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Appendix
Aligning Single-Polarized Antennas
Use the installation positions and heights of local and remote antennas to determine their azimuths. Adjust the
pitch angles of the antennas to the horizontal position.
Connect a multimeter to the RSSI port on the ODU at the local end and measure the voltage value V
ODU
RSSI Port
Multimeter
Secure the remote antenna and loosen/tighten the level adjustment screw to move the antenna horizontally.
A. If three signal peaks are tracked, adjust the azimuth of the antenna until the received signal level (RSL) reaches
the peak value at position 2.
B. If two signal peaks are tracked, adjust the azimuth of the antenna until the RSL reaches the middle between
positions 4 and 5. Then, adjust the pitch angle of the antenna using the elevation adjustment screw until the three
signal peaks on the line AA' appear. Finally, adjust the azimuth of the antenna until the RSL reaches the peak value
at position 2.
C. If one signal peak is tracked, adjust the azimuth of the antenna until the RSL reaches the middle between
positions 6 and 7. Then, adjust the pitch angle of the antenna using the elevation adjustment screw until the three
signal peaks on the line AA' appear. Finally, adjust the azimuth of the antenna until the RSL reaches the peak value
at position 2.
Front view of the tracking lines at different
天线不同仰角下扫描路径的正面图
elevation angles of the antenna
6
7
C
4
B
2
1
A
52/53 >>
Elevation adjustment
screw
Level adjustment screw
RSL values of each line
各路径信号值
6
7
C'
C
C'
5
4
5
B'
B'
B
3
A'
2
3
1
A'
A
Loosen/tighten the elevation adjustment screw to move the local antenna vertically. Adjust the pitch angle until the RSL
reaches the peak within the tracked range.
Repeat Steps 3 to 4 to ensure that three signal peaks are tracked in horizontal and vertical directions. When the local
.
BNC
RSL reaches the maximum peak value, secure the local antenna.
Adjust the remote antenna to ensure that the RSL at the local end and the RSL at the remote end reach the peak value.
Tighten all screws on both antennas after the alignment is complete.
If the radio link is configured in 1+1 protection mode and one antenna is used at each end, power off the standby ODUs
at both ends before aligning the antennas. After the antennas are aligned, power on the standby ODUs at both ends.
If the radio link is configured in 1+1 SD mode, align the antennas in the following sequence:
1. Power on the main ODUs at both ends. Ensure that they are powered on during the alignment.
2. Power off the standby ODUs at both ends. Then, align the main antennas at both ends.
3. Power on the standby ODU at the local end. Retain the position of the main antenna at the remote end, and adjust
the diversity antenna at the local end.
4. Power on the standby ODU at the remote end. Retain the position of the main antenna at the local end, and adjust
the diversity antenna at the remote end.
If the radio link is configured in 1+1 FD mode and two antennas are used at each end, align the antenna in the following
sequence:
1. Power on the main ODUs, power off the standby ODUs, and align the main antennas at both ends.
2. Power off the main ODUs, power on the standby ODUs, and align the diversity antennas at both ends.
Aligning Dual-Polarized Antennas
In these steps, ODUs at both ends are installed separately from antennas. If ODUs at both ends need to be installed directly on
antennas, the action of adjusting the feed boom needs to be changed to the action of adjusting the OMT.
Power off the vertically-polarized ODU and power on the horizontally-polarized ODU at both ends of a radio link.
This ensures that the antennas at both ends transmit horizontally-polarized signals.
Adjust the azimuth and pitch angle of the antennas at both ends by referring to the description in "Aligning Single-
Polarized Antennas." Ensure that the main lobes of the horizontally-polarized signals are aligned.
Use a multimeter to measure the RSL (P1) on the RSSI port of the horizontally-polarized ODU at the local end.
3
Power on the vertically-polarized ODU at the local end. Use a multimeter to measure the RSL on the RSSI port of
4
the vertically-polarized ODU. Release the feed holders and turn the feed gently until the RSL reaches the minimum
value (P2). The calculated XPD1 (XPD1 = P1 - P2) cannot be less than 24 dB. Make a note of the current angle
(D1) of the feed.
Power off the horizontally-polarized ODU and power on the vertically-polarized ODU at both ends of the radio link.
5
Adjust the azimuth and pitch angle of the antennas by referring to the description in "Aligning Single-Polarized
Antennas." Ensure that the main lobes of the vertically-polarized signals are aligned.
See Steps 3 and 4 to ensure that the calculated XPD2 (XPD2 = P3 - P4) is greater than or equal to 24 dB. Make a
6
note of the current angle (D2) of the feed.
Repeat Steps 1 to 6 to adjust the feed gently (ranging from D1 to D2), and ensure that XPD1 and XPD2 are greater
7
7
than or equal to 24 dB.
8
Tighten all screws on both antennas after the alignment is complete.
22
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