Homebrew W6JL 50 Watt Amplifier for 80-17m

The resource details the construction of a homebrew 50-watt FET amplifier, based on Don W6JL's QST Homebrew contest-winning design from 2009. It functions as an afterburner for QRP transceivers, providing a 12dB power lift. The amplifier utilizes IRFZ24N FETs and covers the 80, 40, 30, and 20-meter bands, with the 20m LPF extending to 17m. Key technical aspects include an FT37-43 transformer for the input network, a relay-switched 3dB pad for lower bands controlled by an Arduino Nano, and an RF-actuated T/R switch. The LPF board integrates four relay-switched filters rated for 50 watts, using capacitors with a minimum 250VDC rating. Performance measurements indicate a power gain ranging from 4.4dB on 20m to 8.1dB on 80m, with a required drive power of approximately 5 watts. The article also discusses thermal management, current limiting considerations, and component sourcing.