At the bottom right hand corner of the waterfall display on WSPR 2.0 is a small red rectangle with a figure it giving a number of Hz. This number varies on my display. I've looked through all the references that I can find but nowhere can I find an explanation as to what this figure means.

It's probably stunningly obvious - once you know the answer - can someone please enlighten me?

73

Alastair G3ZHZ