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.

• Software Manual
• Circuit Description
• Source code tar ball

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.

Last updated Fri Sep 23 10:50:30 2022