Agilent Technologies 8719D User Manual page 289

After measurement calibration, you can change the power within a range
Note
and still maintain nearly full accuracy. In some cases better accuracy can
be achieved
different power levels for calibration and measurement to minimize the effects
of sampler compression or noise floor.
If you decide to switch power ranges, the calibration is no longer valid and
accuracy is no longer specified. However, the analyzer leaves the correction
even though it's invalid.
The annotation C? will be displayed whenever you change the power after
calibration.
Figure 6-6. Power Range Transitions in the Automatic Mode (HP 8719D/2OD, Standard)
changing the power within a range. It can be useful to set
by
Applioation and Operation Conoepts
on