User's Manual

Repeater Operation
3-4
3-2.2.7 Auto-Leveling Control
The Auto-Leveling Control (ALC), when enabled, commands the repeater to maintain the downlink
path RF output power level indicated in the “Level” box, +/-2dB, by automatically adjusting the
downlink gain as appropriate up to the maximum power of the specific unit. (The valid range for
ALC is 0 to 27dBm for the R1910 and 15 to 41.5dBm for the R1920.) When ALC is enabled,
control of the downlink path gain is no longer allowed. The downlink gain display box will turn into
a status indicator displaying the current gain setting, as controlled by the repeater. Valid range for
ALC is based on modulation format. Use of ALC is not recommended if there are ANY gain
settings that produce oscillation.
3-2.2.8 Reverse Tracking Control
The Reverse Tracking, when enabled, commands the repeater to keep the uplink path gain at the
“Offset” level from the forward path gain. For example, suppose that the forward gain had been set
to 68dB, and the Reverse Tracking level set to -4dB. When Reverse Tracking is enabled, the reverse
gain would be automatically set to 64dB. When this feature is enabled, manual control of the uplink
gain is no longer allowed and the gain setting shown is under the automatic control of the repeater.
Reverse Tracking is limited to +/- 10dB.
3-2.2.9 Received Signal Strength (RSS)
The “Donor RSS” parameter is a graphical display of the received (input) signal strength in the
downlink RF path.
3-2.2.10 Oscillation Test
The “OSC Test” button initiates the oscillation test function. The purpose of the oscillation is to
check the isolation between the donor and server antennas. Ideally, the test should only be performed
on an unused channel to avoid unnecessary interruptions of a working network. When the oscillation
test button is pressed the operator is presented with a window asking for the channel number to use
for the test. Enter the channel numbers and press “OK” to start the test, or press “Cancel” to quit.
The application disables ALC and Tracking, if enabled, and raises the gain of each RF path by
approximately 14dB, and monitors the oscillation alarm. The test takes approximately 15 seconds.
When the test is complete, the gain, ALC, and Tracking settings are restored to their original
settings. If an oscillation alarm occurred you must clear the alarm by pressing the “Clear Alarms”
button on the alarm window.
Note: Watkins-Johnson repeaters incorporate an over power protection algorithm. This algorithm
detects when the repeater is transmitting at a power level above that allowed by the FCC. The
repeater continuously reduces the gain of the repeater until the output power is reduced to an
acceptable power level. An Osc/Max Pwr alarm is generated when this occurs.