SEARCH *** Columbia ISA Audio/Video
and UHF - Analog TV and Digital TV
In the United States, television stations broadcast over the air in the
VHF and UHF portions of the electromagnetic spectrum. VHF stands for
Very High Frequency.
Stations in the VHF band include TV channels 2 through 13. UHF stands
Ultra High Frequency. Stations in the UHF band are the television
channels 14 to 69.
In 1952, the FCC allocated 70 additional channels above the VHF
television band and called them "ultra high frequency" or UHF band. The
channels are 14 through 83. UHF signals, however, due to the physics of
radio frequency transmission, are inherently less efficient in the
conversion of radio waves to the electrical signals used by the
television receiver, and are subject to more losses from some
environmental conditions than VHF. Good UHF reception, therefore,
requires more attention to antenna installation and set tuning than
does VHF reception. On the other hand some VHF channels are subject to
certain types of interference to which UHF channels are generally
If UHF reception in general is bad, how it's bad can help determine the
problem. "Snow" is visual noise caused by a weak signal. poor antenna
system, the set itself, or a combination of these. "Ghosts" or multiple
images are caused by a signal arriving from two or more directions
simultaneously reflected off buildings, trees and mountains. A good
antenna system often solves these reception problems. An outdoor
antenna is better than an indoor antenna. An indoor antenna is better
than no antenna at all. If an outdoor antenna is needed for VHF, you'll
almost certainly need an outdoor antenna for UHF. But if good VHF
reception can be obtained with and indoor antenna, a loop or other UHF
antenna on the set may also work.
All indoor antennas can be adversely affected by the walls of a house,
inadequate height, and by movement of people in the room-as may be
noticed with VHF "rabbit ears." Loop or single bow tie UHF antennas are
usually not satisfactory. They are difficult to adjust for maximum
signal pick up or for elimination of ghosts. Be sure their lugs are
secure to the UHF antenna terminals on the back of the set. The indoor
combination VHF/UHF antenna has a multi-position switch to get the best
picture. As a rule, this type of antenna is not good for UHF. The rod
antenna, or "monopole," is a VHF/UHF antenna found on some portable
sets, Normally UHF reception is poor, but can be enhanced when the rod
is telescoped to its smaller size.
Best Indoor Antenna
If an indoor UHF antenna must be used, the two-bay bow tie with a
reflector screen is the best choice. But, keep in mind, outdoor
antennas are always better than indoor antennas. Make sure the antenna
wires are connected to the UHF terminals on the back of the TV set.
There are many different kinds of outdoor antennas available in a wide
price range. The kind selected is determined primarily by the
geographic location of the receiver.
Recommended UHF antennas
* Four-way bow tie for metropolitan areas with strong signal
* Eight-way bow tie for suburban areas with medium signal
Television signals are strongest when the station transmitting tower
and the home receiving antenna are in line-of-sight. If the
line-of-sight is blocked or weakened by mountains, buildings or trees,
the signal, likewise will be weakened or lost. The signal will also
grow weaker as it travels farther.
"Gain" is the measure of an antenna's sensitivity - and its ability to
pick up signals. It is measured in decibels (dB). The farther away from
the station tower, the more gain the antenna should have. Gain can also
vary from channel to channel. For example, an antenna's advertised gain
rating may be at Channel 20, but the gain may be much less at Channel
69. Make sure the dealer guarantees that the antenna purchased is for
channels in your area.
Where buildings or other obstructions cause "ghosts," an antenna with
good directivity is recommended. Directivity is the ability to receive
only those signals at which an antenna is pointed. Highly directive
antennas have narrow receiving angles (measured to degrees) and high
"front to back ratios." To insure the best reception aim the antenna
If a good VHF antenna installation is already on hand, it will probably
be less expensive to add a good quality UHF antenna on the same
mounting mast, The separate UHF antenna also will permit pointing
VHF and UHF antennas independently.
If all television signals are coming from the same direction, both VHF
and UHF reception can be improved. Choose an antenna according to the
distance to the most distant UHF station for which reception is desired
by installing an all-channel combination antenna. Combining both
antennas in a single mechanical structure imposes design problems which
make the selection of a well-engineered antenna very important.
There are several good combination VHF/UHF antennas available. One of
the best types combine a "log periodic" VHF antenna with a "yagi" UHF
antenna on a single horizontal boom. If the UHF stations to be received
are located in different directions from the house (more than 30
* Either use separate antennas with a mixer or a switch (get
professional help for this kind of installation.)
* Or use an antenna rotator with remote control. The rotator is ideal
when signals come from many directions.
A good lead-in line installation delivers the signal from antenna to
set with relatively little loss of strength. Choose a quality grade of
either one. Flat ribbon twin lead, shielded twin lead and solid core
coaxial cable don't work well for UHF. Lead-in lines deteriorate over
time. Lead-in lines over five years old (or less depending on
environmental conditions) should be replaced with new cables.
