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| How
much spacing between antennas is required? |
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Optimum spacing is a minimum of
one wavelength at the lowest frequency of operation. This
can be impractical for certain applications. Good performance
can be achieved with closer spacing depending on the application.
[back] |
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| How
do I properly install a connector? |
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Careful preparation of the coax
and appropriate experience is required for this important
connection in the antenna network. Antenex provides this expertise
at a competitive price. Call us for a quote. [back]
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What is dB, dBi, dBd and dB MEG? |
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dB is a logarithmic function that
is used as reference to define antenna gain. Each 3dB of gain
is an effective doubling of output power. Many times this
figure is expressed with reference to a known standard. Such
is the case with dBi where the gain is referenced to an isotropic
or 0dB source, dBd where the gain is referenced to a dipole
antenna or 2.4dB source and dB-MEG where the gain is referenced
to Mean Effective Radiation. [back] |
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| Where
do I measure from when I trim the antenna whip for a load
coil antenna? |
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Refer to the instructions supplied
with the product. You can also locate our instruction sheets
and trimming information on our website under Technical Resources.
Typically, the measurement is made from the top of the corona
ball to the very bottom of the rod. [back] |
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| How
do I tune a dual band antenna? |
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Antenex dual band antennas are
carefully tuned at the factory. No tuning is necessary. [back]
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| How
far can I communicate with a two watt radio and a 3dB antenna? |
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Each situation is different based
on terrain, environment, receiver sensitivity, etc. Every
3dB of gain from the antenna equates to a virtual doubling
of effective radiated power (ERP). A good rule of thumb is
that for every one watt of ERP, the effective communications
distance is approximately one mile. [back]
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| What
is “E” plane and “H” plane in an antenna pattern? |
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Two components of a signal are
radiated in two planes each at right angle to one another.
They are defined as the electrical component or E-plane, and
the magnetic component or H plane. [back]
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| Can
I get jumper cables made to a custom length? |
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Yes! Antenex has automated cable
processing equipment that enables us to be very competitive
as a source for custom jumpers. Some jumpers with the most
popular lengths and terminations are available from stock.
We can also quote any custom requirement. [back]
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| Which
mounting kit can I use with my Antenex mobile antenna? |
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Most Antenex antennas utilize
the familiar Motorola mounting scheme with the 1-1/8” - 24
thread specification mounted in a ¾” hole. Any one of our
permanent ¾” hole mounts, magnetic mounts or trunk mounts
can be used to mount your antenna. [back]
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| How
do I know if my order has shipped? |
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Please call our customer service
line at 800.323.3757 for order tracking information. [back]
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| What
cable should I use for my antenna installation? |
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Antenex offers a complete selection
of quality coax cables such as RG58U, RG58A/U, RG174, RG316,
Dual shield Teflex coax, heat resistant Teflon coax, RG8X
among others. Recognized suppliers produce these cables to
our exacting specifications. The appropriate cable selection
is determined by application. In a standard application, RG58A/U
is used the most. If you have a high heat environment, a heat
resistant Teflon coax is recommended. [back]
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| What
connectors are available? |
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Antenex can supply antennas with
almost any connector, or even without a connector for OEM
applications. Standard connectors are Type N, BNC, FME, TNC,
SMA, SMB, MCX, and MMCX. Cable size dictates which connectors
may be used on certain antennas. [back]
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| Explain
antenna propagation and the proper grounding planes for the
different types of antennas available. |
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Ground planes are required to
properly impedance match quarter-wave or collinear antennas
launched directly from a conductive surface. The first element
relies on image theory, described as a virtual antenna of
equivalent length and spacing below the ground plane performing
cooperatively with the physical antenna to provide impedance
matching for far field radiation. Half-wave or 5/8-wave radiators
can be stacked vertically to achieve higher gain. A ground
plane defines the proper ground plane dimensions, which is
much larger (in both directions) than the antenna length.
[back] |
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| How
much loss results from each connector installed on the cable? |
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Connector loss is negligible
with respect to the overall cable loss. Some manufacturers
suggest adding 0.1 dB for every 2 connectors within a cable
system for planning purposes. [back]
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| Explain
the theory behind portable antenna design and their length
with respect to operational wavelength. |
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Traditional portable antennas
are generally less efficient, short radiators impedance matched
to the radio circuitry and case. At higher frequencies (shorter
wavelengths) such as 800/1900 MHz, end fed designs can accommodate
true 1/2-wave radiators that are independent of the case and
user, providing efficient dipole radiation characteristics.
[back] |
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| Is
antenna length important to reception? |
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Antenna length is critical to
maximize performance and provide the proper radiation characteristics.
