WNI Global Challenger L Series, User Reference And Installation Manual

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2-25 This manual is provided by WNI Global and its confidentiality is preserved. Without the pre-written consent from WNI Global,
anyone may not disclose, extract, cite or publish any part or all parts of this manual. Version No.: V2.0
2.5.2
Site Evaluation Process
The following steps must be completed to perform a successful site evaluation. Each step in the
process is detailed in the following subparagraphs:
•
Ensure RF Safety compliance: Ensure that appropriate warning signs are properly placed and
posted at the equipment site or access entry. For a complete list of warnings, refer the Safety
Precautions listed at the beginning of this manual.
•
Ensure Compliance with Laws, Regulations, Codes, and Agreements: Ensure that any
installation performed as a result of the site evaluation is in full compliance with applicable
federal and local laws, regulations, electrical codes, building codes, and fire codes.
•
Establish Line of Sight between Challenger L Digital Radios: The most critical step in
conducting a site evaluation is confirming clear Line of Sight (LOS) between a near
Challenger L Digital Radio and a far Challenger L Digital Radio. If LOS does not exist,
another location must be used.
Challenger L Radios in a link must have a clear view of each other, or “line of sight”.
Binoculars may be used to evaluate the path from the desired location of the near Radio to
the desired location of the far Radio.
To confirm Line of Sight:
•
Ensure that no obstructions are close to the transmitting/receiving path. Take into
consideration trees, bridges, construction of new buildings, unexpected aerial traffic,
window washing units, etc.
•
Ensure that each ODU can be mounted in the position required to correctly align the ODU
with its link partner.
Challenger L Radios must also have a clear radio line of sight. If a hard object, such as a
mountain ridge or building, is too close to the signal path, it can damage the radio signal or
reduce its strength. This happens even though the obstacle does not obscure the direct, visual
line of sight. The Fresnel zone for a radio beam is an elliptical area immediately surrounding the
visual path. It varies in thickness depending on the length of the signal path and the frequency of
the signal. The necessary clearance for the Fresnel zone can be calculated, and it must be taken
into account when designing a wireless links.
As shown in the picture above, when a hard object protrudes into the signal path within the
Fresnel zone, knife-edge diffraction can deflect part of the signal and cause it to reach the
receiving antenna slightly later than the direct signal. Since these deflected signals are out of
phase with the direct signal, they can reduce its power or cancel it out altogether. If trees or other
'soft' objects protrude into the Fresnel zone, they can attenuate (reduced the strength of) a