Simple Morse beacon keyer updated 2014/03/01


Above is a clip from W4HBK’s 40m grabber today, the signal is VK2OMD running 5W QRSS6 over a 14,700km path. We can infer (Duffy 2012b) from the 15dB S/N in that capture in 0.25Hz noise bandwidth, that in an 800Hz CW filter for say -5dB S/N (threshold of copy) we need 15dB more signal, or 160W for reliable copy. (Less power may be adequate for very short QSOs at the peak of fade cycles.)

In response to requests, I have ported the simple Morse beacon keyer (SMBK) to ATmega168/328 so that it will run on a range of Arduino boards using those chips.

NanoAbove, an Arduino Nano board.

Note that SMBK is not an Arduino application, but will run on suitable Arduino compatible hardware as discussed at Simple Morse beacon keyer.


  • Duffy, O. 2012. Simple Morse beacon keyer. (accessed 01/03/2014).
  • ———. 2012b. Making inferences from QRSS grabber observations. (offline).