Quick Installation Guide
Document
WERA4-Quick-US-200917
Page 42 of 73
5.15 Adjust Power Amplifier (PA) level (Tune Up Info Part I)
There are two power amplifier versions available. The outdoor version in a water proof box
and a rack mount version. The rack mount version is easy to handle because all displays
and knobs are at the front panel. To access the knobs, the transparent lid can be removed
(this is to prevent any accidentally “adjustments”). The adjustment is easy, turn the knob to
the left most position to start with lowest power (continue with chapter 5.14).
The
outdoor version
needs to be opened to access the adjustment switches.
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Open the PA box carefully and leave it open.
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Check that the line power voltage switch is in the correct position
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Switch all four attenuators inside the PA to “on”-position (minimum output power).
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Connect all four Tx antenna cables to the PA’s outputs. The order does not matter but
it is recommended to use an order that should be marked on the antennas and may be
noted in the log book.
If an outdoor 1 to 4 power splitter is used, the internal splitter of the PA needs to be
bridged. A coax cable is enclosed to provide a direct connection from the SMA connector
to the N-output connector, please refer to chapter 4.14.
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Leave the input of the PA open, do not connect the input cable to the PA.
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Connect the line power. The green LED should be on.
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Start a test calibration.
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Now connect the PA’s input with the Tx cable from the system output and check the
status of the LED power meter. If the power level is above the green level, the
attenuator switches might be in the wrong position or the PA is connected with a very
short cable. In that case, connect the 20 dB attenuator at the PA input.
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Normally one of the yellow LEDs of the PA’s power meter should be on. In this case
carefully increase the power level by means of the attenuator switches until the green
LED is on.
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If the PA gets into failure mode (red LED on), please make sure that the reason for this
failure is eliminated and than push the reset knob. In error mode the PA will continue
operation but with reduced gain (- 4 dB).
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Stop test calibration.
5.16 Direct path check and optimise power (Tune Up Info Part II)
Run a short calibration measurement (80 Hz frequency offset) with the PA connected and
set to minimal gain.
Check the results using “Plott_WERA_Cal_lsq
”
according to the description in pos. 11.7.
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Normally no rms voltage should be above 7 Volts
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If some voltages are higher check if the PA is really set to minimum gain
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Connect a 20 dB N-Attenuator at the input of the PA.
