Cisco Cisco 1 GHz GainStar Amplifier Installationsanleitung
Chapter 4 Troubleshooting
Low or Degraded Reverse RF Signal
The reverse RF signal can be measured at the GainStar Line Extender module
reverse input and reverse output test points.
Low or Degraded Reverse RF Signal Troubleshooting Table
Before you begin troubleshooting for a low or degraded reverse RF signal, verify
that the GainStar Line Extender is receiving the proper reverse RF input signals from
the downstream amplifiers at the GainStar Line Extender module reverse input main
test point.
Important: You cannot balance the GainStar Line Extender without the proper
Important: You cannot balance the GainStar Line Extender without the proper
reverse RF input signals.
Make sure you have configured the GainStar Line Extender module according to the
Make sure you have configured the GainStar Line Extender module according to the
specifications in the design print, and that the GainStar Line Extender has warmed
up for approximately one hour.
Make sure you are using the proper total tilt reference when setting receive levels.
Refer to the reverse equalizer charts in Technical Information for more information.
Make sure you are using the proper total tilt reference when setting receive levels.
Refer to the reverse equalizer charts in Technical Information for more information.
Possible Cause
Solution
Low or degraded reverse RF signal at
the reverse input test point(s).
Verify that the line extender is receiving the
proper reverse RF input signals from the
downstream amplifiers.
Important: You cannot balance the line extender
Important: You cannot balance the line extender
without the proper reverse RF input signals.
There is proper reverse RF signal at the
reverse input test point, but low or
degraded signal at the reverse output
test point.
Measure the main reverse input test point and
the reverse output test point. Subtract the
reverse amplifier gain and add the pad values
and EQ insertion loss to verify proper reverse
amplifier gain.
Verify that all the proper accessories, pads, EQs,
Verify that all the proper accessories, pads, EQs,
Reverse amplifier, and signal directors (if
applicable) are firmly installed in the correct
locations.
Verify that the factory installed accessories are
Verify that the factory installed accessories are
firmly installed in the correct locations.
Verify that any unused RF ports are properly
Verify that any unused RF ports are properly
terminated.
Use a spectrum analyzer to look at the reverse
Use a spectrum analyzer to look at the reverse
RF input signal spectral quality at each reverse
input test point and compare it with the reverse
RF output signal spectral quality.
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