What are the basic rules for TV signal reception?
1. Outdoor is generally better. Outdoor antennas have a better view of the transmitting station, with no building-induced signal loss. They receive less interference from other household electronic/electrical appliances, and they are less likely to receive reflected ghost signals from the building structure.

2. Higher is better. The higher an antenna is, the more direct signal it can receive from the TV transmitter, while at the same time reducing the reception of interfering signals from other household electronic/electrical appliances and reflected ghost-causing signals from other nearby structures. The higher the better, but any antenna should be at least four feet above the structure to which it is mounted, and ideally above the roofline.

3. Closer is better. If a position above the roofline is not possible, the antenna should at least be on the side of your building facing the TV signal broadcast tower.

4. Bigger is better. The larger an antenna, the more signal it receives. This is especially important on channels 2-6, where the longer wavelength requires a larger antenna in order to be efficiently received. Larger antennas also become directional which reduces ghosting caused by reflected signals coming from the side and the rear of the receiving antenna.

Once the type of antenna you need is selected using this guide, careful attention must be paid to its installation. While not difficult to install, antennas are sensitive to installation details. For wood-frame buildings where the antenna will be situated on the roof’s peak, the antenna should be at least four feet above the peak. When installed above a flat metal roof, the antenna should be at least ten feet above the roof. For multidirectional antennas, allow for some mounting flexibility so that the antenna can be moved a few feet in each direction in order to obtain the best picture on all channels before a permanent mounting position is selected.

Do these antenna recommendations take terrain into account? I live in a mountainous area and reception can be difficult.
Yes, the algorithm used by this web site to recommend categories of antennas for your location uses terrain data from two sources, the USGS and NASA’s shuttle radar terrain mapping project. This is important because, unlike AM radio signals, TV signals are line-of-sight and don’t follow the curvature of the earth. This means that obstructions such as hills, trees and buildings between the transmitter and the receiving antenna can block the signal entirely or reflect the signal into the antenna twice (ghosting). For best results in areas impacted by terrain, be sure to use your complete street address including house number, as well as city, state and ZIP Code.

Why do you need my address information?
Antennaweb.org is different from many other applications in that it is household (street level) specific. This level of detail is very important in terms of the reception of over-the-air analog and digital television. Basically, Antennaweb.org looks up in the air and determines what signals are available at your house and builds your station list and antenna recommendations based on this prediction. Your address information is used to provide you with the most accurate antenna recommendation available.

I seem to get different results if I enter just my ZIP Code than if I enter my whole street address. Why?
If you enter only your ZIP Code, the spot at the center of your ZIP Code will be used as the location for your antenna recommendations and stations listing. If you enter your complete house number, street name, city, state and ZIP Code, an attempt is made to find a location match at your household (street level) location. If your address can be located at the street level, you are likely to get more accurate recommendations. If the location goes to the center of your ZIP Code (either because your street address couldn’t be found or because you only entered the ZIP Code), it can sometimes be quite a long ways away from your street location. This has more impact in less densely populated areas where ZIP Codes cover larger areas, and in areas of high terrain where small adjustments can make a difference as to whether you have a clear line of sight to the TV tower.

I don’t see KCRG (or any specific station) in my list of stations, what antenna do I need buy in order to get it?
If a station is not shown in your list, often it is absent for one the following reasons:

Your location is not in the predicted Grade B signal area of the station (most typical if you are hoping to receive a station that is in another city, for instance a user lives in Tacoma but was hoping to receive Portland stations).
The station is broadcasting digitally at a lower power than what was allocated by the FCC and therefore the signal isn’t predicted to reach your location.
You have entered only your ZIP Code and not your complete street address. (This will have more impact if you live in sparsely populated areas or areas of high terrain.)

Can you tell me how to install my PR-8800 antenna (or any other specific model)?
No, unfortunately, we are not able to provide assistance with installation of specific models of antennas. We do not have access to wiring diagrams, specifications or other installation information regarding specific antenna models. If you need assistance with installing an antenna, we recommend contacting your local retailer or installer.

