LFXMIT a QRP Low Frequency SDR Transmitter

A question asked on a local social net: "Why ham radio?". One of the replies was, "I can make a transceiver out of parts in my junk box when all else fails." Accepting this as a challenge with a junk box that no longer includes vacuum tubes and high voltage capacitors, but has many last generation micro-controllers, surface mount discrete components and support chips, I set out to build a low frequency QSS QRP transmitter. Purchasing a few components, and laying out a PC board (and correcting it), programming the controller and understanding the frequency synthesizer, I have a low power, software controlled CW transmitter for the 2200, 630, 160, 80, and 40 meter bands. It can be controlled by a PC through a USB port or operate stand-alone as a telemetry device sending Morse code at QSS speeds to a fast as you might wish.

System Requirements

Software is reasonably portable to any Silicon Labs C8051 with 65k flash and a minimum of 4k of RAM. Compilation of the source code requires the Small Device C Compiler. This code was compiled and tested with the Linux version.

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Last updated Fri Sep 23 10:50:30 2022