I enjoy building and operating RF Amplifiers. The 4CX250 is one great tube to use in your amplifier projects. Many popular HF Amplifiers feature grid driven tetrodes. This paper shows circuit information I've referenced many times through the years. It's mostly a way to show you a method of stable drive application and bias through a tuned input. Since the bias and screen power supplies are often magic to the new builder, I've also included the simple and solid circuits I like.
Proper cautions apply when working around RF and High Voltage please. The circuit features a single 4cx250 circuit with band swtiched tuned inputs for the original 80-10 bands. Often found at bargain prices, the 4cx250 tetrode is "a real bang for the buck". This is a zip file package which contains the circuit diagram in gif and Adobe PDF file formats.
enjoy
skipp
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