Television Antenna FAQs
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Q: How can I view Over The
Air (OTA) Digital and HDTV
broadcasts? |
A: There are currently 3 ways to
view your local stations
(digital and digital HD):
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An over the Air only digital
receiver that will tune in
only the local channels.
These can be purchased at
any electronics chain for
about $100-$399. One
advantage to this, is there
will be no monthly fees.
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An HDTV with a built in OTA
tuner. You will find that
these "integrated" HDTVs
will run $300-$600 more than
a "HDTV ready" display.
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An HD satellite tuner. Both
Dish Network and Direct TV
offer HDTV satellite
receivers with the over the
air tuner built into the
same unit. The advantage of
using this method is that
there is no need to utilize
separate equipment to
receive premium HD networks
like HBO HD and ShowTime HD.
Also, the local and
satellite channels can both
be integrated into the
program guide, to make it
seamless for the viewer when
switching between local and
satellite. You will need an
over the air antenna (like
the ones we sell) as well as
the dish connected to the
receiver. These receivers
can cost anywhere from $399-
$599 although with specials
& promotions it is often
possible to find them for
much less.
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Q: Are all Digital Channels
on UHF? |
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A: No, but currently, 91% of
broadcasting DTV stations are on
UHF. A few cities, such as
Chicago and Las Vegas have DTV
stations on VHF as well as UHF.
While Many DTV stations are now
occupying UHF broadcast
channels, the plan may allow
some broadcasters to move back
to their original VHF or UHF TV
channels once the transition to
DTV is complete. However, this
may not occur for another 10-15
years. |
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Q: How is reception in
distant or "fringe" areas? Will
I get a fuzzy picture? |
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A: When it comes to digital
television, it's an "all or
nothing at all" proposition.
Once the signal is acquired, a
steady stream of data assures
you'll get a perfect picture and
great audio. If that bit stream
is interrupted, however, there
will be nothing - just a blank
screen. In areas with lots of
buildings or obstacles,
multi-path distortion can cause
a "cliff effect" to kick in. The
fix is to use a higher-gain
antenna assuming the multi-path
can be tamed. Work is being done
to determine the optimal designs
for improving error correction
in set-top receivers. |
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Q: How do analog TV
broadcasts and DTV compare to
each other? |
A: There are some similarities.
Both use VHF and UHF broadcast
frequencies. While analog and
digital television broadcasts
have a modulated carrier wave,
the way that signal is modulated
is entirely different. Analog TV
uses an amplitude-modulated (AM)
signal for pictures and
frequency modulation (FM) for
audio, while DTV signals use
digital "packets", to transmit
pictures and audio.
The modulation system currently
being used for DTV in the United
States is Eight Level Vestigial
Sideband (8VSB). As Terrestrial
Digital / HDTV broadcasts become
more prominent, UHF antennas
will play a larger role because
the majority of the HDTV/Digital
channel allocations will be in
the UHF frequency band. |
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Q: What cities have digital
VHF Stations? |
A: One potential problem with
re-using low VHF (2-6) and high
VHF (7-13) TV channels for DTV
is the possibility of
interference from other signals
during certain times of the
year. "Skip" may bring in
distant broadcasts on the same
channel and create interference.
The physical size of low VHF and
high VHF antennas is much larger
than that of a UHF antenna.
DTV broadcasts use the same
channels (frequencies) as
regular analog television. |
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Q: What is a Yagi? |
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A: The Yagi antenna is credited
to Hidetsugu Yagi (although not
the original inventor), A
Japanese physicist. The Yagi was
designed to improve the gain of
the antenna concentrated in one
direction. The directivity is
accomplished with added elements
called directors and reflectors.
