Abstract: A RF precision calibration standard kit and calibration technique for “slotline” or slot transmission line for a network analyzer. The calibration standard kit establishes an accurate, repeatable reference plane at the slotline transmission interface. The calibration standard kit includes first and second coaxial to slot transmission line adapters, each adapter defining an adapter slot transmission line and having a slot connection port connected to an connection end of the slot transmission line and a coaxial connection coupled to the adapter slot transmission line. The kit further includes an offset component defining a section of slot transmission line, and a shorting plate. The first and second adapters, the offset component and the shorting plate are each adapted for connection to each other in a plurality of calibration configurations, including configurations for conducting Through, Reflection and Line measurements.