User Manual

User Reference and Installation Manual 3-10
MDS 5800 II
• Select the Grounding Location for both the MDS 5800 II ODU and SDIDU
TM
: The MDS
5800 II must be properly grounded in order to protect it and the structure it is installed on
from lightning damage. This requires
- Grounding all ODUs as specified by supplier
- Grounding all SDIDU
TM
to the rack.
• Confirm the Presence of DC Power for the MDS 5800 II SDIDU
TM
.
• Ensure Building Aesthetics: Ensure that the ODU can be mounted so that it is
aesthetically pleasing to the environment and to the property owner. Aesthetics must be
approved by the property owner and the network engineer.
• Take Site Photographs
• Sketch the Site
3.5.3 Critical System Calculations
3.5.3.1 Received Signal Level (RSL) and Link Budget
The received signal level (RSL) can be estimated using the following formula:
RSL (dBm) = P
TX
+ G
TX ANT
– L
Path
+ G
RX ANT
Where: P
TX
is the transmitter output power (in dBm)
G
TX ANT
is the gain of the transmit antenna (in dB), 23 dBi for ODU’s internal antenna
G
RX ANT
is the gain of the receive antenna (in dB), 23 dBi for ODU’s internal antenna
L
Path
is the Path loss, defined by:
L
P
(dB) = 36.6 + 20log
10
(F*D)
Where: F is the Frequency in MHz (5800 or 5300), D is the Distance of path in miles
This link budget is very important in determining any potential problems during installation. The
expected RSL and measured RSL should be close (+/- 5 to 10 dB)
3.5.3.2 Fade Margin Calculation
The fade margin is the difference between the actual received signal and the MDS 5800 II
Radio’s threshold for the modulation mode selected. The fade margin can be used to determine
availability and should be at least 10 dB.