This circuit for low frequency data transmission was found in the May 1977 issue of Radio Electronics magazine. The circuit modulates the signal at two frequencies for bits 0 and 1.
This circuit in a receiver that allows the capture of distant stations with short waves. The...
This experimental receiver was found in an English publication in 1979. It can receive medium-wave...
This circuit was found in an Italian publication in 1975. The transistor must have a heat...