User's Manual Part 3
Release8InstallationandConfigurationGuide
Issue2,November2007 Draft5forRegula toryReview 362
IMPORTANT: The received Power Level is shown in dBm and should be
maximized. Jitter should be minimized. However, better/lower jitter should be
favored over better/higher dBm. For example, if coarse alignment gives a BHS
a power level of −75 dBm and a jitter measurement of 5, and further refining
the alignment drops the power level to −78 dBm and the jitter to 2 or 3, the latter
would be better, with the following caveats:
• When the receiving link is operating at 1X, the Jitter scale is 0 to 15 with
desired jitter between 0 and 4.
• When the receiving link is operating at 2X, the Jitter scale is 0 to 15 with
desired jitter between 0 and 9.
NOTE:
For historical reasons, RSSI is also shown and is the unitless
measure of power. The best practice is to use Power Level and
ignore RSSI, which implies more accuracy and precision than is
inherent in its measurement.
3. Fine-adjust the BHS mounting, if needed, to improve Jitter or Power Level.
4. Click the Link Capacity Test tab of the Tools web page in the BHS.
NOTE: Use of this tool is described under Using the Link Capacity Test Tool (All)
on Page 438.
5. Perform several link tests of 10-second duration as follows:
a. Type into the Duration field how long (in seconds) the RF link should be
tested.
b. Leave the Packet Length field (when present) set to the default of 1522
bytes or type into that field the packet length at which you want the test
conducted.
c. Leave the Number of Packets field set to 0 (to flood the link).
d. Click the Start Test button.
e. View the results of the test.
6. If these link tests fail to consistently show 90% or greater efficiency in 1X
operation or 50 to 60% efficiency in 2X, troubleshoot the link, using the data as
follows:
• If the downlink is consistently 90% efficient, but the uplink is only 40%, this
indicates trouble for the BHS transmitting to the BHM. Investigate a possible
source of interference near the BHM.
• If the uplink is consistently 90% efficient, but the downlink is only 40%, this
indicates trouble for the BHM transmitting to the BHS. Investigate a possible
source of interference near the BHS.
If these link tests consistently show 90% or greater efficiency in 1X operation, or
50 to 60% efficiency in 2X operation, in both uplink and downlink, continue this
procedure.
7. Open the Session Status tab in the Home page of the BHM.
NOTE: An example of this page is shown in Figure 136.