Can I put an antenna in my attic?
Generally, antennas do not perform optimally in an attic. Even when an antenna will perform well outdoors, reception of TV signals in an attic can be made very difficult by interference from other electrical devices. The building’s construction can also hinder the entrance of the TV signal or cause reflection of the signal, which leads to ghosting. Depending on building construction, you can expect to lose at least 30% of the signal. In a house with aluminum siding, signal loss could be 100%. Outdoor installation is always best.

What is an amplified antenna and how do I know if I need one?
An amplified antenna can improve a TV set’s tuner performance, especially if the antenna is used indoors. Amplified antennas used in yellow color code areas should always be rated for use in these areas. This guarantees that the amplified antenna will not overload the signal. Building construction techniques can seriously reduce the amount of signal that reaches the interior of the building in a yellow color code area, making an amplifier a useful tool.

In dark green color code areas, amplified antennas are highly desirable in order to preserve as much of the received signal as possible, especially when distributing the signal to a VCR and a TV. Also, this can provide some useful compensation for signal loss caused by building construction and position in the building.

In outlying areas a large directional antenna should be used, but this requires amplifiers and rooftop mounting in the blue and violet color code areas.

What is ghosting?
Many structures can reflect TV signals much like they reflect light. This can lead to the TV receiver “seeing” more than one version of the TV signal. Ghosting results when a TV signal arrives at the receiver via more than one path. Low areas in a neighborhood are especially susceptible to ghosting.

If ghosting is caused by a single structure that creates one distinct ghost image, a medium or large multi-directional antenna may be useful with careful positioning to eliminate the reflected signal. However, the antenna may require different positioning for each channel.

Directional antennas are the most ghost-resistant antennas since they “see” in only one direction and have a tendency not to see the reflected ghost signal. The further away from structures the antenna is located the less likely a problem will occur. Many factors, however, such as the structure’s total surface area, the direction it faces, and neighborhood terrain, will influence how much effect the structure will have on TV reception.

Which structures cause ghosting?
Nearby buildings that are higher than the TV antenna or block the antenna’s view in the direction of the TV station’s transmitter such as:

Church steeples
Apartment/condominium buildings
School buildings
Water towers
Industrial buildings
Office buildings
Warehouses
Large communications/radio/TV towers
Athletic field lighting towers
High tension power lines and towers

Which structures do not cause ghosting?
Trees and foliage aren’t usually a problem, but in some cases foliage can absorb TV signals and reduce their strength. Therefore, the best antenna locations should avoid foliage in the direction of the TV transmitter. The following usually do not cause ghosting:

Other homes and wooden buildings that aren’t taller than antenna location
Streetlight or utility poles
Cellular or PCS poles consisting of a single pole no higher than treetops
Ham radio antennas
Other TV antennas

Are there some areas not suitable for TV antennas?
High-rise buildings can cause a severe ghosting environment. While most of these cases can be solved by suitable directional antenna selection, there are a few cases where an antenna may not provide workable reception.

White color code areas are also not suitable for TV antennas. These are generally in very rural areas where the signal is too weak. A professionally installed tall tower, satellite-delivered network stations or lifeline cable is recommended in these cases.

On occasion, some households may find that the recommended antenna type does not provide a suitable picture. This may be due to placement or installation of the antenna, obstacles local to a particular household which interfere with reception, or other issues. While most of these cases can be solved by a suitable directional antenna, there are a few cases where an antenna may not provide workable reception. Distant, outlying areas in very rural locations may not receive a strong enough signal to provide an adequate picture.

Do all TV antennas pick up all TV stations?
No, all TV antennas do not pick up all stations. There are several different types of antennas. Which type of antenna is right for you will depend on what signals are available in your area and which ones you want to receive. Antennaweb.org is designed to suggest categories of antennas that will receive the stations predicted for your location.

