The Model 184A Power MOSFET Modulator, Magnetron Transmitter is designed to operate magnetrons up to 75 kW. The pulse width is fixed at 0.25 microseconds, at PRF up to 4 kHz. The Model 184A Modulator is not damaged by magnetron arcs. Arc energy to the magnetron is limited which actually helps to clean-up an arcing magnetron. The Model 184A Modulator is a proven, reliable design which replaces the original Model 184 design with over 30 years of field use. The new modulator HVPS is a very efficient, duty cycle regulated DC to DC converter design. Photographs of the output spectrum and detected RF are included.