User's Manual

91 080 0730F - OR2-SBLP1 SERIES Page 6 ENG Edit. 02
FIXED BAND OFF-AIR REPEATERS
• Isolation between the antennas
Since the equipment is a bi-directional amplifier, the isolation between the outdoor antenna (donor) and
the indoor antenna (service) must be at least 15dB greater that the repeater gain. For example, if the
repeater gain is 60dB, the minimum isolation between both antennas must be greater than 75dB.
To guarantee the correct isolation between the antennas, it is necessary to plan for an adequate distance
between them, both horizontally and vertically. Also walls and floors can be useful to increase the
isolation between the antennas.
• Repeater gain setting
During installation, it is necessary to adjust the equipment gain. The right calculation of the gain to be set
cannot be made without an evaluation of all the variables which characterize each installation.
The minimum gain value to be set on the up-link / down-link path is determined by considering the
maximum output power and the maximum allowed input level of the equipment (-20dBm).
The balance between losses and gains for the equipment (link budget) permits adjusting the attenuation
of the two paths (down-link / up-link), in order to reduce interferences towards the BTS and to avoid
problems connected with the isolation between the antennas. Link budget also permits checking whether
or not the output signals from the equipment (towards the BTS and towards the mobile terminals) are
adequate.
PLEASE NOTE:
The repeater has been developed to operate at maximum gain. If attenuated, maximum
output power will be reduced proportionally. ALC is always enabled.
It is strongly recommended to set the repeater gain at maximum level. Attenuation should
be set only if antenna isolation is not enough (less than 75dB).