The base VNA factory receiver calibration will be on by default so the unratioed response parameters can read-out correctly in dBm (and units will be displayed as such with markers on Power Out and Power In graph types) referenced to the test port of the instrument. For power reference planes at some other point (e.g., at the end of a cable), a user receiver calibration is required as discussed elsewhere in this Guide. As of the writing of this chapter (mid 2022), factory receiver calibrations do not exist for ME7838X systems or four port systems so user receiver calibrations are always needed in those cases for ‘valid’ dBm readings.

As with the other applications, the receiver calibrations proceed by transferring power accuracy (either from the factory ALC calibrations, which always exist, or a user power calibration). The sources will be turned on for receiver calibrations but will automatically use the full frequency list (not the source frequency only).

While it is something of a tautological measurement, the use of the internal source (acting as a tracking generator) after a receiver calibration can give some evidence of calibration completion and that there is internal consistency. A plot showing such a measurement is in Figure: Example: Measurement with the tracking source still connected to the receiver port just after a receiver calibration..