* is initially less expensive.
* has moderate to poor life; signal loss increases as it weathers and
* foam filled type works best.
Coaxial Cable (75 ohm line)
* costs more initially, but less frequent replacement makes it less
costly in time.
* occasionally needs matching transformers at antenna and set, and uses
* special connectors.
* lasts much longer, Has slightly more signal loss than new twin lead,
* loss doesn't increase with age.
* foam core works best.
* is better at screening local interference.
* looks better.
A good installation can be made using either type of line. Get
professional help if you have special problems like local interference
or very weak signals. Few TV sets still have 300 ohm antenna
matching transformer to connect coaxial cable to the set will be
With separate VHF and UHF antennas, separate lead-in lines are used to
connect them to their respective terminals on the television set. Most
combination VHF/UHF antennas have a connection for a single lead-in
line, and in most locations a single high quality lead-in line will
deliver good VHF and UHF signals. However, a single line cannot be
connected to both the VHF and UHF 300 ohm terminals Instead, a good
VHF/UHF "splitter"-rated 300 ohms for twin lead or 75 ohms for coaxial
is required. Connect the lead-in line to one end, and the two pairs of
wires at the other end to the appropriate set terminals.
Splitters (also called "mixers") can also reduce signal strength. So in
a weak signal area, use separate lead-ins or add a booster amplifier to
the antenna. If a booster amplifier is added, it should be in the line
before any splitters, and as close to the antenna as practical.
The Best Antenna Location
* Higher is usually better. Six to eight feet above the roof should be
* Buildings or other obstructions shouldn't block the line-of-sight to
the TV tower.
* The shorter the lead-in line, the less signal is lost.
* Avoid attaching the antenna to a working chimney.
* Fumes are harmful to the aluminum antenna parts.
* Heed local ordinance.
* The dealer can advise what hardware to use to mount the antenna.
* Be sure the antenna is assembled correctly. Read the instruction
* Check the area to be sure there are no power lines nearby that could
touch the antenna, lead-in lines, or metal extension ladder.
* Ground the antenna mast electrically, using No. 6 or larger wire and
standard ground rod to help protect the antenna and TV set from
* Masts taller than 10 feet need guy wires.
* If a separate UHF antenna is used, mount it 4 or 5 feet above the VHF
* Aim the antenna at the TV station tower. Where this is not feasible,
a signal reflected from a large building or other obstruction may work.
* Experiment with antenna height and aiming, because a few inches can
make a big difference. Have someone watch the set and report of
reception quality as the antenna position is changed.
* Keep lead-in line free of splices and sharp bends.
* Keep twin lead at least three inches from metal gutters and pipes by
using "stand-off" devices every three feet.
* Don't run twin lead and rotator wires through the same stand-offs.
* If a rotator is used, leave enough slack in the lead-in line for
rotating the antenna.
* Secure twin lead to stand-offs or tape coaxial cable to the mast to
avoid strain on antenna connections.
* Twist twin lead 1/2 turn per foot to prevent wind whipping and to
reduce FM or other interference.
* Form the lead-in line into a half loop where it enters the house, so
rain water will drip off. Seal the entry with a waterproof material.
* Excess line coiled in the wall or behind the set can cause signal
loss and interference.
More than one television set (or FM radio) may be connected to one
antenna by using a multiple set "coupler." Most couplers weaken
signals. If signals are weak a coupler and an amplifier may be needed,
which substantially increased the cost. It may be cheaper to erect a
All televisions sets, particularly older ones, add some noise or "snow"
to weak UHF signals. A booster (or preamplifier) may reduce the snow,
but first be sure a good antenna installation is in place. Keep in
mind, outdoor booster antenna are more efficient than indoor models
mounted at the set.
Regardless of initial quality, antennas and lead-in lines gradually
deteriorate with age. Pollutants and salt ocean air are particularly
destructive. Check the complete installation and hose the antenna with
Cable TV Systems
Cable systems rarely carry a UHF station on its own UHF channel. UHF
stations are usually transmitted either on an unused VHF channel or on
one of the special cable channels available through a set-top converter
furnished to the subscriber. The cable company will provide a listing
of channels to which the UHF channels have been converted.
