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Off-Air Antenna Installation Training. Overview. Why install off-air antennas Basics of off-air broadcasts Antenna Characteristics Basic Rules of off-air broadcasts DIRECTV approved antennas Safety , Preparation, and Installation Installation Considerations Troubleshooting - PowerPoint PPT Presentation
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Off-Air Antenna Installation Training
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Overview
• Why install off-air antennas
• Basics of off-air broadcasts
• Antenna Characteristics
• Basic Rules of off-air broadcasts
• DIRECTV approved antennas
• Safety, Preparation, and Installation
• Installation Considerations
• Troubleshooting
• Using Antennaweb
• Commonly Used Terms and Additional Resources
3
Why install off-air antennas
• To allow a customer to view their local area
broadcast channels either in standard or High
Definition
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Basics of off-air broadcasts
• Over-the-air (OTA) channels are broadcast by local
television stations.
• This signal is broadcast from a transmitter tower. The
signal travels in the air across the surface of the earth in all
directions within a specified area.
• There are two ways of sending the signal: analog and
digital. Analog broadcasts have in most areas been turned
off
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Basics of off-air broadcasts
• The signal broadcast from the TV tower use to cover channels 2 thru
13 (55MHz to 211MHz) & 14 thru 69 (471MHz to 800MHz) – the
Analog days
• With the move to Digital, the TV broadcasters now utilize channels 14
to 51
• Channels 52 – 69 have been re-assigned by the FCC for other purposes
• An off-air antenna is used to gather these signals and send them to the
ATSC off-air tuner which can sometimes be built into the TV its self.• Since digital TV signals are more "economical" than analog TV signals,
digital signals are able to carry more information while taking up less space as compared to analog signals. With Digital, television broadcasters have the ability to offer more features and more programming (more virtual channels) on their assigned frequency channel.
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Basics of off-air broadcasts• An ATSC tuner is required to receive digital off-air
broadcasts.
• A digital off-air tuner, which can be either the TV’s tuner or
a tuner built in to a standalone receiver, or an AM-21
• AM-21 uses a USB cable to connect to an HR21/H21 and
newer receiver
• Both the H20 and HR20 have the ATSC tuner built
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Antenna Characteristics
• There are many types of antennas available on the
market with varying characteristics. These
characteristics are usually described on the antenna
model’s specification sheet. Antennas are also grouped
by a color coding system which is useful in picking an
antenna with specific characteristics. Antennas are
usually described by their:
– Gain
– Directivity
– Beamwidth
– If it is amplified or non-amplified
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Antenna Characteristics
Gain – Describes the available signal
increase of a specific antenna when
compared to another antenna.
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Antenna Characteristics
Directivity – The antenna’s
ability to intercept signals
from one direction and ignore
those from another direction.
Directivity may be referred to
as directionality. The antenna
shown in this image is highly
directional.
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Antenna Characteristics
Beamwidth – The area from which the
antenna can receive and output signals at
approximately equal levels. This area is
described in degrees, and is formed from the
compass angles outlining the area’s
boundary. Usually, the narrower the
beamwidth of an antenna, the greater its
directivity and gain.
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Antenna CharacteristicsAmplified vs. Non-Amplified
– Amplified antennas do not increase the range of the antenna.
Rather, they should be used when the signal strength is already of
a good quality, but too much cable loss occurs by the time it has
reached the off-air tuner due to long cable runs or multiple pieces
of in-line equipment.
– An antenna that includes a signal amplifier is often referred to as
having a “preamp”. This means that the amplifier is built into the
antenna, rather than being a separate line amplifier.
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Antenna Selector Pie Chart
This pie chart is used to classify
antennas according to their
reception range and directivity.
These colors match up to those
used on www.antennaweb.org
in making a recommendation
on the antenna required to
receive a particular channel in
a particular area.
ANTENNA SELECTOR PIE-CHART LEGENDYELLOWThe smallest of TV antennas, these receive equally well from all directions. Designs include novel-shaped disks, patch antennas and antennas that attach to satellite systems. These antennas are most effective when signal strength is highest and away from reflecting structures or low areas.
DARK GREENIntermediate in both size and power, these antennas receive equally in all directions. Designs include novel stick, wing-shaped or disk-type antennas with long elements. An amplified antenna is recommended for green channels anytime a long (20 feet or more) cable from the antenna is required, or when more than one device (TV or VCR) is to be used with an antenna. They work best away from reflecting structures or low areas.
