easily exacerbated by amplification. In general itâs best to choose an appropriate (VHF) TV antenna with a sufficiently high passive gain rather than relying upon a lower-gain antenna and amplifier combo.

One last item: when it comes to the highest performance, high quality coaxial cable for your antenna downlead I highly recommend spending a little extra in order to use Beldenâs nonpareil RG-6/U or RG-11/U Tri-Shield coaxial cable. Please use my Google Docs resource titled âDTV Antenna Resourcesâ if you would like more information.


######################## RESOURCES ########################

Digital Home Forum
â OTA FAQ & Knowledge Base
http://www.digitalhome.ca/forum/showthread.php?t=41102&pp=30

HDTV Primer (an excellent source of information on antennas)
â Antenna Basics
http://www.hdtvprimer.com/ANTENNAS/basics.html
â Choosing an Antenna
http://www.hdtvprimer.com/ANTENNAS/choosing.html
â Common TV Antenna Types
http://www.hdtvprimer.com/ANTENNAS/types.html
â How Big Should the Antenna Be?
http://www.hdtvprimer.com/ANTENNAS/sizing.html
â Comparing Some Commercially Available Antennas
http://www.hdtvprimer.com/ANTENNAS/comparing.html
â Choosing a Mounting Site
http://www.hdtvprimer.com/ANTENNAS/siting.html
â It doesnât work! Now what?
http://www.hdtvprimer.com/ANTENNAS/fixes.html
â Erecting a TV Antenna (Main Page and Index)
http://www.hdtvprimer.com/ISSUES/erecting_antenna.html

A/V Science (AVS) Forum
â HDTV Technical
http://www.avsforum.com/avs-vb/forumdisplay.php?f=25
â The Official AVS Antenna Topic!
http://www.avsforum.com/avs-vb/showthread.php?t=381623&pp=60

DTV Antenna Resources
http://docs.google.com/View?id=dhpmqnbb_15f5t9j3gb
(Periodically updated and revised as needed)

________________________

âHey Kids, Time For A Game Of musical Chairs!â
http://www.hdtvexpert.com/pages_b/MusicalChairs.html

As Analog Shutdown Nears, Antenna Reality Emerges
http://www.printthis.clickability.com/pt/cpt?action=cpt&urlID=29040747&url=http://broadcastengineering.com/RF/analog-shutdown-nears-antenna-reality-emerges-0609/index.html&showBibliography=Y

About TV and FM Antennas
http://kyes.info/antenna/antennadex.html

TVTechnology
â Low-Band VHF DTV Revisited
http://www.tvtechnology.com/article/11506
â Antennas for DTV Reception
http://www.tvtechnology.com/article/11584
â Solving VHF DTV Reception Problems
http://www.tvtechnology.com/article/79862
â DTV Transition Survival Guide
http://www.tvtechnology.com/article/72376

Help with finding a good HDTV antenna?
http://answers.yahoo.com/question/index?qid=20090219121841AA75gR9
Is there any downside to mounting an antenna on a chimney�
http://answers.yahoo.com/question/index?qid=20081126104936AAmFvOr

[PDF] Thin Air: ATSC Reception Isnât Always Easy
http://www.edn.com/contents/images/6656302.pdf
Brian Dipertâs âThin-Air ATSC (And NTSC)â Articles
http://www.google.com/search?hl=en&num=100&aq=f&lr=lang_en&as_occt=title&q=site:edn.com+%22Thin-Air+ATSC+(And+NTSC)%22

________________________

[PDF] SBGH NAROD Antenna
http://www.wuala.com/300ohm/Documents/SBGH%20NAROD%20ANTENNA.PDF
MecEng Drawing Notes
http://www.digitalhome.ca/forum/showpost.php?p=926298
[ZIP] Double-Bay Gray-Hoverman High-VHF DBGH Antenna CAD Drawing
http://www.user.dccnet.com/jonleblanc/Canada_TV_Stations/Gray-Hoverman/DBGH_VHF_hi_Antenna_LT.zip

Gray-Hoverman Antennas
http://imageevent.com/holl_ands/grayhoverman

Digital Home Forum
â The Gray-Hoverman Antenna for UHF Television Reception
http://www.digitalhome.ca/ota/superantenna/
â Which Gray-Hoverman TV Antenna Should I Build?
http://www.digitalhome.ca/forum/showthread.php?t=81982&pp=15
â (Gray-Hoverman) GH with NARODs for VHF-HI & UHF
http://www.digitalhome.ca/forum/showthread.php?t=99907&pp=15
â Gray-Hoverman Fractal & VHF R&D
http://www.digitalhome.ca/forum/showthread.php?t=95684&pp=15
(Applying Fractal mathematics to antennas is helpful to reduce the size of VHF / High-Band VHF antennas such as the Gray-Hoverman designs with a minimal hit to gain.)
â Co-linear High-VHF DBGH Plans
http://www.digitalhome.ca/forum/album.php?albumid=133
http://www.digitalhome.ca/forum/showpost.php?p=891066

