This circuit for the 40 MHz band was published in Radio Electronics magazine in December 1957. Its purpose was to monitor the signals of the Russian satellite launched at the time.
This circuit adds a beep to turn on with car flashers that do not have this feature. A 47 ohm to...
Depending on the value of C1, this oscillator can produce signals of up to 1 MHz. For a capacitor of 10...
This commercial circuit, sold under the designation H531 in Japan in the 1960s, used three...