Verifying the InstaCal module before any line sweeping measurements is critical to the measured data. InstaCal module verification identifies any failures in the module due to circuitry damage or failure of the control circuitry. This test does not attempt to characterize the InstaCal module, which is performed at the factory or the service center.
The performance of the InstaCal module can be verified by the Termination method which is similar to testing a bad load against a known good load.
Termination Method
The Termination method compares a precision load against the InstaCal module and provides a baseline for other field measurements. A precision load provides better than 42 dB directivity.
1. Set the instrument frequency for the device under test.
2. Press the Measurements main menu key and select Return Loss.
3. Connect the InstaCal module to the instrument’s RF Out port and calibrate the Site Master using the InstaCal module requiring verification.
4. Remove the InstaCal module from the RF Out port and connect the precision load to the RF Out port.
5. Measure the return loss of the precision load. The level should be less than 35 dB across the calibrated frequency range.
6. Press the Marker main menu key and set Marker1 to Marker To Peak. The M1 value should be less than 35 dB return loss.