Can my condo or homeowner’s association prohibit me from installing an antenna?
As directed by Congress in Section 207 of the Telecommunications Act of 1996, the Federal Communications Commission adopted the Over-the-Air Reception Device Rule concerning governmental and nongovernmental restrictions on viewers’ ability to receive video programming signals from direct broadcast satellites (”DBS”), multichannel multipoint distribution (wireless cable) providers (”MMDS”), and television broadcast stations (”TVBS”).

The rule is cited as 47 C.F.R. Section 1.4000 and has been in effect since October 14, 1996. It prohibits restrictions that impair the installation, maintenance or use of antennas used to receive video programming. The rule applies to video antennas including direct-to-home satellite dishes that are less than one meter (39.37″) in diameter (or of any size in Alaska), TV antennas, and wireless cable antennas. The rule prohibits most restrictions that: (1) unreasonably delay or prevent installation, maintenance or use; (2) unreasonably increase the cost of installation, maintenance or use; or (3) preclude reception of an acceptable quality signal.

The rule applies to viewers who place video antennas on property that they own and that is within their exclusive use or control, including condominium owners and cooperative owners who have an area where they have exclusive use, such as balcony or patio, in which to install the antenna. The rule applies to townhomes and manufactured homes, as well as to single-family homes.

The rule allows local governments, community associations and landlords to enforce restrictions that do not impair, as well as restrictions needed for safety or historic preservation. In addition, the rule does not apply to common areas that are owned by a landlord, a community association, or jointly by condominium or cooperative owners. Therefore, restrictions on antennas installed in common areas are enforceable.

On November 20, 1998, the Commission amended the rule so that it will apply to rental property where the renter has exclusive use, such as a balcony or patio. The effective date of the amended rule is January 22, 1999.

What does it mean when there is a “-DT”, “-LP” or “-CA” after a call sign?
“-DT” stands for Digital Television. During the transition from analog to digital TV, stations will broadcast both an analog signal and a digital signal. The station’s call sign followed by “-DT” indicates that this is the digital signal for the station.

“-LP” stands for Low Power and “-CA” stands for Class A. According to the Federal Communications Commission (FCC) web site, the Low Power Television Service (LPTV) was established by the FCC to provide opportunities for television service for locally-created and community-oriented programming. An LPTV station is limited to broadcasting at an effective radiated power of only 3 kilowatts for VHF channels and 150 kilowatts for UHF channels. LPTV stations MUST NOT cause interference to the reception of existing or future full-service television stations and must accept interference generated by such full-service stations.

Class A stations are a particular type of low power station. Class A licensees will have “primary” status as television broadcasters, thereby gaining a measure of interference protection from full-service television stations, even as those stations convert to a digital format.

Do I need to rescan?
You should scan your converter box or TV set for channels when installing equipment for the first time, after repositioning or moving an antenna around and again after June 12, 2009. While some boxes do this automatically, you may need to select “scan” manually.

Using the remote control for your converter box or digital TV select “menu” or “setup” or some similar term. Now select “scan,” “channel scan,” “auto scan,” or “auto program.”

From there, select “OK,” “auto scan,” or “channel scan” and wait while your converter box or digital TV searches for all the channels available to you in your area.

As some DTV stations will change their coverage after June 12, 2009, and new DTV stations will begin operating over time; you should periodically rescan to continue to receive old ones or to receive new ones (if your converter box or DTV does not automatically do this for you).

Once complete, you should be able to select the channels you want using the proper remote. For TVs connected to a converter box, the remote control for the converter box (not the TV) should be used to change channels.

Please be advised that these are generalized instructions only and that you should consult your owner’s manual for more detailed instructions on how to run a channel scan.

Why doesn’t my HD receiver work with my antenna?
Unfortunately, we are also unable to assist with specific installation or troubleshooting questions regarding HD receivers. Again, we recommend contacting the manufacturer or the retailer from whom you purchased the receiver.

