Re: 10 to 50 milliwatt transceivers
Dave Ingram (SK) had the Hamfest Buddy. Rex at QRPme Made and updated Version (with Filtering) that is a no solder kit. His Schematic is on the QRPme Site.
Dave's CQ Article Link should be attached.
Now, to make either of these into "Pixie" Style, simply put an Earpiece across the 10K Emitter Resister
72 de Casey KC9IH@...