LIGHT GREENBigger in size, these antennas boast powerful reception in all directions. These antennas are better for greater distances from the signal source and areas with low signal strength. Styles include metal multi-element antennas. These antennas can be used to reject simple ghost situations. When mounted outdoors on rooftops heights (30 feet or higher), amplified antennas are best used in areas away from reflecting structures or low areas.
REDThese medium-size, multi-element antennas are the most popular rooftop antenna because of their modest size and ghost-reducing characteristics. These are best used if there are any ghost-producing reflective structures near your location.
BLUE, VIOLET & PINKThese are LARGE DIRECTIONAL antennas. (The antennas in the pink and the violet zones require a preamp)Large directional antennas can be used in all map areas yellow through blue, but may require an optional antenna mounted preamp and roof-top mounting when used in violet or pink areas.
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Basic Rules of Off-Air Reception
• Outdoor antennas are better – These antennas have a better view
of the transmitting station, receive less interference from other
equipment, and are less subject to multi-pathing from the building
structure
• Higher is better – The higher the antenna’s position, the more
direct signal it receives from the transmitting station
• Closer is better – The antenna should be on the side of the building
that faces the broadcast tower
• Bigger is generally better – The larger an antenna, the more signal
it generally receives
DIRECTV Approved Antennas
Eagle Aspen Part # DTV2BUHF
Used within Metropolitan areas < 25 miles
Winegard Sensar III Bi-directional Part # GS-1100
For use from 0 - 25 miles
Winegard Metrostar Omni –directional Part # MS2000
For use from 15 - 35 miles
• DTV2BUHF – 2BAY UHF ANTENNA (This antenna will work with the 2” mast but does not work with VHF frequency ranges channel designation 2-13)
OTA Antenna Installation
• The existing standard 2” mast with an ODU will not properly accommodate the off-air assembly.
• In many cases the installation will require a second mast to be installed at the customer’s home to accommodate the additional off-air antenna.
• DIRECTV will try to ship as many 1-5/8” masts to the affected markets as possible to aid in installation.
• The current antennas were designed to fit our previous 1-5/8” mast and only DTV2BUHF will bolt properly to the new 2 inch mast assembly.
OTA Antenna Installation
• In order to attach the MS1000D or GS1100 assembly you may be required to remove the pole clamp to enable the included U-bolt to attach to the 2” mast if a 2” mast is used.
OTA Antenna Installation
• This installation may require a self-tapping screw to keep the antenna from spinning on the pole or moving up and down on the mast.
• The other option is to replace the existing U-bolt with a 4” U-bolt
OTA Antenna Installation
• Moving forward, the antenna manufacturer will include the 4” U-Bolt along with the existing 3” U-bolt with the GS1100.
• You will need to use the longer U-Bolt when attaching the antenna to the 2” standard foot and mast or any of the other DIRECTV approved 2” alternative mounts once the option is included in the packaging.
• Please do not attach the antenna to the existing ODU mount.
• Unless absolutely necessary, a separate mount should be used for the OTA antenna.
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Safety Considerations
• Follow all safety rules and regulations you normally follow
for installation of satellite dishes. In addition to those rules:
– Locate and avoid any power lines or other wiring in the
area.
– Antennas can not be installed closer to a power line the
twice the combined length of the antenna and mast.
– Any antenna mounted on a mast 20 feet or higher
requires more than one person to install.
– The antenna mast and cable must be grounded in
accordance with the National Electric Code.
– Masts over 10 feet tall require guy wires every 10 feet.
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Steps to choose and install an antenna
1. OTA channels desired and available
2. Pick antennasto bring to thejob site(at the office)
3. Preparation and printouts(at the office)
4. Site Survey(at the customer’s home)
5. Discuss anticipated channels withcustomer
6. Assemble and mount the antenna
7. Point antenna
8. Ground antenna andrun cabling
9. Scan channels usingreceiver
10. Verify scannedchannels matchanticipated channels
11. Fine tune the antenna, if necessary
12. Clean up
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1. Determine the availability of off-air channels
If a customer expresses an interest in
receiving off-air channels, go to
www.antennaweb.org and click the
“Choose an antenna” button. This tool
predicts the off-air channels that may be
available using the address, whether
there are structures over 4 stories tall,
and the building structure. Enter the
customer’s address and click “Submit”.
