Turn your logic-level outputs into slightly more powerful signals! This design is one I have been using in the WSPRSONDE, and I’ve found it to be so useful that I put it in a little box along with a USB C power connection and a couple of indicator LEDs.

This will require a low-pass filter to convert the square wave output to a spectrally-pure-meets-all-FCC-regulations signal, but that’s pretty simple. This design easily covers all the ham bands between 160 and 6 meters.

Equipment using this amplifier circuit has been continuously transmitting for several years, from the steamy jungles of Costa Rica to the frozen wastes of the Arctic and Antarctic, The design and performance is thoroughly described in the product guide.