Broadcast television stations transmit their signals out over a wide
area, typically up to 60 miles, from tall towers with an antenna at the
top. The tower
is the steel structure that holds the antenna in the air. Sometimes
transmitting towers are located on hill tops or tall buildings to
There are two major factors that determine the coverage area of a TV
station. The first factor is the height of the station's transmitting
antenna. To keep the broadcast stations on a somewhat level playing
field, the FCC has a limit on maximum antenna height. TV stations west
of the Mississippi are restricted to a height of 2,000 feet above
The second factor that defines coverage is the effective
radiated power (ERP) measured in watts. UHF TV stations operate at a
higher frequency than VHF. It
requires a greater amount of power output for UHF stations to match the
coverage area of a VHF station. The FCC limits the maximum visual ERP
to 100,000 watts for VHF channels 2 through 6. VHF channels 7 through
13 are permitted a maximum visual ERP of 316,000 watts. UHF stations
are permitted a visual ERP of 5,000,000 watts. To receive a UHF TV
need an antenna designed for UHF reception. To receive a VHF TV signal
you need an antenna designed for VHF reception. Many antennas combine
VHF and UHF into one antenna but use different parts of the antenna for
VHF and UHF.
In 2009, many TV stations in the U.S. shutdown their
analog TV signals and instead, broadcast digital TV signals. In
addition, many of these TV stations will move from VHF channels to UHF
channels. The same bands of VHF and UHF frequencies will be used to
send signals out but with digital TV signals. An analog TV will not be
able to directly receive digital signals because analog TV sets have a
built-in NTSC TV tuner. The NTSC tuner is designed for analog signals.
Digital TV signals will need an ATSC TV tuner. Most TV sets sold after
2007 have a built-in ATSC TV tuner designed to receive digital TV
signals. To watch digital TV on an analog TV set, you need a converter.
The basic converter box will receive local broadcast digital TV
stations and convert the signals to analog, showing up on VHF channel 3
or 4 on the analog TV.
The same VHF/UHF antennas are used to receive digital TV signals as was
used to receive analog TV signals. There is no such thing as a HDTV
antenna. Advertising and marketing is very misleading in this regard.
If you have a VHF or UHF antenna, you may not need to buy anything when
digital TV arrives. However, digital TV signals do present some new
challenges which MAY require you to buy a better VHF/UHF antenna.
antenna should I buy?
Two of the more established TV antenna
vendors are Channel
Master and Winegard
but you can buy from local dealers as well. Exactly which
antenna you should buy depends on your local conditions so it is almost
impossible to say without knowing all your local factors. You may have
a VHF station in your area along with several UHF stations or you may
only have UHF stations so you would not need a VHF antenna. Your TV
stations may be in different directions or all in the same direction
and so on.
What if I have both analog and digital TV stations in my area?
One of the features of some of the converter boxes available in 2009 is
the so called ANALOG PASS-THRU feature. If you live in an area where a
local TV station is going to remain broadcasting in analog or is a
low-power TV station which does not have to convert to digital in 2009,
you can select the analog pass-thru feature on the converter box and
tune in channels on the TV set instead of the converter box. The
converter just passes the signal on thru from the antenna without
converting and your analog TV tunes in the channel as in the past. You
do not have to modify your antenna installation. You can switch back
and forth depending on which channel you want to view.
Television signals are strongest when there is a line of sight between
the transmitting tower and the home-receiving antenna. The signal is
weakened when buildings, hills, and trees block the line of sight.
Signal strength also decreases as the distance from the transmitting
tower is increased.
Gain and directivity are two important specifications to check
when selecting a TV antenna. Gain is measured in decibels (dB). It
indicates the antenna's sensitivity. There is a greater need for gain
the farther you live from the TV tower. If you live close to
the tower, a "local" or "suburban antenna" with a gain of 5 to 9dB
should do the job. A "near
fringe or fringe" antenna has 8 to 10dB of gain. If you live 30 to 35
miles away, consider a "deep fringe" or "far fringe" antenna
with 11 to 16dB of gain.
Directivity indicates the antenna's ability to receive only the
signals in the direction the antenna is pointing. The spec is measured
in degrees. The smaller the number the greater the directivity. A
highly directive antenna will have a narrow receiving angle to
eliminate signal reflections that can result in ghosting. (Faint double
images that appear on the screen). Alignment is critical and may take
more time with a directive antenna. A movement of inches can
dramatically improve or degrade the signal. Use a directional antenna
if ghosting is a problem in your area.
contain a built-in amplifier to boost the signal. The spec sheets often
list the gain of the amplifier, not the gain of the antenna. If the
signal is weak leaving the antenna, it will contain noise.
The built-in amplifier will not clean up the signal. It will amplify
the noise along with the signal. The appropriate solution is a larger
antenna with an increased amount of gain.
antennas are often better than indoor antennas. The mechanical details
of an outdoor antenna installation depend upon the selected antenna and
the available site. Shops that sell rooftop antennas offer a wide
variety of hardware to secure the antenna to any structure. Consult
with the shop's sales staff to select the appropriate hardware for your
particular situation. Think about having your antenna
professionally installed if you feel uncomfortable about working on a
Here are a couple of general comments about antenna
installation. The rooftop is a good location because it is a
cost-effective place to obtain the necessary height. As a general rule,
higher is better. Six to eight feet above the roofline is usually
adequate. Keep the antenna as far as possible from tree limbs, power
lines, and any electrical equipment. If the house is located near a
heavily traveled highway, the antenna should be placed on the far side
of the house away from the highway. The antenna and its mast should be
Fully extend all elements of the antenna. The antenna should be
positioned with the horizontal elements at right angles to the TV
tower. Point the short elements toward the location of the TV tower.
