Using A TV Antenna: The Basics

Snapshot:

• OVER-THE-AIR DIGITAL TV reception with an ANTENNA provides studio quality pictures and sound, including HDTV.

• DIGITAL TV channels use the same antennas as traditional analog channels.  If you have been using a TV antenna, try it for DIGITAL TV.
  

• There are two kinds of TV antennas: VHF band and UHF band.  Nearly all TV markets have TV stations that use the UHF band, so everyone needs an antenna that gets UHF.  Some markets also have TV stations with their digital signals in the VHF band; viewers in those markets need "combination" VHF/UHF antennas. 
  

• Indoor antennas may work if you're close to the TV transmitters, but outdoor antennas are better.

• Digital TV signals received with an antenna keep their quality for longer distances than traditional TV, but at the edge of their range, they  dissolve abruptly.   This is called the "cliff effect," where the signal just "falls off the cliff."
  

• Digital antenna reception requires experimentation.  Many factors affect how you well you will receive all your local digital TV stations with a single antenna.
  

• In cities where the TV stations have already converted to "all-digital," the biggest challenge for viewers has been getting their antennas to pick up all of the local digital stations. 
  

• A one-time investment in a quality antenna can provide years of free local TV.

Thanks to digital television, TV ANTENNAS are back.  Local television started as a broadcast service only, and early TV owners were experts in the use of TV antennas.  Antenna reception has always had uneven results, and OVER-THE-AIR viewers have sometimes had to deal with snowy pictures and "ghost" images on their local channels.  As TV viewers began connecting to CABLE  TV and SATELLITE TV, the "RABBIT EARS" antennas on top of many TVs disappeared. 

Over-the-air digital channels have excellent quality.  A digital TV program sent by a station's transmitter is received in exactly the same quality by a digital TV.  Once viewers have set up antennas to receive their local digital channels, they will get the best quality pictures and sound, including HDTV, that they could get from any other provider of local signals. 

Plus, over-the-air viewers can receive the new, "MULTICAST" programs that some TV stations are offering.  So, for viewers who are satisfied with the television choices available from their local TV stations, a one-time investment in a good antenna can provide years of free, crystal clear TV reception.

This site provides general information on how to plan for using a TV antenna to watch local digital channels, with helpful links.

Digital TV broadcasting uses the same channels as traditional analog TV, and the antennas don't care if a TV signal is analog or digital - it's still a radio signal.  And the type of program inside the TV signal - such as an HD program - also makes no difference to an antenna.  So antenna technology does not change for digital TV.  Current antennas that work well for analog channels should work well for digital channels.

TV signals were assigned channel numbers when TV began broadcasting, and these channels are still used today. There are two groups of channels, and the major difference between the groups is the size of the antenna needed to receive them.  The groups are:

• the "VHF" channels (channels 2 through 13).  These use larger antennas.  An indoor VHF antenna can be 2 to 9 feet wide.

• the "UHF" channels (channels 14 through 69).  These use smaller antennas.  An indoor UHF antenna is usually a circle of wire about 8 inches wide, or a "bow tie" about one foot wide.

There is one difference in the use of TV channels resulting from the digital TV transition.  Most TV stations that had their traditional analog channel in the VHF group (channels 2 -13) now have their digital channel in the UHF group (channels 14 - 51).  In some cities, this includes most or all of the major network affiliates.  (A few stations temporarily used UHF channels for digital, and they have moved their digital signals back to their VHF channels. In some cities, these digital signals on the VHF band have not had enough power to give the same reception as analog TV.)

What this means is that most viewers will have some local TV stations broadcasting in digital on both VHF and UHF channels.  So most people should use combination antennas that can receive "VHF/UHF" channels.  (A bonus for some of these antennas is that they also work for FM radio and FM "HD" channels.  You can "split" the antenna signal between your TV and your FM receiver.)  

What Makes A TV Antenna Work Best?   How well a TV antenna works is a combination of two factors: physics and magic. The physics factors are easy to predict, and you can use them to improve your antenna situation.  But many of the factors that affect a TV antenna can't be seen or planned for.  A good antenna can work badly and a bad antenna can work well.  Thus, the way to get a good result is to make a reasonable plan, then experiment. 

