Black Box MWU2000-X21 manual To activate the front panel LEDs, Rssi measurement connection diagram

2.048Mbps Wireless Modem

To activate the front panel LEDs:

1.If the LEDs are not lit, loosen the screws on the U-bolt that fasten the Rx and Tx antennas to the last (or the bolts on the wall mount) and slowly move the antennas up and down (elevation) and from side-to-side (azimuth), until all four LEDs are lit (Radio - RX Sync and TX Sync, Line –RXD and TXD).

2.Tighten the screws on the U-bolt (or the bolts on the wall mount).

Step 3 – Fine tuning the adjustment of the antenna using RSSI Measurement

The RSSI (Receive Signal Strength Indicator) enables to fine-tune antenna alignment by supplying a measured value of the signal received by the unit. Maximizing the RSSI value optimises performance.

The RSSI value can be viewed using the local monitor, as described on page 72. The RSSI per channel feature displays in graphic format the strength of the received signal on each of the RF channels in use. The modem also enables to collect a measurement of the average RSSI using a DVM (digital voltmeter) connected to the RSSI test pin in the rear panel of the unit. The measured DC voltage is relative to the RSSI value as indicated in Figure 2-15. The 2.048Mbps Wireless Modem enables to perform RSSI measurement using a DVM also near the Receive Antenna. This procedure simplifies the tuning process, by allowing easier reading of the RSSI level while moving the antenna.

The RSSI measurement (with DVM or monitor) indicates the strength of reception. In order to maximize the reception strength, the receive antenna and the transmit antenna on the remote site of the link must be aligned facing each other until maximum signal quality is obtained. This procedure should be repeated on the modems on both sides of the link.

Note: The RSSI measurement indicates the strength of received signal in the 2.4 -2.5 GHz band. Verify that you are not aligning the antenna towards an undesired source of energy in this band (See also page 82).

⇒To fine-tune the antenna alignment using a DVM connected directly to the unit:

1.Connect one of the DVM probes to the RSSI test pin. Connect the other probe to the case chassis.

Figure 2-14. RSSI measurement connection diagram

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