(Refer to the section
on Antenna alignment). Connect the antenna to a television to check
reception. If it is unsatisfactory, the antenna will have to be moved
or rotated until a strong, reflection-free signal is received. Once the
antenna is aligned, it should be locked down tight to prevent it from
moving in the wind.
best option is to place a full size antenna in the attic. This approach
has many limitations. The physical space may not permit optimum
orientation. Attic antennas may not provide enough height to clearly
receive the signal. Structural elements of the house can block and
reflect the signal like metal roofs and metal solar heating protection
under your shingles. They will block the signal completely and make an
attic antenna useless.
If you are installing an antenna in your attic, locate the antenna in a
place where all of the elements can be fully extended. It is important
to find a spot where the antenna can point to the TV tower. If there is
enough room, experiment with different places in
the attic. Sometimes the movement of only a couple of feet can make a
world of difference with the quality of reception.
expensive antennas are the indoor, set-top variety. If your television
set was not
provided with an indoor antenna, there are generally four types
available for purchase.
is the least expensive. It is quite literally a round wire loop.
On older television sets, the loop connects directly to the UHF
terminals on the back of the set. Make certain that the UHF lugs are
antennas are slightly more expensive than loop
antennas. The antenna consists of a wire bent in the shape of two
connected triangles, hence the name "Bow
Tie". The bow tie is often times
clipped to the telescoping pole on a set of rabbit ears.
consist of two telescoping poles that stand
up like a "V". Some UHF-VHF rabbit ears have a round loop sitting near
the base of the "V". UHF is received with the loop. Rabbit ears without
the UHF loop usually provide disappointing UHF reception.
is a single telescoping rod that
is usually built into a portable television. Normally, UHF reception is
poor, but it can be enhanced when the rod is telescoped to a smaller
Older analog TV sets have separate connections for UHF and VHF
antennas. If you are
using a loop or bow tie with an older set, make certain the antenna is
connected to the UHF terminals with the lugs tight and secure.
For best results, locate the indoor antenna near a window, away
from electrical sources. You will need to experiment to find the best
orientation and placement. It can take a considerable amount of
manipulation to optimize for best reception. The movement of people in
the room can affect the signal. Indoor antennas usually require
adjustment as you switch from station to station. Most people are
disappointed with the performance of inexpensive indoor antennas but if
your local TV signals are strong enough, these types of antennas work
A typical TV station broadcasts from a 1,500-foot tower located about
10 to 20 miles from downtown. If the town has several TV channels,
chances are that many of them are located in this same area. If you
combined VHF-UHF antenna, point your antenna in the same general
direction for all of the TV stations. If you have one or two TV
stations located in a different direction, you may need to invest in a
TV antenna rotator. This device has a motor to rotate the antenna under
remote control. This allows you to change directions until your
reception improves. Do not point your antenna in the direction of the
TV station's studio. Chances are their signal does not radiate from the
Consider a separate UHF antenna if you are receiving a snowy or
ghosty UHF signal with clear VHF reception. A good quality UHF antenna
is optimized for the UHF band. Shop for a high gain and highly
directive UHF antenna. The separate antennas will permit you to point
both antennas independently for best reception instead of "splitting
A good TV picture is the result of many variables including a strong
signal broadcast from the TV station, a good antenna and antenna wire,
a sensitive TV tuner, a good cable from tuner to TV set, and a good TV
set. Any link in the chain which is inferior can produce a bad picture.
Installing an Antenna for Digital TV
There is no single antenna or antenna type that will deliver excellent
TV reception in every location. The main factors determining reception
are the distance and direction from the TV station transmitters to your
home receiving location. Other factors include the transmitter's power
and the height of its tower, the terrain between the tower and your
antenna, and the size and location of any large buildings in the path
of the TV transmission.
If you live within a few miles of the TV transmitter, and the signal
path is relatively unobstructed, you may be able to get adequate
reception using a small set-top indoor antenna. But as you move farther
away, getting usable signal strength becomes more difficult. This is
where careful antenna selection and installation become essential.
