User's Manual

Chapter 5. The PacketWave AIM
5–12
10004880 Rev. D1
Aligning the Antenna
When the Alignment Window is displayed (Figure 5-10), the ODU will begin slowly beep-
ing. The beep is an audio indication of the strength of the signal received from the base
station. As reception gets stronger (within the range from -50dBm to -100dBm), beeping
increase in pitch and frequency, becoming a continuous tone when the signal is optimal.
To align the antenna, perform the steps in this section.
18. For most situations, verify that Quick scan in the Alignment window is checked as
shown in Figure 5-10. This will cause the PacketWave 200 to scan through frequen-
cies and transmission variables such as gain more quickly than it would otherwise
do. Generally, Quick scan should be unchecked only when there are multiple fre-
quencies (AFS) or the SU will be connected to more than one BSU/WSS for backup.
19. To use the audio signal for antenna alignment:
a. Adjust the position of the ODU for the highest pitch and frequency of the
beeping, ideally finding a position which results in a continuous tone. Secure
the ODU in that position.
b. When the ODU receives a continuously strong signal for one minute (specifi-
cally, when the signal-to-noise ratio is higher than 16 dB and the signal
strength is greater than -88 dBm without varying by more than 2 dB for one
minute), the PacketWave 200 will become operational with an audio tone
similar to a telephone ringing.
20. To use the AIM graphs for antenna alignment:
a. While viewing the graph shown in Figure 5-10, move the antenna to maximize
the signal strength as shown on the graph. Values greater than -82 dBm will
work in 16QAM. Values greater than -89 dBm will work in QPSK.
If the signal does not move up from the bottom of the Local Signal Strength
graph (i.e., shows -100 dBm), do the following:
• Verify that the frequency and BSU ID were correctly configured.
• If the link has line-of-sight between the antennas, you should know the
general direction to align the antenna. Start in that direction. Move the
antenna every few seconds until the Local Signal Strength line rises at
lease once. Once it rises, slow the movement of the antenna. If the Sig-
nal Indicator line has not risen after 2 to 3 minutes, it is best to click the
Previous and then the Next buttons to reset sequence.
• If the installation is not line-of-sight, either search for a first synchroni-
zation (as indicated by the rise of the Signal Indicator line) or just pick
a direction to align the antenna.
b. Once the Local Signal Strength value is maximized, click on the View SNR
button to display the full window as shown in Figure 5-11. SNR (signal-to-
noise ratio) values in the red area are not good; values in the yellow area are
acceptable; values in the green area are best. (However, the unit can operate
reliably to an SNR level of 12 dB in QPSK.)
c. Adjust the antenna again until Local Signal Strength and SNR are maximized.