What does the * (asterisk) in the DTV column stand for?
The asterisk in the Digital column indicates that the station is broadcasting a digital TV signal. Digital Television (DTV) is a new broadcasting technology that will transform your television viewing experience. DTV enables broadcasters to offer television with movie-quality picture and sound. It can also offer multiple programming choices and interactive capabilities. In order to receive and watch the digital programming you must have an integrated digital TV or a digital TV and a digital set top box. If the station is already broadcasting in digital, the Live Date column will be blank. If the station is not broadcasting digitally yet, a date when the station is projected to go live is shown in the Live Date column.

When I use Antennaweb.org to determine which affiliates are broadcasting a digital signal in addition to the analog signal, I see dates that are in the future. Why?
While there are TV stations serving all markets in the United States airing digital television programming today, not all stations are available in every market yet. Most stations will continue to provide analog programming through June 12, 2009. At that point, full-power TV stations will cease broadcasting on their current analog channels, and the spectrum they use for analog broadcasting will be reclaimed and put to other uses. It may also be the case that your local stations are not yet broadcasting at full power for their digital signal. That might also explain why a station isn’t predicted to be received at your location.

What does the “Live Date” column indicate, and what does it mean when it says “TBD”?
The “Live Date” column indicates when a TV station is supposed to start broadcasting a digital signal. If the station is live already, the column will be blank. TBD indicates that the date the station is supposed to start broadcasting has not been established yet.

What is the difference between Digital Television (DTV) and High Definition Television (HDTV)?
DTV is the umbrella term used to describe the digital television system adopted by the FCC in December 1996. HDTV is a type of DTV service. HDTV provides high resolution programming in a widescreen format. A current analog TV picture can provide resolution of up to 480 horizontal lines. An HDTV picture can provide resolution of up to 1080 lines, providing improved picture detail. Aspect ratio is a comparison of screen width to screen height. Analog TV has an aspect ratio of 4 by 3, which means the screen is 4 inches wide for every 3 inches high. Widescreen HDTV format has an aspect ratio of 16 by 9. HDTV programs include Dolby digital surround sound, similar to the sound used in movie theaters and on DVDs.

What is multicasting?
When a station is not broadcasting in HDTV, it can provide multiple Standard DTV channels in digital, a process called multicasting. This means that a station can transmit multiple channels in the same bandwidth instead of just one.

Why is it that for some digital channels I need to tune to a UHF channel number such as 36, but for others I have to put in a number such as “4-1″?
The phenomenon you’re observing is related to PSIP channel mapping. PSIP stands for Program and System Information Protocol (PSIP) channel information. PSIP is data that is transmitted along with a station’s DTV signal that tells DTV receivers important information about the station and what is being broadcast (what channel to tune to for reception of the station, helps maintain current (analog) channel number branding, tells the receiver whether multiple programs are being broadcast, etc.).

Are all digital stations on UHF channels, and do I need a UHF-only antenna to receive them? What are the VHF and UHF bands anyway, and what do VHF and UHF stand for?
The Very High Frequency (VHF) band is the segment of the television broadcast band covering channels 2 through 13. The Ultra High Frequency (UHF) band is the segment of the television broadcast band covering channels 14 through 83. Currently, the vast majority of TV stations broadcasting in digital are using UHF (14 and up) channels to do so. This is not due to any technical requirement of digital broadcasting, however. It is mostly because the UHF channels were more likely to be available in most markets. Eventually, after the digital transition is complete and TV stations no longer need to broadcast in analog, they may switch and use their current analog VHF channels for digital instead. Antennas that receive UHF stations only and ones that receive both VHF and UHF are available. If you are fairly certain you won’t want to get any lower channels in the VHF 2-13 range, you could purchase one that is UHF only.

Can you provide station listings and antenna recommendations for locations in Canada?
Not at this time. AntennaWeb.org currently only provides information for U.S. addresses and broadcast stations.