FibeAir IP-20C/S/E
User Guide
Ceragon Proprietary and Confidential
Page 357 of 597
3 Record the RSL
wanted
and mute the first radio carrier at each end of the
link.
4 Unmute the second (orthogonal) radio carrier which was muted during the
antenna alignment process.
5 Determine the XPI, by either of the following two methods:
Measure the RSL of the second carrier (the “RSL
unwanted
”). To calculate
the XPI, subtract RSL
unwanted
from the RSL
wanted
.
Note:
To measure the second carrier, leave the Voltmeter
connected to the BNC connector. In the Radio Parameters
page of the Web EMS (Figure 17), change the RSL
Connector Source field from PHYS1 to PHYS2 (or vice
versa). The BNC connector will now measure RSL from the
other carrier.
Read the XPI by going to radio view and entering one of the following
commands:
radio [x/x]>modem pm-xpi show interval 15min
radio [x/x]>modem pm-xpi show interval 24hr
6 The XPI should be at least 25dB. If it is not, you should adjust the OMT
assembly on the back of the antenna at one side of the link until you
achieve the highest XPI, which should be no less than 25dB. Adjust the
OMT very slowly in a right-left direction. OMT adjustment requires very
fine movements and it may take several minutes to achieve the best
possible XPI. It is recommended to achieve XPI levels between 25dB and
30dB.
7 Enable all four radio carriers and check the XPI levels of both carriers at
both sides of the link by going to radio view and entering one of the
following commands:
radio [x/x]>modem pm-xpi show interval 15min
radio [x/x]>modem pm-xpi show interval 24hr
All four carriers should have approximately the same XPI value. Do not
adjust the XPI at the remote side of the link, as this may cause the XPI at
the local side of the link to deteriorate.
Note:
In some cases, the XPI might not exceed the required 25dB
minimum due to adverse atmospheric conditions. If you
believe this to be the case, you can leave the configuration at
the lower values, but be sure to monitor the XPI to make
sure it subsequently exceeds 25dB. A normal XPI level in
clear sky conditions is between 25 and 30dB.
14.4.3
Configuring the Radio Carriers for XPIC (CLI)
To configure the radio carriers:
1 Configure the carriers on both ends of the link to the desired frequency
channel. Both carriers must be configured to the same frequency channel.
2 Assign XPIC (CCDP operational mode) support-enabled script to both
RMCs on both ends of the link. Each RMC must be assigned the same script.
See Configuring the Radio (MRMC) Script(s) (CLI).