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1. Determine the availability of off-air channels
Antennaweb.org provides you with a
list of available channels, the
antenna required to pick up each
specific channel, and the signal
direction for each channel. Click
here for a detailed explanation of
how to use Antennaweb.
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1. Determine the availability of off-air channels
Since the customer is interested in receiving off-air high
definition programming, click the “Show Digital Stations
Only” button. “View Street Level Map” provides a map of
the transmit station locations relative to the customer’s
address. Discuss the list of available channels with the
customer to determine if an off-air antenna can provide
the desired channels.
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2. Pick Antenna(s)
Using the street level map and channel list,
choose the antennas to bring to the
customer’s home. For this customer’s
location, a medium directional antenna
(color code red) would likely provide access
to many channels broadcast from the
north-west, but may not allow reception of
the channel broadcast from the south-east.
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2. Pick Antenna(s)
Always bring at least two or three
types of antennas with different
beamwidths, gain and directivity to
the customer’s home. Pick
antennas that should allow
reception of the desired channels
based on the information from
Antennaweb.
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2. Pick Antenna(s)
• Picking a specific color-coded antenna does not guarantee
you will receive all channels that also use that color-coded
(or smaller) antenna. The channels received are also
determined by the direction in which the antenna points.
• Additional considerations that may be evident when
arriving at the customer’s home will help you to choose
which antenna to install. These considerations will be
determined by performing a thorough site survey at the
house.
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3. Preparation and Printouts
Using antennaweb, click on “View
Street Level Map”, then click
“Printer Friendly Map”. Print the
map and the list of digital channels
for the customer’s address to take
with you to the job site. The map
and channel list will be used while
performing the site survey and
pointing the antenna.
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3. Site Survey
• The site survey should be performed using a compass and the
compass orientation provided by Antennaweb.org. If possible, the
antenna should be mounted near to the satellite dish. When
performing the survey, keep the following considerations in mind:
– Natural Obstacles (Hills, Trees, etc.)
– Man Made Obstacles (Tall buildings, houses)
– Reflective Surfaces
• Obstructions between the antenna and the broadcast stations may
cause a reduction or complete loss of signal.
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4. Discuss anticipated available channels with the customer
• Based on the customer’s location and surrounding
terrain, it may not be possible to receive all off-air
channels.
• After determining the off-air channels that will
likely to be received from the Antennaweb.org
information and your site survey, discuss the
expected channels with the customer.
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5. Assemble and mount the antenna
• Assemble the antenna following the
installation instructions that came with that
equipment.
• Find a location on the customer’s home that
has line of sight to the transmit towers.
• Install the antenna as high as possible to
avoid obstructions.
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6. Point the antenna• Peak the antenna using the highest
desired channel frequency (shown as
“frequency assignment” on the
channel list from Antennaweb.org).
• Once you have pointed the antenna,
check all desired channel frequencies
for signal.
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7. Ground the antenna and cabling run
• Both the antenna mast and the transmission line must be
grounded to meet the National Electric Code, State, and any
local requirements.
• RG-6 coaxial cable is preferred.
• Note: a single RG-6 coaxial cable must be ran from the off
air antenna to the ATSC tuner
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8. Verify available channels
Verify availability of desired channels found
using the receiver’s Local Channels scan. These
results should match what was expected from
the site survey and Antennaweb.org
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9. Fine-tune the antenna alignment
• If not all expected channels are
found, adjust the antenna’s alignment
until the expected channels are
available.
• Azimuth fine-tuning - you may need
to adjust the compass orientation
(azimuth) setting of the antenna.
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10. Fine-tune the antenna alignment
• Depending on your location and that of the
transmitter towers, you may need to compromise
how the antenna is pointed to receive the desired
channels. It may not be possible to receive all
desired channels, or using an antenna with
different characteristics (beamwidth, directivity,
gain) may be required.
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11. Clean Up
• As always, once the installation is
complete, clean up any
packaging, loose cabling, and
tools that were used during the
installation.
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Important Installation Considerations
Terrain – The landscape surrounding the customer’s home has
many impacts on their ability to receive off-air channels. For
instance, if a broadcast station is behind a large hill from the
customer’s location, it may not be possible to receive the
channel from that broadcast station. Trees and other natural
objects may also interfere with the reception of off-air signals.