Keep in mind that even in the same neighborhood reception conditions
often vary from house to house. For that reason, it's best to purchase
your antenna from a dealer who offers no-hassle returns with a
VHF and UHF
Like analog TV signals, digital TV signals can be broadcast over two
different frequency ranges: VHF (Very High Frequency) and UHF (Ultra
High Frequency). The VHF channel range is 2-13 "low-band" VHF is
channels 2-6; "high-band VHF is channels 7-13. The UHF channel range is
14-69. Prior to the 2009 transition, most digital stations broadcast in
the UHF frequency band, meaning that most viewers would be fine using a
UHF antenna. But many stations will change their channel locations with
the digital transition.
The nation's 1,819 full-power TV stations will look like the following:
* Low-band VHF (ch. 2-6): 40
* High-band VHF (ch. 7-13): 445
* UHF (ch. 14-51): 1334
If some of the local stations you want to receive are below channel 14,
you may need a VHF/UHF antenna. The FCC requires digital stations to
embed a "reference" to their analog channel so viewers won't have to
memorize a whole new set of channel numbers. So, your TV might identify
a digital station as being in the VHF range when it's actually in the
Example: A TV station broadcasts digitally on channel 55 but it shows
up as channel 5 on your TV because channel 5 is the old original
What is the difference between UHF and VHF antennas?
Antenna elements are based on the size of the waves they're designed to
receive, and VHF frequencies are lower than UHF so the waves are
longer, requiring a larger antenna surface to receive them.
Uni-directional vs. multi-directional TV antennas
Antennas described as "uni-directional" or sometimes just "directional"
are designed to receive signals from one direction. "Multi-directional"
or "omni-directional" antennas are able to receive signals from all
Directional antennas are able to pull in signals from greater
distances, and because they "see" in only one direction they are
resistant to noise and "multipath distortion" (a problem created when
an antenna receives reflections of the desired signal). Because
multi-directional antennas "see" in many directions they are more
likely to pick up noise, interference, and multipath distortion.
What digital TV
stations are in my town?
Use the tools located here:
and "ENTER YOUR ZIPCODE" to locate your desired TV stations, this gives
you an accurate picture of their direction in relation to your home. If
all of those stations are transmitting from an area covering a range of
20° or less, you can probably receive them using a
uni-directional antenna. If the transmitters are positioned more than
20° apart, try a multi-directional antenna. As an alternative
to a multi-directional antenna, you might consider combining a
uni-directional antenna with a "rotor," which lets you remotely rotate
the antenna to pick up stations in multiple directions. A rotor is
capable of moving your antenna around in a circle in order to capture
TV signals better. You mount the antenna on the rotator motor and the
motor on a vertical shaft usually on your roof. Then from inside the
house you can control the direction of the antenna, rotating it to get
a better signal.
Also try here for all TV stations in your state and town with a map
showing locations of TV towers:
TV stations database, USA and Canada
This site shows you all the TV stations in your area with an abundance
of other information. Their signal analysis tool shows each TV station
with their locations relative to your location, their output power and
vs. Outdoor antennas
The indoor antenna, with compact receiving elements that are under 12
inches long. The outdoor roof-mount, which has 33 elements and measures
over 8 feet long.
Indoor antennas are generally small, designed to be placed on or near
your TV. Outdoor antennas tend to be significantly larger and are
intended for roof- or attic-mounting. In general, the larger an
antenna's surface area is, the stronger the signal it will provide. The
relative strength of the signal an antenna can deliver to a tuner is
referred to as "gain" and is measured in decibels (dB). The higher the
dB rating, the greater the gain.
Nearly all outdoor antennas perform better than even the best indoor
antennas. Along with their size disadvantage, indoor antennas have a
height disadvantage, and are adversely affected by the walls of a house
and even by movement of people in the room. Other sources of household
interference include fluorescent lights, computers and cordless phones.
One way to help antennas overcome size or height disadvantages, or
otherwise enhance signal gain, is through the use of electronic
amplification. The amplifier can be built in as it is in many indoor
antennas, or it can be a separate device that installs in-line between
the antenna and TV. An amplifier that installs on an outdoor antenna or
mast is often called a preamplifier or "preamp." Most experts recommend
only using an amplifier if you need to. The potential drawbacks of
amplifiers are that they amplify noise along with the signal, and they
can be overdriven by strong signals, which can make reception worse.
If you know of any neighbors who are using an antenna, find out what
type/model it is and how well it performs. You could also try calling
local TV stations with your antenna questions. It's definitely in their
interest to help their viewers improve reception.
Antenna cabling: always use 75-ohm coax cable RG-6
Whether you want to install an antenna on your roof, on a pole, or in
your attic, using the right kind of cable is crucial. The two types of
wire commonly used to connect an antenna to a TV are 300-ohm twin-lead
and 75-ohm coax. Twin-lead is a flat wire, while coax cable looks like
the round cable installed in homes for cable TV service. In recent
years, virtually all TVs have gone to the coax-style connection.
