User's Manual

UM-0101-01.09 – November 2009

Automatic Gain Control (AGC)

Automatic Gain Control circuitry is intended to keep repeater’s output power at a fixed level

when input signals exceed maximum values, avoiding quality signal degradation by

intermodulation generation.

When AGC is active AGC UL and/or AGC DL leds will be ON, this means that signal level from

donor and/or service area site, plus repeater gain produces an output power that is above the

maximum composite output power of the repeater. This should not be considered an undesired

working condition, far from that; this is the best operating condition because you are getting the

maximum composite output power available from the repeater.

Anyway is a good practice to increase attenuation (reducing gain), until AGC led turns off, this

operation releases AGC circuitry dynamic range.

Also is a good practice to check signals from donor site to ensure that undesired signals are not

being amplified by the repeater, or even desired signal levels are not excessively high taking

repeater to an overload condition.

Overload Protection

When AGC circuit reaches its limit, the power amplifier stage is shut down to prevent harmful

distortion and potential damage to the repeater. After approximately ten seconds the system

checks if overload condition is still present, if this happens, amplifiers will remain off. This cyclic

check will continue until condition that makes AGC circuitry reach its limits disappears.

Conditions that can cause AGC to reach its limits include the presence of one or more very

strong channels, a strong in-band noise source, or amplifier oscillation due to poor antenna

isolation.

Downlink Signal Indicator

Summarizes downlink repeater output. Indicates bad, poor, good, very good and excellent signal

levels as follows:

Bad RSSI, all leds off

Poor RSSI, first led ON

Good RSSI, first and second leds ON

Very Good RSSI, first, second and third leds ON

Excellent RSSI, all leds ON

Laboratory Measurements

For specific parameters verification and laboratory tests, please contact factory.

Detailed procedures, recommended tests set up, and a knowledge engineering team will bring

adequate support to perform this measurements in a comfortable and safely way.