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UHF/VHF/FM ANTENNA'S |
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BASIC TV ANTENNA TYPES
TV antennas can be grouped
in four major functional categories: VHF/FM,
UHF, UHF/VHF/FM, and FM only combinations.
Sometimes called also broadband antenna's
VHF and FM Antennas LIKE
CM
Crossfire
Most VHF (Very High
Frequency) antennas are engineered to
receive TV channels 2 through 13. They also
will receive the FM radio band, which is
located between TV channels 6 and 7. FM only
antennas are available also below. Channels
2 through 6 are known as the low band.
Channels 7 through 13 are referred to as the
high band. Some VHF antennas are designed to
receive only one band, either the low or
high band. Antennas designed to receive both
the low band and the high band are called
VHF/FM broad-band antennas.
TV channel 1 "disappeared"
in the early days of TV because of a change
in frequency assignments by the Federal
Communications Commission (FCC). A
reshuffling of FM, Amateur, and other bands
removed TV from the frequencies previously
reserved for TV channel 1. Because the other
12 TV channels were already numbered 2
through 13, the channel 1 designation simply
was dropped.
UHF Antennas LIKE CHANNEL
MASTER
8221
UHF (Ultra High Frequency)
antennas are designed to receive TV channels
14 through 69, the UHF TV band. (Most of
the New off air HDTV channels will be on UHF
band) The UHF TV band originally
extended from channel 14 to channel 83.
However, the FCC now has reassigned channels
70 through 83 (also known as the translator
band) to mobile communications use. Although
there still are many antennas capable of
receiving all 82 channels, the translator
band (former TV channels 70-83) is useless
to the TV viewer. UHF TV antennas come in a
wider variety of shapes and sizes than
VHF/FM antennas. The wider variety of UHF
designs (Figure 1-3) is possible because
they don't require the long elements that
VHF/FM antennas do.
Combination UHF/VHF/FM
Antennas
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ATSC Standards (PDF) |
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UHF Antenna's |
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HOW TO SELECT THE RIGHT ANTENNA
There are many bands and
hundreds of TV antenna models available.
However, choosing the right one is
relatively easy if you are aware of a few
basic reception and TV antenna
characteristics.
First, "good reception,"
or production of a snow-free color TV
picture, requires a signal level of about
1000 microvolts (pV) = 1 millivolt (mV). To
deliver this signal level to the receive,
the antenna requires a certain antenna gain.
The amount of gain required is dependent on
the distance between the station's
transmitting antenna and the receiving
antenna. The required type of antenna
therefore depends on the channels to be
received and the distance and direction of
the customer's home from the transmitting
antennas. These facts are readily available
for any area but be sure your information is
accurate and complete. Call a local TV
station if you have questions. Most TV
stations are willing to help TV antenna
installers because they also benefit from
the improved reception to the station's
viewers.
Be sure to discuss with
your customers the number and types of
channels that are receivable. This may sound
basic, but your customers may not understand
the difference between VHF/FM and UHF. They
also may not be aware that with the right
equipment they may be able to receive
out-of-Town channels, some of which may
carry sports programs that are locally
blacked out. The most important points to
remember when selecting an antenna are its
gain, sensitivity classification,
directivity, and front-to-back ratio.
Gain
The gain of an antenna
indicates the relative strength of signal it
can deliver to a receiver. Most
manufacturers list the gain of their
antennas in decibels (abbreviated "dB"). The
higher the antenna gain, the stronger the
signal at the antenna output terminals. ln
most cases the larger the antenna, the
higher the gain.
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HD 1080i |
Local Channel UNC Educational |
NASA on UNC |
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