Coax cable is superior to twin-lead in every way and should be used if
possible. Even if your home has an existing run of twin-lead cable,
consider replacing it with coax. Twin-lead is not shielded and the
entire length of wire can act like an antenna, which may cause
reception problems. Coax cable is shielded, which prevents signals from
leaking into or out of your system. Coax cable is also unaffected by
your home's electrical wiring or by contact with metal objects. And
coax has a much longer lifespan than twin-lead.
Antenna cabling tips:
* For the best performance and reliability, use high-quality UL-rated
dual- or quad-shield RG-6 cable
* Cable should run as directly as possible from the antenna to the
tuner; try to minimize the number of splices
* Avoid sharp bends in the cable as they can impair performance
* If the antenna is installed outdoors (including on the roof) run the
cable into the house through an attic or basement if possible; never
run the cable through a window or door
* Outdoor antennas should be grounded for lightning protection. Place a
grounding block where the antenna cable enters the house and run a wire
from the grounding block to your home's ground rod. This is not only an
important safety consideration but also a potential code requirement
* Outdoor connections should be protected from exposure to the elements
by applying silicone grease to the connection and covering it with a
Tips on installing
an outdoor antenna
Large outdoor antennas can be installed on a roof or a free-standing
pole, and many can be installed in an attic. For the best results, your
antenna should have the clearest possible "view" of the transmitter
tower. That is achieved with a roof- or pole-mount installation.
People living in neighborhoods with homeowners' associations may wonder
if association covenants can restrict antenna use. The
Telecommunications Act of 1996 prohibits restrictions that impair the
installation or use of antennas to receive video programming. It covers
digital satellite dishes, TV antennas, and wireless cable antennas.
Most TV antennas designed for roof- and/or attic-mounting include a
mounting mast. Here are some general tips for roof-mount antenna
* Locate and avoid power lines and other wires in the work area
* Do not climb on a wet or icy roof
* Do not attempt high installations on windy days
* Do not climb onto a roof when there is no one else around
* Do not install an antenna under large, overhanging tree branches if
it can be avoided
* If possible, avoid chimney-mounting an antenna as smoke and gases
from the chimney can impair the antenna's performance and shorten its
When you're aiming the antenna, use a compass to ensure your antenna is
accurately and precisely oriented toward the signal source. At this
stage, it's best to have a helper who can check picture quality and
relay the information to you. (Most, but not all HDTVs and HDTV tuners
include an onscreen signal strength meter.) Be sure to check the
picture on all channels you want to receive before securing the antenna
If you plan to use an antenna in addition to a digital satellite TV
system, you have a couple of options. One fairly easy solution is to
attach a "clip-on" antenna to your satellite dish. Some VHF/UHF
antennas have built-in "diplexers" that combine the satellite and
antenna signals onto a single cable, which can eliminate the need to
run new cable. You'll need to install a diplexer at each satellite
receiver to provide separate connections to the "Satellite In" and
"Antenna In" jacks. A clip-on antenna usually performs better than an
indoor antenna, but not as good as a larger outdoor antenna.
Compared to roof-mounting, installing an antenna in your home's attic
has several appealing advantages: installation is much easier, the
antenna is hidden from view, and the antenna and connections are not
directly exposed to harsh weather.
The main disadvantage of attic-mounting is poorer reception. As an
example, a single layer of asphalt shingles over a standard plywood
roof creates a 30%-50% reduction in signal strength. Attic-mounting can
be an effective option in areas where strong signals are present. To
maintain adequate signal strength, an amplifier or preamp is often
Other potential obstacles to attic-mounting include a metal roof,
aluminum siding, metal gutters, or foil-backed insulation in your walls
or under the roof. Any of these conditions can result in signal
interference or blockage. If that happens, try installing the antenna
in a different location. For the best reliability and performance,
mount the antenna to a mast and don't let the antenna touch the attic
http://www.antennaweb.org/aw/Address.aspx "ENTER YOUR ZIPCODE"
Get Digital TV stations in your area.
television sets require some adjustment to receive UHF. It is important
to have your television set correctly configured for UHF or you will
not receive any signals above channel 13. It does not matter if you
have an expensive high gain antenna, if your TV is not set-up for UHF,
you will not pick-up UHF channels. Please refer to the owner's manual
of your TV set or consult a
local dealer for your type of television. Here are a few general notes
to help point you in the right direction.
Most television sets sold since 1995 are considered "cable
ready". A cable ready set is capable of direct connection to the cable
system without the use of a set-top converter box. Cable television
systems use essentially the same set of
frequencies as the broadcast stations for channel 2 through 13. Cable
systems use a different set of frequencies for channels 14 and higher.
