TWiRT Ep. 815 - LDMOS Technology in FM Transmitters with Paul Barzizza

ow can a modern FM transmitter produce 10,000 watts of RF power from such a surprisingly compact package? On episode 815 of This Week in Radio Tech, GatesAir’s Paul Barzizza joins Kirk Harnack for a close look inside the company’s new GX Series of FM transmitters. Paul draws on his extensive radio and television engineering background to explain the GX amplifier layout and the powerful LDMOS field-effect transistors at the heart of the design. Because these devices spread heat across a larger area, they can handle substantially more power than earlier generations of transistors—giving transmitter designers a way to produce impressive RF output from a comparatively small cabinet. This isn’t merely a discussion of specifications and theory. Paul and Kirk recently installed a GatesAir GX10K—a combined FM exciter and 10,000-watt RF amplifier—at WIQQ-FM in Leland, Mississippi. They share photos from the project, examine how the transmitter is assembled, and talk through the technology that makes it work.