Review the General Troubleshooting recommendations before proceeding with this section.
This troubleshooting procedure assumes the PNA successfully passes the Power Level Accuracy (Source Power Accuracy) Test.
A failure in the System Crosstalk Test generally indicates one of the following:
loose cable connections or mountings within the network analyzer
degradation in the signal isolation in a step attenuator
degradation in the signal isolation in the receivers
degradation in the signal isolation on the A16 Test Set Motherboard (RF PNAs) or the A35 Receiver Motherboard (microwave PNAs)
Rerun the test. If the failures repeat when the analyzer is retested, open up the analyzer, check the connections on all the RF cables and ensure that all of the screws in the test deck are torqued properly.
If the crosstalk failure is asymmetrical and the PNA has two step attenuators, there is a strong possibility that the step attenuator on the source is causing the problem. Replace the suspected attenuator with a short cable or swap attenuators. Retest crosstalk. If the PNA has a single step attenuator, replace the attenuator with a short cable then retest crosstalk.
Identify the two receivers involved in the ratioed measurements that fail in this test. Consider swapping receivers within the PNA to attempt to identify the receiver causing the failure. Receivers in the PNA are identical. If the failure does not appear to be caused by a receiver, consider replacing the motherboard.
Refer to the appropriate PNA service guide for specific troubleshooting suggestions and replacement procedures.