Can anyone point to any literature on previous attempts to devise a measure of the "merit" of a spot, maybe Paul?

We look at them on the map or on a chart and try to evaluate them visually, comparing power, SNR and distance, together with what we individually know about propagation on a per frequency basis etc.

I'm suggesting SpotQ as a concept to try to derive an actual value based on the data available from a spot along the lines of Q (or quality factor) which as people know is a figure of merit used to distinguish different coil structures.

In order to throw it open and let everyone get involved I've incorporated a user customisable charting option in an update to http://wspr.vk7jj.com/

Hope it works ok, the coding is a bit ambitious.

Feel free to laugh, cry or whatever :-)

Cheers, Phil VK7JJ