A recent thread on the qrp-l.org mailing list talks about the Michigan Mighty Mite, a one-transistor transmitter that puts out about 500 mW. Here are a couple of variations on this simple circuit:
Steve, N9OH, built his on a piece of perf board.
Tom, N2UHC, built his on a piece of PCB material that he scored to create eight pads. Then, he did a very nice job of packaging it into a candle tin. He suggests that pairing it with the AMQRP Tin Ear Receiver would make a nice little homebrew station.
Dave, WA5HJJ, has built a whole bunch of them, mostly on chunks of wood.
Todd says
My first homebrew project was a mighty mite on 80 m. With a 12 volt battery pack it puts out 3/4 watt. It has a little chirp, but I think if I adjust it somemore I can eliminate it. What a cool project. I am going to build one for 40 m soon too.
Rich says
I built one but I m not getting any voltage out on my dv meter through 50 ohm load that has detector. What are some test points I can expect through transistor