Keysight N9923-90001 User’s Guide87CAT (Cable and Antenna Test) Mode1-Port Cable Loss MeasurementsA 2-port Insertion Loss measurement is usually more accurate than a 1-portCable Loss measurement. However, to perform a 2-port Insertion Lossmeasurement, both ends of the cable must be connected to the FieldFox.How to make a 1-port Cable Loss Measurement1. Press Preset then Preset.2. Then More then Cable Loss (1-Port)3. Connect the cable to be tested.4. Press Freq/Dist and enter Start and Stop frequency values of themeasurement.5. Press Sweep 3 then Min Swp Time. Increase the Sweep Time until a stabletrace is visible on the screen. The amount of time that is required increaseswith longer cable lengths. Learn more in the Supplemental Online Help:http://na.support.keysight.com/fieldfox/help/SupHelp/FieldFox.htm6. Remove the cable to be tested.7. Press Cal 5, then QuickCal or Mechanical Cal. Mechanical Cal.8. Follow the prompts to perform calibration at the end of the jumper cableor adapter. Learn more about Calibration in “How to Perform aCalibration” on page 104.9. Connect the cable to be tested.10.Connect a LOAD at the end of the cable to be tested. This limits thereflections to faults that are located in the cable under test.11.Press Trace 6 then Data->Mem to store the trace into Memory.12.Remove the LOAD and leave the end of the cable to be tested open.13.Press Data Math then Data – Mem. The ripple in the measurement isremoved. These minor imperfections in the cable should not be consideredin the Cable Loss measurement.In high-loss conditions, a Cable Loss measurement becomes ‘noisy’ as thetest signal becomes indistinguishable in the FieldFox noise floor. This canoccur when measuring a very long cable and using relatively highmeasurement frequencies. To help with this condition, use High Power(page 83) and Averaging. (page 80).Low-level standing waves (also known as ‘ripple’) which may be visible inreflection measurements, can hide the actual loss of the cable. Steps 10through 13 can minimize the ripple. Perform the measurement with andwithout steps 10 through 13 and choose the method with the least amountof ripple.
