Sometimes, it is useful to transmit a low-power radio signal to create a beacon, to send a signal carrier to a near receiver, to transmit in QRP or QRPP mode, and so on. The circuit shown here is very ...

If you cultivate an interest in building radios it’s likely that you’ll at some point make a simple receiver. Perhaps a regenerative receiver, or maybe a direct conversion design, ...

A simple fm radio transmitter circuit which covers frequencies from 88 to 108 MHz. It is built with 3 transistors: BC109, BFR91A and BFR96S. It is quite stable and the output power is around 200 mW.

Early radio receivers and record players nearly always had a knob marked “tone,” which was usually a crude low-pass filter with some form of severity adjustment. At best, these controls could ...