S820E Microwave Site Masterâ„¢ User Guide : Calibration, VNA : Calibration Setup : Thru Device
 
Thru Device
After you have set up Port 1 and Port 2 DUT and cal kits, you must also set the Thru Device that is used in the Thru step of the calibration that is being conducted, if applicable. The Thru device accounts for any extra length that is used during the calibration steps (such as an adapter) but is removed for the actual measurement of the DUT. In these cases, if the Thru device length is not accounted for, then the resulting measurements will have an offset error.
The Thru device length can be set in units of distance or time, or it can be set to equal the Thru length offset of the cal kits that are used for Port 1 or Port 2, if applicable. Figure: Thru Device Setting shows the selection window for the Thru device setting.
Thru Device Setting