Over on Hackaday we’ve seen a story about a Raspberry Pi Pico based software defined radio transmitter that is capable of transmitting SSB, AM, FM and CW anywhere between 0.5 – 30 MHz.
The design generates an oscillator signal using the Pico’s Programmable IO. For AM/SSB it uses the PWM output pins to generate an RF envelope which gets mixed together with the oscillator using an analog multiplexor. A small microphone is also connected to the Pico for voice transmissions. The designer notes that the output power is far too low to be used on the air, but adding an output amplifier would help.
The Raspberry Pi Pico is a low cost microcontroller board, and we note it cannot run Linux like standard Raspberry Pi boards. This means that software like RpiTX cannot be used.