The length of an antenna has an important influence on characteristics
such as directivity and bandwidth. [back]
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| Will
dual band antennas work as well as single band or do they
match the antennas in the middle of the frequency range? |
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Properly designed dual band antennas
will provide a good impedance match over both bands. Dual
bands are designed for resonance and proper phasing in each
band and not centered between the bands. However, compromises
must be made with respect to the radiation efficiencies in
each band. Single band antennas are optimized for single band
performance and typically perform better than dual band antennas
in their respective band of operation. [back]
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| Why
is gain important? |
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Gain is an important measure
because certain gain figures are better suited to particular
usage environments. For strictly urban use, a unity gain antenna
is ideal. Because a unity gain antenna send the maximum signal
above the horizon at a high angle, it is excellent for areas
where there are tall buildings and for mountains as well.
For people who live in suburban or rural areas, 3 dBd gain
is recommended. The 3dBd gain antenna concentrates the maximum
amount of signal at the horizon while maintaining a good high-angle
signal. If you are a cellular user, there is not need to buy
an antenna stronger than 3 dBd gain as the USA cellular infrastructure
is designed for optimum performance using 3 dBd gain antennas.If
you are using a Land Mobile Radio (LMR) system and are in
a rural area, a 5dBd gain antenna is suggested as this will
help to provide the maximum amount of signal at the horizon
with very little high-angle signal. Finally, the gain is a
practical value which describes the capability of an antenna
to concentrate energy in a particular direction of space.
[back] |
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| With
my low-band antenna mounted on the roof of my car I had great
VSWR. I moved it to a trunk bracket and now it doesn't tune
properly. Why? |
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The antenna is responding to
the ground plane size and shape in the immediate field of
the whip. Ground plane effects are significant at low frequencies,
because a quarter-wave is fairly long for low-band frequencies.
[back] |
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| I’m
using one of your rubber duck antennas on our electronics
box. Our system hasn’t been working right. When I tested the
antenna VSWR I found it was very high. What’s wrong with your
antenna? |
|
We need to understand what kind
of rubber duck you are using. Most require a good ground plane
for good performance. If your box is made of plastic, fiberglass,
or other non-metallic materials, there may not be enough ground
plane. If your box is metal, but is small in wavelengths,
there may still be inadequate ground plane. One solution may
be to use a half-wave antenna if your application will allow
the additional height. Half-waves work independent of a ground
plane. [back] |
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What type of antenna should I use for Point-to-Point data
transmission? |
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Directional antennas should be
used for point-to-point transmission. The type of directional
antenna depends upon the power output, cable type and length,
height, distance, data rate and terrain. [back]
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What polarization should I use? |
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Most Point-to-Multipoint WLAN
systems use vertical polarization. This allows the use of
inexpensive vertical omni directional antennas. Point-to-Point
systems may use either vertical or horizontal polarization
as long the same polarization is used at each end. Horizontal
polarization may perform slightly better when transmitting
through a forested area, otherwise there is very little difference
in propagation effects. [back]
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Why is a wavelength (or fraction of) in coax cable physically
shorter than what I calculate from the formula for wavelength? |
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The formula you used to calculate
the wavelength was probably meant for calculating a "free
space" (air) wavelength. In fact, RF energy moves more
slowly in a transmission line than it does in air because
the materials used in cable slow it down. Therefore, a wavelength
in cable takes up less length. The appropriate formula for
the calculation of the guided wavelength is:  where
is the dielectric constant of the material (1 for the air,
and >1 for other types of material). This value increases
as a function of the frequency. [back]
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Can an antenna be cut to any length or does it have to be
kept at its original length? |
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The antenna cannot be cut and
is specifically designed to resonate at the design frequencies
with the proper phasing between the elements. The coupling
box is also designed to match the antenna to the Cellular/PCS
frequencies, which is critical to maintaining the antenna
system performance. [back]
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Does slightly bending the whip reduce antenna performance? |
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Slight bends should not affect
the antenna significantly. [back]
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Can I cut the coaxial cable? And if not, how do I store excess
cable? |
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Yes, the coaxial cable can be
cut without degrading performance. Excess cable can be stored
in any manner as along as the coiled cable does not exceed
the specified bend radius. [back]
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If I use existing coax from a damaged, currently installed
antenna with a new coupling box and whip, are their any concerns? |
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As long as the cable and connectors
are in good condition, they should not need replacing. [back]
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What colors are the Phantoms antennas available in? |
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The Phantom antenna
comes in white and black. [back]
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Can the Phantom antennas be painted? |
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Yes you can paint
the Phantom antenna you must use non-metallic paint. [back]
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What are the bandwidths of the VHF antennas? |
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The Tx band width
of the Phantom antenna is 1.5 MHz. [back]
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What type of connector is used on the permanent mount Phantom? |
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This is a NMO mountable
antenna. [back] |
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Where can I mount a No Ground plane Phantom antenna? |
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To any non-metallic
surface. [back] |
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Does the GPSU15M come with a cable assembly? |
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No this antenna
does not come with a cable assembly. [back]
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What type of cable should I use with the NMO mountable GPS
antenna? |
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The recommended
cable is LMR 195 Cable the cable has a very low loss characteristics.
