This section provides steps and information to make basic power measurements with the MA24108A, MA24118A, and MA24126A power sensor and PowerXpert. To perform a power measurement:
Do not apply power greater than the power sensor specifications or permanent damage may result. Connect a fixed attenuator to the output connector when power exceeds +20 dBm.
4. Connect the RF source to the RF IN port of the power sensor. Read the power measurement from the Anritsu PowerXpert application window (power readings are continuous with the default setting).
Connecting the DUT
RF signal connections are made to the male RF connector, which has a 50 ohm characteristic impedance. When connecting to the male connector of the sensor, observe the following practice for tightening the connection:
1. While holding the body of the sensor in one hand, turn the male connector nut to finger tighten the connection. Do not turn the body of the sensor as this will cause excessive wear to the connector.
2. Back off the connection by turning the connector nut counter clockwise 1/4 turn.
3. Tighten the connection (clockwise) using a 12 in-lb torque wrench (Anritsu part number: 01-200).
Zeroing the Sensor
Zero the sensor before making power measurements. If frequent low-level measurements are being made, check the sensor zeroing often and repeat as necessary. If the sensor goes into sleep mode, the sensor must be re-zeroed before taking measurements. Before zeroing the sensor, connect it to the DUT (device under test) test port and remove RF power from the connection to a level 20 dB below the noise floor of the power sensor. For the MA24108A, MA24118A, MA24126A, MA24208A, and MA24218A this level is less than –70 dBm. Leave the sensor connected to the DUT test port so that ground noise and thermal EMF (electro-magnetic fields) are zeroed out of the measurement. The sensor may also be connected to a grounded connector on the DUT or disconnected from any signal source.
To zero the sensor MA241xxA series power sensor, click the Zero button on the application. If the sensor fails the zeroing operation, the messages “Range 1 zeroing error” and/or “Range 2 zeroing error” is displayed on the application screen until the problem is corrected.
To zero the sensor MA242x8A series power sensor, click the Zero button on the application. If the sensor fails the zeroing operation, remove power from the sensor and Zero again.
Calibrating the Sensor
The signal channel/analog signal acquisition hardware is integrated along with the RF front end of the power sensor. All calibration factors, as well as linearity and temperature corrections, are stored in the sensor. Therefore, there is no need for a reference calibration with the sensor.
Applying a Calibration Factor Correction
The power sensor has an internal EEPROM containing correction and calibration factors that were programmed into the sensor at the factory. The power sensor has an internal temperature sensor that reports its readings periodically to the microprocessor. The sensor makes all of the required calculations on the measurement once the measurement frequency has been entered in the General Settings area.
