Antenna Installation Questions
- How can I pick up Over The Air (OTA) Digital and HDTV broadcasts?
- There are currently 3 ways to pick up your local stations:
- 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
$299-$399. One advantage to this, is there will be no monthly fees.
- 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.
- 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.
- Are all Digital Channels on UHF?
- 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.
- How about reception in distant or "fringe" areas? Will I get a fuzzy picture
- 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.
- How do analog TV broadcasts and DTV compare to each other?
- 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.
- What cities have digital VHF Stations?
- 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.
- What is a Yagi?
- 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.
- What is the difference between UHF and VHF antennas?
- 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.
- What is the Bowtie Antenna?
- 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.
- What is the Corner reflector Yagi?
- 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.
- My wife won't let me put one of these things on my roof. Can I install an antenna in my Attic?
- 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.
- My Homeowners association prohibits antennas on the roof, what can I do?
- 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."
- How far can I be from the transmitters and still get a good signal?
- 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 is numerous. Just keep
these in mind going in to the project. Accept that what you want may
not be possible.
- I have read ads for an antenna that can pick up stations 200 miles away. Is this possible?
- 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.
- What about "HDTV" antennas they sell at the electronic chain stores, won't these work?
- Some
will, but very few of the antennas sold in 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
introduce noise on the line or are shaped to be aesthetically pleasing,
but contrary to the principals of digital TV reception.
- My channels display as 2.1, 5.1, 7.1 etc. So I need a VHF antenna right?
- No,
what you are looking at on your display is likely a re-map. If your
analog station is broadcasting on a frequency assignment of say 2 then
the digital broadcast will must be on a separate frequency as two TV
stations cannot broadcast on the same frequency at the same time. For
example the analog assignment for the KCBS in Los Angeles is Ch 2 and
the digital broadcast will likely show up on a tuner as 2.1, but the
digital frequency is actually 60. Remember, the vast majority of
digital broadcasts are on the UHF band.
- I bought an HDTV set and my picture still looks the same even after I
bought your antenna, and sometimes I see snow or fuzz. I know it's not
the TV's fault because it was the top of the line. The salesman told me
everything I needed is built into the TV.
- Many
people (and a good number of TV salesmen) are not aware that that their
HD ready sets do not have a digital tuner built in. If your owners
manual or literature does not specifically state that an ATSC or
digital tuner is included, then you will need to get an external set
top box (ATSC HD tuner) which will run about $200-$350. The majority of
large screen TVs purchased after January 2006 have a built in tuner.
