There are times when you wonder if your receiver and antenna are really working as they should. The band is dead, or empty, it’s the middle of the day, the D-Layer is sponging up every radio frequency excitation. Perhaps you can hear a few signals, but they are fleeting — and you need a steady and predictable signal source for a proper test. An RF signal generator will give you a steady carrier, but there are times when you’d prefer to have a true CW beacon to tune onto. This simple, general purpose multiband CW beacon can be run up on the frequency (or frequencies) of your choice, is powered on a 9V transistor radio battery, and can moved to attenuate to the desired signal level, for radio receiver system testing purposes.
This beacon transmits a hard-coded message in morse code on any frequency supported by the si5351 (10kHz to 160MHz). The code targets an Arduino Nano, Uno or bare ATMega328P and an si5351 breakout board. No display is necessary. You can add one, and controls, if you like. The code includes a simple CW keyer for manual sending (not used, but left in place for this application).
Any number of frequencies in the HF and VHF range can be specified by adding them to an array of transmit frequencies. The beacon iterates over the array and transmits the message on each frequency in sequence. The beacon’s CW speed is configurable. Sidetone is available as a 5v square wave on the D7 output. There is no support for switched low pass filters but this would be easy to add.
The Github repository is here.