Not sure if this has been mentioned on this group but an interesting piece
of software by Alex, VE3NEA, called CW Skimmer has recently been made
available, see
http://www.dxatlas.com/CwSkimmer/

Although the software costs $75 one can download a trial version (30 days).
It's interesting to see that whilst away from the shack this evening the
program correctly identified G3KEV (501.9 at 19:35) and also G0MRF (503.0 at
19:37).   The callsign picking routine must have been designed for the HF
bands, where the protocol is very mature, so got a bit confused with the
protocol used on 500kHz and eventually decided that David callsign was
IO91TK! 

It seems to need a reasonable S/N, but could be quite useful if one is not
able to personally monitor the band all of the time.  Have others tried it?

73 John, G3WKL