User's Manual

D-MBR 3707-3708 PS NFPA CLASS B SIGNAL BOOSTER
PRODUCT DESCRIPTION AND USER’S MANUAL
www.cobham.com/wireless Cobham Wireless – Coverage
Date: 6-Set-15
Page | 22 Doc. No. 00060CDUM Rev. 1.0
3.6.1 Verifying Isolation between Donor and Service Antennas
Note the following:
• The isolation between the Donor and Service antennas is critical especially for high gain, outdoor
applications.
• For proper operation of the Signal Booster, it is recommended that the isolation between the
Donor and Service antennas be at least 15dB higher than the Signal Boosters set gain. (Lower
isolation can lead to high in-band ripple, oscillations and low signal quality.)
• Ensure proper vertical or horizontal distance separation between Donor and Service antennas
To measure the isolation, proceed as follows:
1. Inject a known signal from a signal generator into one antenna (preferably the Donor antenna).
2. Measure the coupled output from the Service antenna, using the Spectrum analyzer and LNA if
applicable.
3. Perform this procedure across the frequency range of both the Uplink and Downlink bands.
4. Register the lower result for system operation.
3.6.2 Verifying the Link between the BTS and the Signal Booster
This test checks the signal strength from the BTS antenna to the Signal Booster.
Proceed as follows:
1. Using a Spectrum analyzer, measure the received signal from BTS at the Donor antenna port
near the Signal Booster.
2. Adjust the Donor antenna direction to receive the maximum signal strength.
3. Compare the received signal strength with the calculated signal strength from the design phase.
In case of discrepancy, check for one of the following:
• Antenna out of direction
• Antenna tuned to side lobe instead of main lobe
• Antenna connector or antenna cable faulty
• Line-of-sight problem (obstruction), etc.
4. Register the signal strength of the downlink channel for the system operation phase.