[back] |
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Is a ground plane required for a GPS antenna? |
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No the GPS antennas
do not require ground planes. [back]
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Are Antenex GPS antennas active or passive? |
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These are active
antennas. [back] |
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Are there antennas available for non-metallic surfaces? |
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“ No Ground Plane”
Yes these antennas are available in no ground plane. [back]
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Can I add a spring after I install an antenna? |
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Yes you can add
a spring after ordering this antenna but it is difficult to
tune with out a network analyzer. [back]
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What is the difference between the Gains? |
|
Unity (0 dBd), 3
and 5 dBd designs differ by the number of elements incorporated
to achieve increased gain. Gain increase is achievable by
stacking multiple elements in a collinear manner to compress
the vertical plane pattern and direct more energy toward the
cell site. [back] |
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What is the benefit of gold plated pushpins? |
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The benefit is that
gold plate will not rust or corrode. [back]
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What is the benefit of tuning the antenna on the car? |
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The benefit of tuning
the antenna on your car is that the antenna will be tuned
to application in which it is in, this will give you the best
results. [back] |
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Can or how do I tune these antennas? |
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No, you cannot tune
these antennas. [back]
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Are these antennas available in a no ground plane version? |
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No, these antenna
are not available in a no ground plane version. [back]
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What are the benefits of tuning the ferrule? |
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This benefit is
that you do not have to cut the rod. [back]
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Why is a gold plated brass contact used? |
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This will give optimal
performance and a good contact over a long period of time.
[back] |
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What are the benefits of the stand up grommet? |
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The benefit is that
the antenna’s grommet will hold its form better. The antenna
will stay vertical. [back]
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Are these antennas dBd, dBi, or dB? |
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All quarter wave
antennas are Unity gain unless other wise noted. [back]
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Is a ground plane required for this antenna? |
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No, there is no
ground plane needed for this antenna. [back]
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Are shock springs available for this antenna? |
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These antennas automatically
come for this antenna. [back]
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How does the elevated feed antennas work? |
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The way these antennas’s
work is that the whole antenna is elevated from the base,
allowing the antenna to be elevated. [back]
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Can you add a shock spring to this antenna? |
|
Yes you may add
a spring to these antennas. [back]
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Are there higher gain Discadoo antennas available? |
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No, there is not.
[back] |
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Are there VHF and UHF Discadoo available? |
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No, there is not.
[back] |
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Are Bi-directional amplifiers available? |
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Yes they are please
refer to page 28 in the catalog. [back]
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What is the connector on this antenna? |
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These antennas come
standard with a TNC connector but you can ask for different
connectors. [back] |
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Can these antennas be painted? |
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Yes you can mount
this antenna at a angle. [back]
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Can I mount the Heavy Duty Omni Fiberglass antenna upside-down? |
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Yes you can mount
the antenna up side down. [back]
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Can I tune this antenna? |
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No you cannot tune
this antenna this must be done from the factory. [back]
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What type of connector comes on this antenna? |
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This antenna comes
with a type “N” connector. [back]
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Can I mount this antenna on an angle? |
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Yes you can mount
this antenna at a angle. [back]
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How do I tune this antenna? |
|
You cannot tune
this antenna this must be tuned at the factory. [back]
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Do mounting kits come with antenna? |
|
No, mounting kits
do not come with this antenna; the most common mounting kit
is the FM2. [back] |
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Should I use a Lightning Arrestor? |
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A lightning arrestor
will protect your radio unit - installation is advised. [back]
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Can I mount the Fiberglass antenna to a Metal roof? |
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Yes but you should
use a RF choke clamp. [back]
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Do I need a ground plane for this antenna? |
|
No, you do not need
a ground plane for this antenna. [back]
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What type on connector comes with the Fiberglass antenna? |
|
This antenna comes
standard with a type “N” female connector. [back]
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Can I stack the Yagi antennas? |
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Yes, Yagi antennas
can be stacked. [back]
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How do I mount a Yagi antenna? |
|
The antenna must
be mounted to a vertical mast with the drain holes pointed
down. [back] |
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What about tuning? |
|
There is no need
to tune this antenna, the design exhibits broad bandwidth
and gain performance with respect to frequency. [back]
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Do mounting kits come with antenna? |
|
Yes! A colid cast
aluminum mounting kit with stainless steel hardware is included.
[back] |
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How does the Lightning Arrestor work? |
|
When lightning energy
strikes the antenna, the energy shorts the gas tube which
directs the energy to ground thus protecting valuable radio
equipment. [back] |
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Will I have to buy a new Lightning Arrestor after it gets
struck by lightning? |
|
No you will not
have to buy a new lightning arrestor you will need to buy
a replacement gas tube. [back]
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What is the frequency range of the 2.4GHz model? |
|
The range is up
to 4GHz. [back] |
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Schaumburg, Illinois 60173 