When a television is configured for first time use, there are several
different menu selections that must be set-up. Most TV sets default to
the Cable TV (CATV) configuration. Look for a menu selection that
offers the choice of CATV or ANT. (Some sets list the choices as CABLE
or TV). If CATV or CABLE is selected, you will not be able to receive
an over-the-air signal because your television set is
looking for a cable channel instead of UHF channel. Be certain to
check this menu item for ANT or TV if you are using an outside antenna.
Some televisions default to the CATV setting if unplugged from
electrical power. Look for the CATV/ANT menu selection if you suddenly
lose the ability to view UHF signals. Check the CATV setting anytime
you move the TV or experience a power outage.
Other televisions have a Cable or CATV switch located on the
back of the set near the antenna connector. If your television set has
a switch on the back, flip the switch to ANT.
If your set is "cable ready", it most likely has a combined VHF-UHF
antenna input. Look for a round, threaded connector labeled ANT.
Cable Ready Televisions
If you bought your TV set before 1990, there is a good chance that it
"cable ready". Some of the older TVs need a fine tuning adjustment to
select specific UHF stations. The procedure may require you to tweak
tiny knobs located under a panel door located below the screen or on
the side of the set. Refer to the owner's manual of your television set
for specific instructions.
Some older television sets (late 1970s and early 1980s) have rotary
tuners. The rotary tuners use
round knobs that "click" for each channel position as the knob is
rotated. Often times there is a separate knob for the UHF band.
To receive Channel 28 for example, rotate the selector to the UHF
position on the VHF tuner. (It is usually located between Channel 13
and Channel 2). Next, rotate the UHF knob until Channel 28 is in the
active position. If the signal is not clear, rotate the fine tuning
knob. It is usually a ring that is located outside or inside the UHF
channel selector. (You may have to push in the ring as you rotate it).
Slowly move the fine tuning knob back and forth to adjust for the
television sets have a separate connection for UHF and VHF antennas.
Look at the back of your set. If it has a separate connection for UHF,
you must have a UHF antenna connected to it or else you will not
receive any television station above Channel 13. When in doubt, refer
to the owner's manual of your television.
An important element often overlooked is the transmission line. It is
the wire that carries the signal between the antenna and the television
set. Transmission lines deteriorate with age. If your transmission line
is worn-out, you may be looking at a snowy, ghosty signal even if the
antenna and television are brand new.
For optimum performance, a transmission line should be replaced
every five years. That statement does not mean that you should change a
five-year-old line if you are satisfied with the existing reception
quality. Just be aware that the condition of your transmission line has
a major effect on any over-the-air reception. It should be considered
for replacement any time that the antenna is properly aligned and
over-the-air reception is "not what it used to be".
If you are installing new transmission line, it is important to
select a quality grade to minimize signal loss. Round coaxial cable and
flat twin lead are the two basic types of transmission line. Twin lead
cable is less expensive, but it deteriorates faster and is more
susceptible to interference. The RG-6
coaxial cable is highly recommended. You should switch to the coaxial
cable if you are having reception problems with the twin lead
Here are a few tips about transmission line installation. Use the most
direct route possible between the antenna and the television set. Long
cable runs result in signal loss. The shorter the cable, the better the
signal. The line should be kept as far as possible from electrical
equipment, even if it means a longer cable run. One continuous piece of
cable is best. Keep the line free of splices and sharp bends.
Weak signals show up as a snowy picture on analog TV sets and on
digital TV channels as dropouts, pixelation or blank screens. A
near the antenna can eliminate or reduce the snow or pixelation. Signal
deteriorates as it travels down the transmission line to the TV. A weak
signal will be non-existent when it reaches the television unless it
receives amplification before the trip. The pre-amp boosts the signal
to offset any loss from the transmission line.
An amplifier only prevents additional signal deterioration. If the
signal is noisy leaving the antenna, the amplifier will amplify the
noise along with the signal.
multiple sets often use passive splitters to send the antenna lead to
different televisions. Passive splitters do not require any power to
split a signal two to four times. If your signal looks snowy, it is the
result of a weak signal. If you are using a splitter, bypass it by
directly connecting the antenna to a television set. If the signal
improves, you will need to get an amplified splitter. The amplified
splitter divides the signal and amplifies each output. Splitters can be
2-way, 3-way, even 4-way and generally cost only a few dollars.
Splitters can sometimes be used in the reverse direction as a combiner
to allow multiple inputs to a TV. When used as a combiner, only one
input can be "active" at a time, otherwise you will get interference.
If you live
close to the TV tower and receive distorted, smeary pictures,
the incoming signal is possibly too strong. The problem is easily
solved with an attenuator. It is a passive device that simply reduces
the strength of the incoming signal without losing clarity. The device
can be found at the same place that you bought your antenna.
at the television set and work your way toward the antenna. Check the
programming (or selector switch) for the setting ANT - CATV or TV -
CABLE. Change the setting to ANT or TV. If the television does not have
automatic fine-tuning, adjust the fine-tuning for the best picture.