On the TV station side, factors that affect TV signal reception are the height of the transmitter antenna (higher is better) and the signal power (more is better).  (Some stations won't use their full digital channel power until after the DTV transition.)

The next factors are based on the signal path to your antenna.  Distance from the transmitter is a major factor (closer is better).  TV signals travel in nearly straight lines, so any natural or man-made objects in the signal path can block it.  If the receiving antenna is inside a building, the building materials (especially metal ones) can block signals.

At the location of the receiving antenna, these factors affect reception, and you may be able to control some of them:

• height of the antenna (higher is better);

• direction the antenna is pointed (digital TV signals are more sensitive to antenna direction; a directional antenna should be pointed at TV transmitters);

• the "signal gain" of the antenna (more sophisticated antennas can multiply the power of the received signal; this is called "gain");

• the length of the antenna wire from antenna to TV (shorter is better), and

• the quality of the antenna connections all the way to the TV. 

While the antenna factors may be easy to control for one TV channel, most viewers need their antennas to work for many local channels.  That increases the challenge of setting up the antenna, as you need to try all the stations for each antenna position you test.

There are two kinds of antenna connections on TVs.  To connect antennas, modern TVs use a small round jack called a "screw on" or "F type" jack.  This has a center hole for the signal wire.  Most modern antennas, as well as connector cables from TV converter boxes, have plugs that fit these antenna jacks.  The antenna wire used with these connections is a round cable, called a "coaxial" cable.  The cable has a metal shield inside, to protect the antenna signal from outside interference.

TVs more than 20 years old may have either two antenna screws (for a combination VHF/UHF antenna), or two sets of two screws (one set for a VHF antenna and one set for a UHF antenna). 

Older antennas have "twin lead" flat wires that connect directly to the screws.  Although the "twin lead" system has been replaced on newer TVs and antennas, there are still older TVs that have them. 

If you need to connect a round antenna cable to the two screws on an older TV, you use an inexpensive "matching transformer" with an "F type" jack and the 2 wire output, which you can buy wherever TV accessories are sold.  And if you need to connect a "twin lead" antenna wire to a modern TV, you use a different "matching transformer" that has two antenna wire screws and a "coaxial" output plug. 

How should you try a TV antenna?  The following steps discuss TV antennas from "simplest" to "most effective."  After reviewing these, use the antenna resource at the end to decide what type of antenna to try. 

Indoor antennas. 

1.  "Rabbit ears" antenna.  The simplest and cheapest TV antenna for most viewers is the basic "rabbit ears" antenna.  If it is a "VHF/UHF" antenna for all TV channels, it has long arms that can be tilted and pushed in or out (these are for VHF channels 2 through 13) and a small, round antenna in the base, which can only be adjusted by turning the entire antenna (this part is for UHF channels 14 through 69).  You will also find more modern designs for indoor antennas.  If your location is 15 miles or less from TV transmitters, this antenna might give good results on local digital channels. 

There are new, "flat panel" indoor antenna models that are shaped like a picture frame; these can be laid flat on a table or shelf, or hung on a wall.  They have modern circuits inside for good digital TV reception. 

2.  Indoor "amplified" antenna.  This is similar to the "rabbit ears" indoor antenna above, but it has a signal amplifier built in.  If you can afford this antenna, it is a good way to start your test since it can provide a stronger signal to the TV.  (Amplifiers can add unwanted "signal noise," but it won't show up in a digital TV program). 

Outdoor antennas.

3.  Simple outdoor antenna.  Reception can improve dramatically with a simple outdoor antenna.  Ideally it should be mounted so that it can be pointed in the direction of the greatest number of local TV transmitters, with the fewest objects in front of it.  It can be mounted on a roof or chimney. Simple UHF-only antennas are very flat.  Combination VHF/UHF antennas can be several feet long.

