User's Manual

MBSC0800-040-RU
MBSC0800-040-RU July 02, 2014
Page 61
5.4.4 Link Verification
The MBSC0800-040-RU system is equipped with features that enable the downlink and uplink link to be
fine-tuned from the head-end location using common test equipment (RF signal generator and RF power
detector).
5.4.4.1 Verify End-to-End Downlink Gain
Each RU in the remote node is equipped with a calibrated Downlink Power Detector which will display the
average power at the output of the RU. By injecting an RF CW signal at each TXin port of the BIU the
end-to-end downlink system gain can be verified without additional test equipment required at the Remote
Node.
Verify the end-to-end Downlink Gain for each frequency band as follows:
1. Using an RF Signal generator inject a CW RF signal to the TXin port of the BIU
a. Set the frequency to the center of the spectrum to be used in the system (if the operator
licensed bands are not known set the frequency to center of the band – e.g. 2132.5 MHz for
AWS band)
b. Set the input RF power level to be 3 – 5 dB below the expected RF level to product
maximum output power at the RU to avoid accidental overdrive (e.g. if the gain is set so that
0dBm input will produce +43 dBm at the output then start with -5dBm)
2. The resultant Downlink output power of the RU can be observed in two ways:
a. In the topology window the Downlink Output power is displayed next to the specific RU (e.g.
30.7 dBm indicated in the topology diagram by the 800MHz RU in Figure 52 – Up/Down Link
Verification)
b. Downlink Output Power: In the component window
3. Variations in filtering, amplifiers, and optical loss may cause the actual system gain to vary +/- 6 dB.
All paths can be normalized by adjusting downlink attenuation settings in the BIU.
4. This procedure should be repeated for each frequency band in the system