If you are still
having reception problems, check for a loose antenna
connection on the back of the TV. If everything is secure and tight,
examine the condition of the line. Transmission lines can suffer damage
from hungry pets and vacuum cleaners. A nicked section of line should
be repaired or replaced. If everything looks fine behind the TV, grab a
ladder and head outside.
Loose connections and damaged antenna elements will be readily
obvious by a visual inspection. Make certain that all connections and
fasteners are tight and secure. Look for frayed wires, corrosion, or
other evidence of deterioration. Check the orientation of the antenna.
Windstorms can blow the antenna out of proper alignment.
Breaks or short circuits in a transmission line will cause a
reduction of signal strength. Lines that are loose from their
fastenings may swing against other objects causing changes in the
picture intensity. Secure the transmission line and repair any
chaffing. Replace the transmission line if it is in bad shape.
Wind, hail, and ice are the most common cause of damaged
antenna elements. In most cases, it is better to replace the antenna if
there are several broken elements. Even if the elements can be
reconnected, the performance will never be as good. Clean any corrosion
found on the antenna connectors. The corrosion on the terminals can be
removed with steel wool or an emery cloth.
The entire outdoor antenna system should be visually inspected at least
once a year.
you are having interference problems, see the following link offered
by the FCC.
Cable connections and hookup wiring
over 100 hookup diagrams
In some cases, if you are getting fairly strong signals from local TV
towers, you can construct your own TV antenna from common materials.
One example is an antenna made from an aluminum can such as a 7-UP can
or beer can. The can is cut in half, top to bottom and placed on a
wooden support piece such as a piece of wood 1.5 inches by 1.5 inches
with the open/inside part of the can covering the wood in a
semi-circle. The wooden piece is going to be in a horizontal position
with a vertical support mast which could be a broom stick or mop handle
or you could even just place the two can halves over the back of a
wooden chair. Place the two halves close together about 1 inch apart,
not touching. Connect two wires to each of the inside bottom can halves
near the center where the two can halves are one inch apart. These
could be alligator clips with wires. Connect the other end of the wires
to a coaxial cable or a balun 300 ohm to 75 ohm and depending on what
type of TV you have, or if you have a converter box, then connect to
the antenna input of the TV or converter box with coaxial cable to the
RF/ANT input. Amazingly a soft drink can or beer can arranged in this
way functions just as well or better than a small indoor loop antenna
you would buy at Radio Shack. UHF and VHF signals can be picked up and
digital TV channels come in fine. Rotate your home-made antenna for
7up can antenna made by the author was tested on VHF and UHF channels,
analog and digital, with and without a converter box. Results were
acceptable in a large metro area with TV towers 20 miles away. No
dropouts on digital channels. Digital channels were excellent. A small
indoor loop UHF antenna with a rabbit ears VHF antenna produced
slightly worse reception. Converter box used was the Insignia/Zenith
Home-made TV Antenna
Another example is
a UHF bow-tie antenna made from coat hangers, a 2X4
stud, copper wiring and an aluminum foil panel. Again, reception can be
better than a store-bought YAGI antenna. You may have the materials
lying around the house. Get a wooden stud 2X4 (which is actually 1.5
inches by 3.5 inches) about 40 inches long or whatever fits your
placement area. Studs are available at your local home building supply
store and cost just a couple of dollars if you do not have one already.
Get a cabinet door or wood panel. It could even be a stiff piece of
cardboard about 16 inches wide by 30 inches high. Cover one side with
aluminum foil and attach the panel to the 2X4 at the top with the foil
facing the 2X4.
Grounding An explanation - How
to ground your outside TV antenna
Cut 4 metal coat hangers in half and cut out the hanger
loop part so you end up with just the V from each end. Attach each half
of the coat hangers to the 2X4 edge with a wood screw and a washer so
that the coat hanger's narrow end is under the washer. You need 10
washers total. Place two V side by side on the 2X4 edge starting about
3 inches from the top of the 2X4. Now move down about 7 inches and
screw two more in place. Do the same thing with two more and then two
more. It will look like 8 cats whiskers. This is the bow-tie part. Now
connect copper wires under all the washers and meet in the center. Two
bow ties on top and two on bottom. Copper wires to connect the bow-ties
could be ROMEX 12/2 house wiring. Just make sure it is bare wire except
for the crossovers at top and bottom which must not touch. Attach a
balun to the center and your coaxial cable to the balun and then to the
TV set. Secure the 2X4 on a wooden base or to the house outside or cut
the bottom of the 2X4 so that you can insert into an antenna rotator.
If your attic is high enough, you could put the antenna up there if you
get good reception.
AUDIO / VIDEO