Sixty years ago this month, the October 1968 issue of Popular Electronics carried a project, many variations of which have appeared over the years. It’s a “stolen power” receiver.  It consists of two crystal sets, one to tune in the desired station and another to supply power to the one-stage audio amplifier.

The “power” section is tuned to the strongest local station, which provides a DC voltage of a few hundred milliwatts, enough to power the CK721 transistor audio amplifier. The other crystal set tunes in the station, whose audio is amplified for listening.

To operate, a station is tuned in, and the power section is tuned until maximum volume is achieved. This tuning is then left alone.

According to the article, with a good ground and strong enough local station, the set could come to life with just a metal lamp serving as antenna. For optimum reception, a 50-100 foot outdoor antenna was recommended.