User's Manual

16
4 Site Planning
4.1 Site Selection Criteria
The following are guidelines for selecting the installation location of the OS-Gemini ODU and
IDU.
4.1.1 ODU Site Selection
When selecting a site for the ODU the following should be taken into consideration:
• That it is not possible for people to stand or walk inadvertently in front of the antenna.
• Height and location to achieve the best radio path
• Height in relation to other objects with regard to lightning strikes
• Protection from the elements
• Aesthetics and planning permission issues
• Distance from IDU and connected equipment (Maximum cable run ODU to connected equip-
ment is 100m)
• Distance from the IDU to the ODU (Maximum cable run IDU to ODU is 60m)
4.1.2 IDU Site Selection
When selecting a site for the IDU the following should be taken into consideration:
• Availability of a mains supply
• Accessibility for viewing status indicators (See section 1.3.2 “The Indoor Unit (IDU)” and
section 7 “Fault Finding”
• Distance from ODU and connected equipment (Maximum cable run ODU to connected equip-
ment is 100m)
• Distance from the ODU to the IDU (Maximum cable run ODU to IDU is 60m)
4.2 Path Loss Considerations
The path loss is the amount of attenuation the radio signal undergoes between the two ends of the
link. The path loss is the sum of the attenuation of the path if there were no obstacles in the way
(Free Space Path Loss), the attenuation caused by obstacles (Excess Path Loss) and a margin to
allow for possible fading of the radio signal (Fade Margin).
L
Free Space
+ L
Excess
+ L
Fade
< L
Capability
(1)
where
L
Free Space
= Free Space Path Loss dB
L
Excess
= Excess Path Loss dB
L
Fade
= Fade Margin Required dB
L
Capability
= Equipment Capability dB