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Important Installation Considerations
Obstructions – In addition to the terrain, man-made
obstructions, such as buildings and other houses, may be
between the customer’s location and the broadcast station.
These objects may prevent the signal from reaching the
customer’s antenna, or they may cause signal to be reflected,
resulting in multipathing.
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Important Installation Considerations
Multipathing – Multipathing occurs
when the signal from the broadcast
station reaches the antenna at
varying times. This often occurs
when the antenna receives the signal
sent directly from the station, but
also receives the same signal
reflected by another object.
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Important Installation Considerations
• Distance from the broadcast station – The longer the broadcaster’s
signal travels, the weaker it will be. Choosing the right antenna for
the desired channels will help.
• Digital off-air broadcasts are still in their infancy. This leads to some
additional considerations that may impact what channels the
customer may receive.
– Many broadcasters do not yet have permanent broadcast stations.
– Broadcasters are not yet legally required to provide full-time digital
signals.
– Some digital channels may not broadcast all the time.
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Troubleshooting
• This troubleshooting section lists
commonly experienced issues with
the most common resolutions.
• Match the symptom of what you are
experiencing or seeing on the screen
for troubleshooting steps for the
issue.
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Troubleshooting - Interference
Herringbones or images from another channel -
Occurs when another channel is on a close
frequency. A directional antenna may be required,
or traps and filters can solve the problem.
1. Try adjusting the antenna’s alignment or location.
2. Try using a more directional antenna.
3. Try using traps or filters.
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Troubleshooting - Interference
Co-channel interference - Occurs when
another station is broadcasting on the same
frequency, and is usually resolved by using a
directional antenna.
1. Try adjusting the azimuth of the antenna
2. Try relocating the antenna
3. Try using a more directional antenna
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Troubleshooting - Interference
Electromagnetic interference – Bright static
across the screen with a whining or grinding
noise that is often caused by appliances and
power lines.
1. If the source of the interference is outside the
home, try using a more directional antenna.
2. Try unplugging from the electrical outlet each
device in the home that could be causing the
interference.
3. Contact the power company.
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Troubleshooting - Interference
CB / Ham Radio Interference – Rolling, fading, or
disappearing picture, with the voices of the radio
operator in the TV audio.
1. If you can identify the source of interference,
contact the person and inform them of the
interference.
2. Contact the FCC if you can not identify the
source.
3. A high pass filter (one that eliminates
frequencies below 54 MHz) may need to be
attached to the input of the receiver.
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Troubleshooting - Interference
Airplane flutter – Rolling picture
or a picture that fades in and
out, often occurring when in the
flight path of low-flying
airplanes or near an airport.
1. Try using a highly directive
antenna.
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Troubleshooting
• Multipath – Multipathing occurs when a reflected signal is
received at a different time from the primary signal.
Multipathing can appear on one channel but not on others
due to the differences in frequency and wavelength of the
channel.
– Multipathing will show up as freezes in video or pixelizing.
– Avoid installing an antenna adjacent to a structure that could
reflect the signal, such as a large building or structure.
– Install a more suitable antenna for the location. A more
directional antenna will block multipath better than a less
directional antenna.
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Troubleshooting – Proper use of amplifiers
• If you have a strong signal reading at the antenna, but
have low signal by the time it reaches the receiver,
you may need to consider using an amplifier.
• Amplifiers only compensate for signal loss due to long
cable runs or pieces of in-line equipment, such as
splitters.
• If you are not receiving adequate signal readings at
the antenna, this indicates that the antenna needs to
be peaked or a different antenna may be required. An
amplifier would not help for this situation.
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Using Antennaweb.org
Antennaweb is a great
reference for picking and
installing off-air antennas.
After entering a customer’s
address, you will receive a
screen similar to the one to
the right.
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Using Antennaweb
On this screen, you have the option to see the list of all
channels, only digital channels or only analog channels,
and view a street level map of the transmitter towers
relative to the address you entered. Each channel also
lists information helpful in picking and pointing the
antenna, which is described on the next slides.
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Using Antennaweb
1. A star (*) under DTV indicates the channel is broadcasting a digital signal.
2. Antenna type is color coded according to the Antenna Selector Pie Chart, and
also lists if the antenna needs to pick up UHF or VHF signals to receive that
channel.
