[Waverley ARS] Propagation INTERESTING READING
vk2sob at box701.com
vk2sob at box701.com
Thu Aug 17 13:37:38 CEST 2006
>
> A newspaper article on Monday out of New Zealand reported a proposed
> Defense Advanced Research Projects Agency (DARPA) project that could
> cause major worldwide disruptions to HF radio communication and GPS
> navigation. The ''Radiation Belt Remediation'' (RBR) system is
> envisaged as a method for protecting low earth orbit (LEO)
> satellites from damage caused by high altitude nuclear detonations
> or severe solar storms. Testing the system would use extremely high
> intensity very low frequency (VLF) radio waves to flush particles
> from radiation belts and dump them into the upper atmosphere.
>
> When I first heard of this on Monday morning, I thought it must be
> something from a fringe web site peddling dark conspiracy theories.
> But the newspaper reporting the news is real, and so is the team of
> scientists from New Zealand, the UK and Finland whose study of
> possible effects of the scheme is reported in a recent edition of
> Annales Geophysicae.
>
> You can find the article here:
>
> http://www.physics.otago.ac.nz/research/space/ag-24-2025.pdf
>
> A web page from the University of Otago describing the research is
> here:
>
> http://www.physics.otago.ac.nz/research/space/RBR_Media_release_8Aug06.htm
>
> I contacted the lead researcher on the team reporting the possible
> effects of the project, Dr. Craig Rodger of the Physics Department
> at the University of Otago in Dunedin, New Zealand. He proved very
> cooperative, accessible and helpful, and told me RBR is a serious
> project, ''money is starting to appear to investigate it in more
> detail'', and ''U.S. scientists with military connections are treating
> it seriously''.
>
> It is feared that testing the system could shut down worldwide HF
> communications for several days to a week, rendering the ionosphere
> a giant sponge for RF.
>
> I sent Dr. Rodger a comment from Ward Silver, N0AX, who speculated
> ''the sheer energy needed to accomplish it would tend to rule it out
> from the start, and I don't know where they would erect the
> necessary antennas.''
>
> Dr. Rodger responded, ''This would be true, but they are hoping to
> rely on some of the non-linear processes in space plasmas, stealing
> the energy from the radiation belts to get the wave-amplitudes high
> enough. We know this is possible (in theory), as it happens
> naturally already. We don't know how easy it will be to get it
> happening under our control''.
>
> ''Also, as for erecting the antenna, there are two plans. One is to
> fly VLF antenna in space. This could be a power problem. But for
> ground-based systems, you probably already know that most major
> naval powers have big VLF transmitters dotted over the globe. (Two
> of the US Navy transmitters radiate one megawatt). While these are
> designed to keep the signals mostly under the ionosphere, it shows
> the possibility for building big powerful antenna''.
>
> You can read Monday's article from the New Zealand Herald, here:
>
> http://www.nzherald.co.nz/section/story.cfm?c_id=1ObjectID=10396164
>
> Tad Cook, K7RA
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