I have! And I think it’s brilliant.
When I started performing field activations in CW a few years ago, I gravitated from using 73 to 72 at the end of my exchange. I saw it as a simple and clear way to let the other op know I was running QRP.
I got so many questions about my use of 72, though (as in a few emails or comments per week) I finally wrote this blog post so I could link to it in my replies.
These days, I hear 72 being used routinely and I love it!
72 is like a simple calling card to tell the other op know you’re running QRP power.
It’s all the better when both sides sign with 72–then it feels more like a QRP handshake!
72 de K4SWL