FSEX30; FSE-B7; FSIQ: UNCAL and UNDERL  FAQ overview
 
Question: UNCAL and UNDERL appear as small red letters on the display. What do they mean?
   
Answer: UNCAL: Press the button CAL to start a total calibration. Watch the display. If messages are displayed, please note them. The messages should disappear after the calibration process has been finished .
UNDERL: In the vector analyzer mode (FSIQ or FSEx+FSE-B7) this message indicates that the signal level at the ADC is below the optimum range. Remedy: Reduce the reference level of the instrument until the message disappears.