My apologies if this doesn't really fit in here, but do pass it on to anyone you think may be able to help with this scientific 'special event'.
For some years, I've been researching noctilucent clouds and their associated phenomenon, PMSE (polar mesospheric summer echoes), both of which occur June - August in the northern hemisphere. If you're new to NLC/PMSE, you can get a flavour from my BBC work of 2010: http://www.bbc.co.uk/news/science-environment-10635796
but note that PMSE are not visible to the eye as NLC are. A radar image of PMSE from July 2011 can be seen here: http://badc.nerc.ac.uk/browse/badc/mst/plots/m-mode/2011/07/radar-mst_capel-dewi_20110702_m300.png
The work, which is almost entirely voluntary, has now progressed to involve the Natural Environment Research Council's atmospheric radar at Aberystwyth (see: http://mst.nerc.ac.uk/
) and the University of Bath's (http://www.bath.ac.uk/elec-eng/research/csaos/
) meteor radar at Esrange in Arctic Sweden. As I've been picking up my interest in amateur radio recently, I wondered whether there were any specialists out there who may have in the past made use of what could have been PMSE-mediated propagation? I've come across a few forum debates about 'noctilucent cloud propagation', but I think the contributors were at the time unaware of PMSE and so not quite debating the correct phenomenon. It's fair to say that there is very little understanding of PMSE even today. From the cursory reading I've done, it seems the Chain Home radar sets of WW2 at about 20-30MHz detected enormous and unexplained reflections initially thought to be swarms of German aircraft. There is a suspicion, as merely one theory that needs fleshing out, that it might instead have been due to PMSE.
So, if you live in the latitude band 50-60 degrees north, preferably within Europe, and if you would be willing to spend some time during summer 2012 to see if PMSE mediate HF propagation (or that of other frequencies), then I'd be very interested to hear from you at: john[at]pixaerial[dot]com I'm afraid I'm not in a position to invest in the quality equipment required, nor do I have the expertise to test this out for myself. In any published work, you will be fully acknowledged and, if the publication is restricted to PMSE and radio propagation, included as an author.
I hope to hear from you soon!