User's Manual

Repeater Installation
2-8
2.8.2 ANTENNA ALIGNMENT PROCEDURE
a. Ensure correct Channel # is displayed and RF is turned ON. For multicarrier
filters, the Channel # should be tuned to the center of the desired passband.
b. Increase the Downlink gain until signal is present on RSSI.
c. Adjust Donor Antenna for maximum signal deflection on RSSI.
d. Set FWD gain to desired level.
e. When ready, click the “OSC Test” button on the windows control software.
f. After test complete, verify no Alarms are illuminated red. If yes (no alarms red),
skip to step “f”. If no (alarms illuminated red) go to “g”.
g. Reposition the Donor or Server antennas to improve isolation, or lower FWD or
REV gain settings by 4dB, clear alarms and repeat step “c”.
h. If using ALC
*
, enter ALC Level and enable. Repeat step “c”. If not go to “g”.
i. If using the serial interface, remove cable from J2, RS-232 on R1910. Test is
complete.
2-8.2.1 Effects of obstruction on RF Signal Propagation
Radio path clearance between antennas is an essential criterion for any point-to-point communication
system, and is one critical element of propagation conditions of a mobile communication system. If a
fairly large object exists in the radiation path between two antennas, reduced received signal strength
will occur because the radio link relies increasingly on energy diffracted around the obstructing
object, rather than direct (line-of-sight) radiation.
Diffraction allows radio signals to propagate behind obstructions. Although the received signal
strength decreases rapidly as a receiver moves deeply into the obstructed (shadowed) region, the
diffraction field still exists and often has sufficient strength to produce a useful signal.
2-9 FCC REQUIREMENTS ON SPURIOUS
The FCC requires that all spurious signals emanating from the repeater must be at or below -13dBm
outside your frequency band. There are several things one must consider when deploying repeaters. If
you are deploying in a single carrier deployment then there are no other calculations you must make to
verify that the FCC limits are being met. Multicarrier deployment is more complicated, but good
solutions are readily available. The preferred method is to use one repeater per carrier. This method
provides the highest composite output power without producing intermodulation products that exceed
FCC requirements. A much lower cost solution involves using a repeater with a bandwidth wide enough
to allow 2 or more signals to pass. This method provides the lowest cost solution but can limit
composite output power depending on the frequency of the signals. The two methods are detailed below.