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131908/2

C+A

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components that were used as well as the mast height should be noted at this time.
You should also create a simple drawing of the antenna installation, including
structural supports and ground system relative to the layout of the house, generally
drawn on the back of the work order.

Testing for Signal Strength with a Site Survey Rig

The first step of the site survey is to verify where the best signal reception is
accommodated on the customer’s home.  Most installers are provided with a test kit that
includes a lightweight, telescoping, fiberglass push-up mast with attached antenna.
The antenna gain should be specified by the system engineering staff.

The most satisfactory method to ensure clear and adequate system performance is to
achieve a signal-to-noise (S/N) ratio of at least 30 dB.  This ratio is measured using a
signal level meter/QAM analyzer and may be calculated for California Amplifier
transceivers with reasonable accuracy, using the formula below:

S/N = 25 + Transceiver IF Output Level (in dBmv)

TECHNICAL TIP

: When reading signal levels, an installer must always be aware of

physical factors that can affect system performance.  Microwave signals are highly
susceptible to absorption by trees and other foliage.  A wireless antenna thus cannot
view the transmitter from behind a tree. Distant trees can also cause reception
problems.  While they may not be visible to an installer, they may still lie in the
transmission path.  

Signal fluctuations exceeding 2 dB during a survey may be an

indication of distant foliage problems

.

Foliage from winter to summer will affect the strength of the received signal.  Trees that
are barren in the winter present very little signal attenuation.  In the summer when the
trees are full of foliage the attenuation can be as high as 10 dB per tree in the line sight
path.  NEVER attempt to receive a signal through a barren or partially barren tree.

Of course, hills and large buildings can completely obscure or deflect microwave signs.
Still other interesting problems can result when the microwave beam grazes the top of
a hill or building, partially deflecting the beam, or when reflective surfaces (bodies of
water, buildings, etc.) cause multiple signal paths from the transmitter into the receive
antenna, a problem known as “multi-path” can occur.

Never use a signal received from a reflection as its reception characteristics can change
drastically over time.  Only line-of-sight signals should be used.

Summary of Contents for 520004-1

Page 1: ...known hazards damage and or unacceptable performance The information contained in this applications note is intended to assist the operator in developing a set of installation guidelines and operating...

Page 2: ...lowing table summarizes the minimum distance required to satisfy these requirements Limits Minimum P N Integrated Planar 17 dBi Standalone when used with 24 dBi 520005 1 N A 26 in 66 cm 520004 1 N A 4...

Page 3: ...wed by a short roof or chimney mount When higher gain or foliage clearance is needed then a tree mount or mast mount should be considered The following mounts are described and their general applicati...

Page 4: ...plication of brick type chimneys a dual band strap mount is best The proper strap will securely fasten the mounting bracket and antenna For wood over metal construction chimney a version of the wall m...

Page 5: ...plicable specifications and drawings of the system operator This requirement includes the choice of antennas the weatherproofing of all connections all penetrations into the building and all grounding...

Page 6: ...an affect system performance Microwave signals are highly susceptible to absorption by trees and other foliage A wireless antenna thus cannot view the transmitter from behind a tree Distant trees can...

Page 7: ...ETY NOTE Aluminum ladders are not to be used for field installation or repair service Only ladders that have fiberglass rails may be used because of the possibility of contact with electrical wires or...

Page 8: ...the scope of these instructions to recommend a method Please check with the system operator s installation guidelines for recommended procedures 6 Once inside the customer premises the cable must be r...

Page 9: ...131908 2 C A 9 Transceiver Planar Array Antenna Cable Modem...

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