The calibration process is carried out within an anechoic chamber (designed to prevent spurious microwave signals caused by reflections). Within this chamber, the instrument is exposed to a linearly polarized (EM) field, approximating a plane wave. The axis of the probe is placed parallel to the direction of propagation and aligned with the antenna bore sight.
The EM field is rotated about the probe axis to determine the average sensitivity and to ensure that the ellipse response of the instrument remains within the +/-1dB tolerance as per the recommendation of the IEC60335-2-25-A2/Ed.6
The actual power flux density at the point of reference (assumed to be 50mm behind the probe spacer tip) is then determined.
All instruments are calibrated prior to dispatch at a single cardinal point of 5mW/cm2 and the calibration factor is set to ensure the displayed average ellipse response of the instrument is centred upon the 5mW/cm2 standard signal.
All measurements are traceable to the UK National Physical Laboratory
Note
Beneath the TX2000 battery cover there are two small switches located on the left hand side of the battery and two photo-sensors located on the right hand side of the battery. These items form part of the instrument calibration system and provide a means to adjust the calibration factor during the calibration process. The setting of the switches and the sequence in which they are operated is important.
The switches should not be adjusted unless a competent technician is to perform a calibration procedure. Improper use of these switches may lead to changes within the calibration factor and subsequent inaccuracy.
calibration is achieved by placing the instrument within a “cradle”, incorporating a fibre optic link, allowing adjustment while the instrument is within an anechoic chamber. This allows for a rapid and accurate calibration process.
Details of the procedure to be used for calibration may be obtained by contacting Celtek Electronics Ltd on +44(0)161 282 9615 or by e-mail via sales@celtek-electronics.com
To arrange for a calibration price, please contact Celtek Calibration Ltd
Tel: +44(0)1253 820200Â Â Â Â Â Â Â Â Â Â Â Â Â e-mail: sales@celtekcal.com