I'm keen not to burn out the input to the spectrum analyser. It's 50 ohms in with a maximum of +30dBm. The solution is to transmit into a dummy load and sample the signal with a resistive tap.
A good candidate for a simple PCB and I used Paul Taylor, VK3HN's, technique of drawing resist on the board with a sharpie. Components are all soldered on to the top of the board so laying them out to figure out where the tracks go is easy.
Here's the circuit and the components for the board:
I've got some more of the nice board edge mounting SMA sockets coming so had to make do with a panel mount for the tap output.
What should I use to protect the copper? I think Paul just tins the whole board but maybe there's a spray lacquer that would still allow solder modifications but prevent oxidation.