What is antenna calibration and why is it important?
An antenna calibration is a verification of performance and the measurement of the antennas properties. Much of the success or failure of EMC test depends on the performance of a calibrated antenna.
Calibration Interval will depend on several factors:
Antenna calibration is important to ensure repeatable, reliable data and the calibration interval should be set depending on the quality system policy of the organization, conformance to your testing procedures/standard and also on the reliability of the antenna. The antenna factor of a well-designed and well-built antenna should not change provided the antenna is handled with care. If repeat calibrations show that the antenna factor does not deviate by more than the uncertainty of measurement, the calibration interval can be extended. Calibration laboratories can suggest intervals but in most cases they are not familiar with the details of the antenna or it's application. The recommended interval for the calibration of antennas by A.H. Systems is 1 year. Regular checks should be preformed in between calibration cycles. If these checks show the antenna to be in good condition and it is known that the antenna has been handled carefully, the calibration interval could be reviewed and a longer interval considered. When determining antenna calibration intervals as an antenna "owner" several other factors should be taken into consideration such as:
Recommended verification for improved antenna performance
A mechanical check should be preformed each time an antenna is used. This will ensure that the RF connector is in good condition and that the antenna elements are firmly affixed and are not bent out of shape.