Early on in my membership to the 600m Yahoo Group I was introduced to the idea of merging multiple spectrogram captures together to sharpen the received signals. With VK2DX now having transmitted for about 24 hours on 2200m I thought I'd try my hand at it.
I simply used about 6 captures and combined them in layers in GIMP and set the layers up as 'multiply'. It was a bit of a rush job, but I'm happy with the result. I recommend having a play yourself. GIMP is free and so are all the capturing tools, so all you need is a signal and some time. 😉
(Image 1 is before, 2 is after the merging.)