The high power microwave spectrometer is used for the study of high power microwave properties of magnetic materials. The spectrometer is used for spin wave instability threshold field measurements. The figure shows a schematic of the system at CSU. The main parts of the CSU system include a TWT amplifier, an X-band waveguide line, a reflection microwave cavity, a rotatable electromagnet, and three step motor driven precision variable attenuators. The spectrometer is used to (1) generate low duty cycle high peak power microwave pulses, (2) measure the peak power incident upon and reflected from the microwave cavity, and (3) apply the microwave magnetic field and the static magnetic field to the sample of interest. The operational frequency is 9 GHz, the input microwave pulses are 50 ms wide and the nominal repetition rate is 40 Hz. Peak input powers are in the 1-2 kW range. The system is computer controlled by Labview programs.