The Yagi has high Gain, is very
directional, and has narrow
bandwidth. In simple
unidirectional antennas like the
Yagi, frequency bandwidth is
inversely proportional to
antenna gain. One way to
increase the frequency bandwidth
of a simple antenna like a Yagi,
is to increase the diameter of
the antenna conductors. The
greater the conductor diameter,
the wider the band with
increased conductor diameter
also has a second benefit, it
increases the physical strength
of the antennas. |
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Q: What is the difference
between UHF and VHF antennas? |
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A: The most obvious difference
between VHF and UHF antennas is
the size. A half wave dipole for
channel 2 will be 10 times
longer than for channel 28. This
means that a much more elaborate
UHF antenna can be constructed
without the antenna becoming
physically unmanageable. With
more elements added to the UHF
antenna, higher gain and
directivity can be obtained. |
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Q: What is the Bow tie
Antenna? |
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A: A bow tie antenna is another
name for a UHF fan dipole
antenna. By using triangular
elements instead of rods, the
bandwidth is greatly increased,
to cover the entire UHF band.
Additionally, the mesh reflector
of the bowtie is more efficient
than the rod reflector as it is
lower in weight and has less
wind resistance. |
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Q: What is the Corner
reflector Yagi? |
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A: The corner reflector is a
popular UHF reflector, that has
a very high front to back pickup
ratio; for reducing reception
from the backside. This is
particularly important if you
don't want interference from
stations to the rear of the
antenna. The driven element is
placed at the center of the
corner angle that affects the
power gain, directivity and
impedance. Combined with Yagi
type directors this increases
the gain and directivity of UHF
antennas over the entire UHF
band. |
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Q: My wife won't let me put
one of these things on my roof.
Can I install an antenna in my
attic? |
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Yes you can, but keep this in
mind. One layer of asphalt
shingles + roof felt + ¾"
plywood roof deck = 50%
reduction in signal strength.
Plus if you have metal or
aluminum backed insulation in
the walls or under the roof the
signal will be most likely
blocked. You'll have to remove
the insulation or install the
antenna in a different place.
Although the antenna is inside,
you'll still need to make sure
that the narrow end points
toward the transmitter of the TV
station. |
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Q: My Homeowners association
prohibits antennas on the roof,
what can I do? |
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A: Show them the Federal law
concerning antennas, homeowners
and their rights. In 1996, The
FCC affirmed the rights of
homeowners to place antennas on
property they own or control.*
Check out the FCC ruling here:
http://www.fcc.gov/mb/facts/otard.html.
The law basically states that
homeowner association covenants
cannot prevent you from
installing antennas or dishes.
The rule "prohibits restrictions
that impair the installation,
maintenance or use of antennas
used to receive video
programming." *Masts higher than
12 feet above the roofline may
be subject to local permitting
requirements. |
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Q: How far can I be from the
transmitters and still get a
good signal? |
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A: Getting reliable UHF DTV
reception beyond the curvature
of the earth (approximately 70
miles) is difficult. The good
news is that terrain has a major
impact on reception. Going over
water is about the best it gets,
since water is generally flat
and has positive impacts on
temperature for sending the
signal along. Still, beyond 70
miles, unless you can get direct
line-of-sight to the
transmitters, the number of
things that could impact
reception negatively are
numerous. Just keep this in mind
going in. Accept that what you
want may not be possible. |
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Q: I have read ads for an
antenna that can pick up
stations 200 miles away. Is this
possible? |
A: Under extremely rare
circumstances, a television
antenna could possibly pick up
stations 200 miles away.
However, rarely is, an antenna
going to get terrestrial
television broadcasts over such
a distance.
Theoretically, it would be
possible if you lived on top of
a mountain and the broadcast
towers were also on a mountain.
At normal elevations, however,
the curvature of the earth
pretty much limits effectiveness
to about 70 miles for UHF band
signals. Low VHF band (2-6) can
bounce further than this, but
currently only about 7% of
digital TV channels are on the
VHF band. Most Digital TV
channels are on the UHF band -
which is line-of-sight
transmission. |
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Q: What about "HDTV" antennas
they sell at the electronic
chain stores, won't these work? |
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A: Maybe, but often times they
are no better than a coat
hanger. Very few of the antennas
sold in this electronic chain
stores have much success with
digital reception. They usually
have poor gain on the
frequencies where digital
broadcasts occur and have a
difficult time with multi path
distortion. Most utilize low
grade amplifiers that introduces
noise on the line or are shaped
to be aesthetically pleasing,
but contrary to the principals
of digital TV reception. |
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