Some applications for Advantest R9211C Spectrum Analyzers include Site Monitoring: Verify that the frequency and signal strength of your transmitter is accurate. Interference: Before a system is installed you use a Advantest R9211C spectrum analyzer to verify that the frequencies (you plan to use) are not occupied or if the presence of a very strong signal will interfere with your new setup. Interference can be created by a number of different situations. Other tests that utilize the Advantest R9211C spectrum analyzer features include antenna isolation, co-channel interference, adjacent channel power, occupied bandwidth, intermodulation, microwave or satellite antenna alignment, and characterization of components.