How to make a fractal antenna for HDTV / DTV plus more on the cheap
http://ruckman.net/blog/print.php?news.21
DTV / HDTV Fractal Antenna Showdown!
http://ruckman.net/blog/print.php?news.22
 

help with finding a good hdtv antenna?

mom2_3hell

i libve 35 miles from towers. Bought a phillips 50 db amplified antenna. It worked great during all tests tv station did. They shut down the analog signal went to all digital. Now I cant get channels to come in at all. Why? Tv station said i needed a better antenna even tho it was working fine. So any suggestions...tired of buying these that dont work,

Answer
There are basically two vitally important factors that govern your ability to effectively receive DTV signals: the quality and strength of the RF signal and the proper Transport Stream data, specifically the Program Map Table and the Program Association Table data, contained within the mandatory Program and System Information Protocol metadata that accompanies every ATSC-compliant DTV data stream. (If a TV station sends incorrect PAT and PMT data then you will be unable to watch and/or listen to that station. Your only recourse is to submit a formal complaint to that television station.)

In addition, co-channel interference and multi-path interference can also result in severe reception problems when dealing with digital television signals. The following is a quote from the Wikipedia entry on Digital Television: âMulti-path interference is a much more significant problem for DTV than for analog TV and affects reception, particularly when using simple antennas such as rabbit ears. This is perceived as âghostingâ in the analog domain, but this same problem manifests itself in a much more insidious way with DTV. (What was âghostingâ in analog becomes intersymbol interference (ISI), which causes data corruption, in digital TV. Beyond a certain point, corrupt data is as good as no data.) IEEE engineers recommend using an attic or outdoor antenna for DTV, if possible, rather than an indoor antenna, because reflections and other interactions of the signal with objects (including bodies) in the room will increase multipath interference. Unlike the problems of the preceding paragraph, multi-path can be worse for DTV under high signal conditions. It is perceived by the viewer as a spotty loss of audio or picture freezing and pixelation as people move about in the vicinity of the antenna and is often worse in wet weather due to increased reflection or re-polarization of the DTV signal arriving from multiple paths. In extreme cases the signal is lost completely. The cure is to employ a directional antenna outdoors, aligned with the transmitting location.â

In your case, with such broad reception difficulty, the primary culprit is most likely due to a poor quality RF signal at the RF/Antenna input on your HDTV. At a distance of 35 miles from the TV transmitters of your favorite local television stations it should be fairly straightforward to acquire sufficiently strong signals from those stations, however I would be extremely reluctant to recommend an indoor antenna especially if you reside in a single family dwelling. Itâs my opinion that the Philips SDV2510/27 antenna is simply ineffective and inadequate when it comes to DTV reception at your location. At best Philipsâ indoor antennas have a reputation of barely mustering middle-of-the-road performance.

The first step toward remedying the problem is to thoroughly analyze your specific location with respect to the broadcast television signals in your area. I recommend starting with the TV Signal Locator on the TV Fool Website along with antenna mapping and optimization information obtained from the CEA/NAB AntennaWeb Website. Once you know the direction and distance to each of the TV transmitters in your area you can begin narrowing the search for the optimum antenna. For service areas that fall into the âSuburbanâ area designation and beyond I strongly recommend a good quality outdoor antenna mounted to a rigid metal mast extending at least 20 feet above the adjacent ground and/or at least 10 feet above the top of the nearest structure, e.g., the roof line of your house. The following is quoted from a paper by O. Bendov titled On the Validity of the Longley-Rice (50,90/10) Propagation Model For HDTV Coverage and Interference Analysis: âThe FCC set the antenna height above ground at 30'. That elevation may have been appropriate during the 1950âs. Nowadays, the average height of outdoor antennas would be lower. For example, if the height of the receive antenna were 15' above ground, a received UHF signal would be -6.0 dB below that expected from an antenna 30' above ground. It would take quadrupling of the transmitter power to make up this loss.â

At the very least you should be using a directional antenna that is capable of receiving UHF and high-band VHF off-air television signals, and in some cases even low-band VHF if there are any TV stations in your area that are using frequencies within that range for digital broadcasts. The specific type of receiving antenna will depend on the direction, distance, and height above average terrain as well as the effective radiated power of the TV transmitters. It will also depend on the surrounding terrain elevation and âclutterâ between the transmitters and the receiving antenna as well as the performance of the DTV receiver/tuner. Your best choices will generally be either an outdoor 4-bay bowtie UHF antenna along with a good quality VHF antenna mounted to a single antenna mast or a heavy duty Yagi or log-periodic dual-band UHF/VHF antenna from a manufacturer such as Channel Master, Winegard, Wade/Delhi, AntennaCraft or Antennas Direct. (Please see my answer to the first Y!A question listed below for additional resources.)

