Why does a power meter show the CAL OUT power to be 2-3dB higher than specified on the 8590 Series Spectrum Analyzer?
The front panel CAL OUT signal contains a significant harmonic content. The power meter will read a higher power due to the harmonics of the calibrator. This may be eliminated by using a low pass filter. The correct measurement procedure is given in the 8590 Series Analyzers Calibration Guide, part number 08594-90183