I work in a test-support role supporting a bluetooth production line. We use HP spectrum analysers in our final test solution and the solution to a lot of our fails is solved by calibrating these analysers. Normally we do both a Freq/Amplitude calibration and a YTF Slope calibration. Does anyone know what a YTF Slope calibration does and if we are wasting our time by using it? The majority of our fails are either TX Drift, TX Error or Deviation after Alignment fails.