Parameters
| ID | Name | Meaning |
|---|---|---|
| 1 | Site No. | Number of the site where the faulty board or module is located Value range: 0-2047 |
| 2 | Board Type | Number of the type which the faulty board belongs to. C7:P-CDU C9:D-CDU |
| 3 | Board No. | Number of the fault board 0:CDU 0 1:CDU 1 |
| 4 | PassNo | Number of the passage where the faulty board is located. |
| 5 | SubLink No. | Alarm sub-category number 255: None |
| 6 | Cell Index | Index of the cell where the board or module is located 0-2047: Cell index of the faulty cell in the data configuration 65535: None |
| 7 | Site Type | Type of the site where the faulty board is located. 3:BTS30; 5:BTS312; 10:BTS3012A; 11:BTS3006A; 12:BTS3012; 13:BTS3006C; 14:BTS3002E; 15:BTS3012AE; 16:BTS3012 II; |
| 8 | RackNo | Number of the rack where the faulty board is located. |
| 9 | BoxNo | Number of the subrack where the faulty board is located. |
| 10 | SlotNo | Number of the slot where the faulty board is located. |
| 11 | Site Name | Site Name |
| 12 | Alarm Attribute | Alarm Character 0:Normal 1:Transient Count |
Impact on the System
- This alarm shows that the jumper side is improperly connected with the CDU. Much power transmitted from the BTS through the CDU antenna port is reflected by the jumper. Thus the power of the transmitted signals to the tower top amplifier decreases.
- Similarly, many signals the antenna feeder tributary receives from the antenna are also reflected at the CDU antenna port. Thus the power of the received signals to the TRX decreases. The BTS will turn off the power amplifier of the relevant TRX to stop power transmission.
Possible Causes
- The CDU is not properly connected with the jumper on the antenna feeder tributary.
- The feeder (including connector) is damaged.
- Such devices on the antenna feeder tributary as the tower top amplifier (TTA) and lightning arrester are damaged.
- The antenna is damaged.
Procedure
-
Check jumper connections
Turn off the power amplifier of the TRX corresponding to the CDU. Check whether the jumpers between the CDU antenna port and the feeders are securely connected.
NOTE: Turn off the power amplifier of the TRX corresponding to the CDU to stop power transmission before disconnecting the jumpers between the CDU output port and the TRX input port.
Y=> Go to Step 2.
N=> Secure the jumper connectors to the ports. Go to Step 3.
-
Measure the VSWR at the CDU antenna port
Measure the VSWR of the jumper side at the CDU antenna port using a sitemaster or another meter with the similar function. Check whether the measured VSWR exceeds the relevant alarm threshold.
Y=> Further measure the VSWR of the antenna feeder tributary, including the jumpers, lightning arrester, feeder and antenna.
N=> There might be a false alarm. Replace the CDU and go to Step [3].
-
Check whether the alarm is cleared
Secure the jumper connectors to the CDU output port and the TRX input port. Turn on the power amplifier of the TRX. Check whether the alarm is cleared.
Y=> The alarm handling ends.