3. Call sign is the channel call letters. In addition to the call letters, some channels
have additional letters following the call sign. In this example, “-DT” indicates a
digital signal. You may also see “-LP” for low power, or “-CA” for Class A stations.
4. Channel is the channel number assignment that would show up in the satellite
receiver’s Program Guide. The “.1” indicates the channel has the ability to
multicast.
321 4
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Using Antennaweb
5. Network indicates the channels network affiliation.
6. City and State are the location from which the channel is broadcast.
7. Live Date may be blank if the channel is already active. It will list “TBD” if
it is not yet determined if the channel is active, a date in the future when
it is scheduled to be available, or “Testing” if the channel is testing their
digital signal.
8. Compass Orientation is the direction in which the antenna needs to
point to receive the signal. This is similar to the azimuth angle used
when point satellite dishes.
8765 6
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Using Antennaweb.org
9. Miles From indicates the distance from the address you entered to the
transmitter tower. This distance helps you to determine the antenna to
use. For instance, you could not use an antenna with a range of 30 miles
to pick up a channel broadcast from 50 miles away.
10. Frequency Assignment is the actual frequency on which the channel is
broadcast. This may or may not correspond to the channel number listed.
The Frequency assignment should be used when peaking the antenna,
rather than the channel number.
109
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Commonly Used Terms
• Amplifier – Boosts the strength of received signal but does not increase
antenna range. Amplifiers are use to account for signal loss due to long cable
runs or in-line equipment, such as splitters. An amplifier for an antenna can be
either a “line amplifier”, meaning it is installed on the coax cable running to the
receiver, or a “preamp” (preamplifier), which is built into the elements of the
antenna. Both types of amplifiers require a power inserter to be installed.
• Attenuation – A decrease in strength of a signal as it is transmitted by wires
from one point to another. Also referred to as cable loss.
• Beamwidth – The area in which the front of an antenna can intercept signals,
which is formed by the compass angles outlining the area’s boundary.
• Directivity – The ability of an antenna to pick up signals from one direction
while ignoring those received from other directions.
• Frequency Assignment – Indicates the frequency on which that channel
broadcasts. This number does not necessarily correspond to the channel
number.
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Commonly Used Terms
• Gain – An increase in signal strength, which indicates how much more signal
it delivers than a single element antenna under the same conditions.
• Multicasting – A digital channel can use all of its bandwidth to broadcast
either one station in high definition (HD), or multicast up to four alternative
standard definition stations in the same bandwidth. The primary channel
shows with a “.1” at the end. If the station multicasts, there would be three
additional channels, with the same primary channel number, but having “.2”,
“.3”, and “.4” at the end. Many digital stations choose to multicast during the
day, and then will switch to an HD feed for primetime.
• Multipath – Occurs when the signal from the broadcast station reaches the
antenna at varying times. This often happens when the antenna receives the
signal sent directly from the station, but has another object reflecting the
signal back to the antenna.
• OTA – An abbreviation used that refers to over-the-air channels.
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Commonly Used Terms
• Propagation Type – Classifies antennas based on the direction from which they can receive
off-air signals.
• Polar Plot – A graph that identifies the antenna’s
characteristics such as beamwidth or directivity.
The two polar plots shown here
illustrate the beamwidth and directivity of
a directional antenna, or one that picks up channels
only from one direction, and a bi-directional antenna, or one that picks up channels from
two directions.
• Transmit Towers – Used by the TV station to broadcast the TV signal
• UHF – Ultra-high frequency channels are those from channels 14 through 69, whose
frequencies are located in the UHF band. Digital off-air channels are usually found in this
range.
• VHF – Very-high frequency channels are those from channels 2 through 13, whose
frequencies are located in the VHF band. VHF is sometimes broken into two segments: low
VHF (ch 2-6), and high VHF (ch 7-13).
57
Helpful Links
• www.antennaweb.org – Use this website to look up recommended
antennas, get information about antenna reception patterns, and answers
to frequently asked questions.
• http://www.winegard.com/offair/index.php – Provides information and
specifications on the antennas listed in this training, as well as answers to
frequently asked questions.
• http://www.fcc.gov/mb/facts/otard.html - Provides information on off air
antennas
• http://www.hdtvprimer.com/ANTENNAS/basics.html - Provides
information on TV broadcasts and commonly used terms and equipment.
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