Outdoor antennas can be placed in an attic, but that is a compromise; roofs shield some of the signal, metal items like vents can affect antenna reception, and if there is not much room, it may be difficult to "aim" the antenna for best reception. 

4. "High gain" outdoor antenna.  If you are 30 miles or more from TV transmitters, you may need more sophisticated antennas with "signal gain."  These antennas can be very sensitive to TV signals in the direction they are aimed, but they have many more parts, or "elements" and are larger, longer, and heavier. 

Two upgrades that you or an installer might try with outdoor antennas are 1) adding a signal amplifier in the antenna line, and 2) installing the antenna on a rotator that will turn the antenna and point it at the TV transmitter you are watching. 

Outdoor antennas should be installed with care, and professional installation is recommended.  Antennas need to be located away from power lines or other hazards, and they must have a proper electrical ground installed outside the home.  Also, working on rooftop areas can be dangerous.  Right now it may be harder to find professional antenna installers; most electronics stores haven't offered this service for years. With the new interest in TV antennas, many satellite dish installers and home theater retailers may add antenna installation to their services.

For more information, an excellent antenna planning resource is www.antennaweb.org, sponsored by the Consumer Electronics Association and the National Broadcasters Association.  It will calculate the direction and distance of digital TV transmitters from your address and recommend the types of antennas you should try.  More details on choosing and installing an antenna can be found at  www.hdtvantennalabs.com. 

Are you ready to try receiving digital channels with your antenna?  Make a list of local TV stations broadcasting in digital (there's a list on this website).  Each station will have two channel numbers:

• the "tuner" channel (this is usually the same number as the station's analog channel; you will see this number on your digital TV tuner), and

• the "RF" or "radio frequency" channel, which is the actual radio channel the station uses to transmit the TV signal.

See how many stations your digital TV can tune (some have an "auto-tune" or "scan" feature, which will find the channels automatically).  Some TVs and DIGITAL CONVERTERS have a signal strength meter for the channel.  You can move or turn the antenna to get the strongest signal for each channel.   Digital channels will either have great reception (a perfect picture) or bad reception (a picture with parts that freeze, or a message that says "no signal/low signal").   (But remember: some digital stations are not running their full power until June 12, 2009.) 

Take notes on what antenna position you use to receive each channel.  Your goal is to receive all or most of the local digital TV channels with your antenna in one position that doesn't have to be changed.  If you can't do that, you may have to try a better antenna solution.  As noted earlier, antenna reception is part physics and part magic, and you'll have to experiment.

Many antennas say "HDTV."  Do I need one of those?   It won't hurt.  Actually, there is no such thing as an "HDTV" antenna.  "HDTV" is used in antenna marketing to suggest that the antenna should deliver a good overall signal.  Digital TV signals, like analog signals, work best when the antenna picks up a strong signal and sends it to the TV.  

I live in a covenant-controlled community that restricts outdoor antennas.  Can I put up a TV antenna?  Possibly. The Federal Communications  Commission prohibits homeowners and similar associations from restricting the installation, maintenance, and use of antennas used to receive local broadcast TV by owners and renters who have "exclusive use" areas where they could install such antennas.  This is part of the same ruling that forbids homeowners associations from preventing residents from installing satellite TV dishes.  Thus, many viewers living in areas with antenna restrictions may have the right to install outdoor TV antennas.  For more information, go to www.fcc.gov/mb/facts/otard.html.

What stations will I get with a TV antenna?  You should get all the local TV channels that have a signal strong enough to reach you.  This includes:

• "full power" TV station analog signals (that will go off by June 12, 2009)

• "full power" TV station digital signals, including "multicast" extra channels, and

• "low power" and "translator" stations that will continue to broadcast analog signals next year.
  

You will not get "cable" or "satellite" networks unless they are carried on a local digital TV channel. 

I have an indoor antenna, but I have to turn it to receive different digital channels.  That's not convenient!  See if you can position your indoor antenna higher, or get one with an amplifier, or get one that's flat and receives signals from all directions.  If that doesn't work, you should consider an outdoor antenna. 

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CAPITALIZED WORDS are defined in the Digital TV Glossary.