Fifty years ago this month, the January-February 1969 issue of Elementary Electronics reviewed the Science Fair “P-Box” shortwave receiver. The three-transistor set used one transistor as regenerative detector, with the remaining two serving as audio amplifiers. With interchangeable coils, the set covered 3-40 MHz.
I had one of these, and even though it made sound, I never did pull in any shortwave stations. I did manage to get some overload from local FM stations. I suspect if I had been more patient with the regeneration control, I actually would have received some shortwave.