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Agilent 8753E Network Analyzer low frequency spike issue..

Question asked by sschultz on Sep 28, 2006
Latest reply on Sep 30, 2006 by Dr_joel

   I work as a Test Engineer at Hubbell Premise Wiring. We use the Agilent 8753E Network Analyzer. It is calibrated every 2 weeks on schedule with the basic OPEN, SHORT, LOAD & THRU Standards. The testing I do is with C5e and C6 Cables in different Channel Configurations with Jacks and Panels.

   Here is my Network Analyzer Setup.

Averaging Factor > 1
IF Bandwidth (Hz) > 300
Z0 Impedance Std (Ohms) > 100
Power (dBm) > 10
Start Freq (MHz) > 1
Stop Freq (MHz) > 650
Number of Points > 801
Sweep Type > LIN
Curve Order > 2
Calibration Kit > User Defined
Calibration Type > 2-Port Cal
Sweep Time (s) > 5

   Testing a C6 3-Connection Channel with C6 Jack on one end and C6 Panel on the other end with (2) C6 Patch Cords at each end connected to the 1G-Baluns.

   The Spikes normally occur periodically in the 1 to 7 MHz frequency range. One spike per 1 point out of the 801 points.

   Example spike (2.6225 MHz @ -8.5 dB) would occur in Attenuation (Insertion Loss) Data of a C6 Channel.

   The Baluns are 6 years old and the contact surfaces for the wire contacts are somewhat worn. Looks like the GOLD contact surfaces are worn on the BALUN contact points.

   Is this the fault of the Analyzer or do the BALUNS need replacement?
Triple checked my Calibrations. Look OK.

   If anyone has any insight to this kind of issue, please offer me some insight. I would be extremely grateful. Thanks.