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What Is A Yagi Antenna?
The word is the name of one of the Japanese inventors of these directional
antennas. The other inventor's name was Uda so in technical circles
these are Uda-Yagi antennas in honor of the inventor team. The invention
is from the early 1900s.
Yagi antennas focus the transmit and receive power in a single direction.
They are best used for fixed locations such as homes, offices, farms
and remote locations trying to reach far away cell sites. They should
be mounted as high as possible on a tubing or pipe such as used
for outdoor TV antennas. For best results, consider installations
that make the cable as short as possible.
While there is a multitude of directional antenna designs in use
today, the Yagi is the most popular, well known and most seen. Some
people call these "beam" antennas, namely CBers and Amateur Radio
Operators.
How Do These Antennas Achieve So Much "Gain"?
Basically they are directing a major or almost all of their signal
in just one direction instead of dispersing all around a 360 degree
circle. |
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Features:
The YAGI 900 is a rugged
broadband GSM YAGI antenna specifically designed for professional
fixed-wired solutions in the 890-960 MHz band.
The YAGI antenna has been
designed for point-to-point signal transfer.
The YAGI 900 can work upto
33 kms. from the last cell tower.
YAGI antennas are ideal
for remote locations where invariably there is only one GSM base
station in the area.
The antenna has a gain of
12-15 dB, which makes it an excellent choice when using any cellphone,
booster or a FCT unit in poor signal areas.
An all metal-to-metal grounded
construction prolongs the useful life of the antenna and improves
reliability and performance.
The antenna weighs less
than 1 kg and can easily be installed by one person in the field.
The antenna exhibits excellent
wide band response across the entire cellu
lar frequency range.
These rugged antennas are
sturdy enough to withstand winds in excess of 100 Kph. |
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What Is "Gain"?
This is the common term used when measuring decibels (dB) to determine
the effectiveness of an antenna in a given direction or plane. Simply
put, it is the measure of the intensified signal where it is wanted
or needed because antennas cannot create gain. The antenna is designed
to manage the power in the wanted direction and thus reduce it in
unwanted directions. |
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Where Can I Mount The Antenna?
Any vertical or horizontal pipe, roof edge, wall, window sill, balcony
railing or fence post can be used. |
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Where Do I
Point The Antenna?
The front of the antenna has to be directed at the target, the cell
site or repeater tower or other user. It is best to use a map and
compass and knowledge of target location but usually you can locate
the target if it has a signal being sent to you. By simply rotating
your Yagi until best signal is found then centering on the estimated
location, satisfactory results may be had. Slowly rotate the antenna
and stop every 10 degrees. Record signal levels. Note the peak and
decline positions and soon a center can be figured out then tighten
the mounting bolts. Be sure to stand at least a couple of feet away
from the antenna and and to the back or sides. Never in front of
the antenna. Your body can greatly alter signal patterns. |
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ANTENNA HEIGHT/CABLE
LENGTH
The antenna needs to be mounted as high and in the clear as possible.
So good thinking must be utilized when deciding when more height
is needed and how much longer the cable will be. On the other hand,
if excess cable length is present, either remove it or run a long
path to the antenna, never coil or fold up the cable.
At cellular frequencies of operation, cable can be quite lossy.
Signal loss or attenuation happens all along the cable. The rule
is, the shorter the better. |
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