If you are careful in selecting and installing your antenna you should not need to use a low-noise RF preamplifier. (In a noisy and/or multipath-prone RF environment a preamplifier can often exacerbate reception problems rather than help.) However if you find yourself in need of a high performance, low-noise RF preamplifier I highly recommend the mast-mounted Research Communications Type 9254 Wideband E-pHEMT Low Noise Preamplifier orâas a second choiceâthe Channel Master CM-7777 Preamplifier. (Note: the latter is about one-third the cost of the former with only a slight decrease in real-world performance.)

If you have TV transmitters spread over a moderately wide azimuth (and youâre using a highly directional antenna) then you will need to install a heavy duty antenna rotator, aka rotor, and a programmable controller. (For what itâs worth worm-drive antenna rotators offer superior performance and longevity but are generally far beyond the budget of the average consumer.)

So at the very least you will need to purchase a directional outdoor UHF/VHF antenna that has sufficient gain throughout the UHF DTV band, particularly at the higher end of the band. Along with that you will want to properly install a rigid, heavy duty antenna mast to support the antenna and any supplemental equipment that you may need. I highly recommend that you download and read Channel Masterâs excellent Off-Air Antenna Installation Guide, to which Iâve provided a link below. I also advise that you purchase the highest quality, low-loss 75Ω downlead constructed from Tri-Shield RG-6/U or RG-11/U coaxial cabling. (A good source is Blue Jeans Cable. They sell the excellent Belden 1694A RG-6/U coaxial cable, terminated with your choice of connectors*, in any length you may need. If you need a downlead longer than 50 feet or so I recommend that you consider the RG-11/U equivalent: Belden 7731A.) *(When installing coaxial cabling outdoors always be sure to use coaxial connectors rated for weather-tight outdoor use.)

Last but not least you should take steps to ensure that your earth ground and your electrical bonding and grounding is up to the latest electrical codes and is optimized for sensitive electronic equipment. Also, if your area is prone to lightning strikes you will also need to take the necessary precautions, which may include the installation of charge dissipation terminals and/or other lightning discharge devices along with the appropriate TVSS protection equipment.

######################## RESOURCES ########################

Which is the best digital antenna?
http://answers.yahoo.com/question/index?qid=20090209141100AAZSR5n
Is there any downside to mounting an antenna on a chimney �
http://answers.yahoo.com/question/index?qid=20081126104936AAmFvOr

TV Fool
http://www.tvfool.com

CEA/NAB Outdoor Antenna Optimization Information
http://www.antennaweb.org
AntennaWeb - Types of Antennas
http://www.antennaweb.org/aw/info.aspx?page=more_info
AntennaWeb - Frequently Asked Questions
http://www.antennaweb.org/aw/info.aspx?page=FAQ

TV Query and TV List Database
http://www.fcc.gov/fcc-bin/audio/tvq.html
Map Book of All Full-Power Digital Television Stations
http://www.fcc.gov/dtv/markets/welcome.html

HDTVexpert âThree For DTVâ
http://www.hdtvexpert.com/pages_c/ThreeFor.html
HDTVexpert âFive Antennasâ
http://www.hdtvexpert.com/pages_c/Five_Antennas.html

HDTV Antenna Reviews
http://www.hdtvantennalabs.com/hdtv-antenna-reviews.php

[PDF] Solving TV Reception Problems
http://rapidshare.com/files/201366511/TVRECEPE_-_Solving_TV_Reception_Problems.pdf

Canadian Over-the-Air (OTA) Television Forums
http://www.digitalhome.ca/forum/forumdisplay.php?f=81

AVS Forum: The Official AVS Antenna Topic!
http://www.avsforum.com/avs-vb/showthread.php?t=381623&pp=60
Antennas, rotators, boosters/preamps... for wide-band VHF/UHF
http://www.avsforum.com/avs-vb/showthread.php?t=546066&pp=60

[PDF] Channel Master Off-Air Antenna Installation Guide
http://www.pctinternational.com/channelmaster/0612/pdfs/guide_AntennaInstallation.pdf
http://www.pctinternational.com/channelmaster/0612/documentation.html

Research Communications High Performance E-pHEMT Low Noise Preamplifiers
http://www.researchcomms.com/hdtv.html

Channel Master CM-7777 MATV Mast-Mounted Titan 2 Preamplifier
http://www.channelmasterintl.com/amplifiers.html

[PDF] Belden Coaxial Cable Catalog
http://www.belden.com/pdfs/03Belden_Master_Catalog/06Coaxial_Cables/06Coaxial_Cables.pdf

Analog/Digital RF TV Cables at Blue Jeans Cable
http://www.bluejeanscable.com/store/rf/index.htm
 

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