Noctilucent, very high altitude, night time visible, clouds are becoming more common and at lower latitudes. This may be a result of climate change. One phenomenon associated with these is strong microwave radar echoes, raising the possibilty of very long distance DX by reflection from these on bands like 10GHz. This is an area ripe for experimentation but I am unaware of ANY groups anywhere investigating this exciting new propagation mode.
There is a link between noctilucent clouds and the solar cycle with NLC activity peaking just after solar minimum, possibly because low solar activity allows the upper atmosphere to cool, promoting the growth of ice crystals that make up the clouds. See http://spaceweather.com/
4 Jun 2010
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2 comments:
I read your previous posts on this subject with interest. It all sounds plausible, but I'm not a microwave operator right now. I wonder how Noctilucent clouds could be tracked for propagation? Visual spotting cluster? Or how about a grid of high angle 3cms beacons - that might help produce data on the geometry of signals.
73 David, G8JGO
Also not a microwave man David. It needs beacons operating 24/7 with monitoring at intercontinental range. I am very surprised that, as far as I know, no-one is rising to the challenge of working intercontinental 10GHz DX not via the moon. Apparently radar echoes are strong, so this would be like aurora i.e. not very weak signals but strong ones when the paths open.
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