Keysight N9912A User Manual page 316

Safety Considerations
Electrostatic Discharge (ESD) Precautions
Static charges are generated in numerous ways, such as simple contact,
separation of materials, and normal motions of persons working with the
FieldFox. To prevent instrument damage, practice industry accepted
techniques for handling static sensitive devices when using the FieldFox.
Very often, coaxial cables and antennas also build up a static charge, which, if
allowed to discharge by connecting to the FieldFox, may damage the
instrument input circuitry. To avoid such damage, it is recommended to
dissipate any static charges by temporarily attaching a short to the cable or
antenna prior to attaching to the instrument.
21- 10 Keysight N9912-90001 User's Guide