[South Florida DX Association] ARLP033 Propagation de K7RA

[Bill Marx]

SB PROP ARL ARLP033
> ARLP033 Propagation de K7RA
>
> This is a special early edition of the propagation bulletin, three
> days before the regular Friday publication schedule.  The regular
> bulletin will appear on Friday, August 18.
>
> 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
>
> If you would like to make a comment or have a tip for our readers,
> email the author at, k7ra at arrl.net.
>
> For more information concerning radio propagation, see the ARRL
> Technical Information Service at
> http://www.arrl.org/tis/info/propagation.html.  For a detailed
> explanation of the numbers used in this bulletin, see
> http://www.arrl.org/tis/info/k9la-prop.html.  An archive of past
> propagation bulletins is at http://www.arrl.org/w1aw/prop/.
>
> Sunspot numbers for August 3 through 9 were 23, 0, 0, 0, 0, 12 and
> 25 with a mean of 8.6. 10.7 cm flux was 71.3, 69.6, 69.5, 69.5,
> 69.8, 71.4, and 74.1, with a mean of 70.7.  Estimated planetary A
> indices were 6, 3, 4, 4, 32, 12 and 9 with a mean of 10.  Estimated
> mid-latitude A indices were 5, 2, 2, 2, 19, 10 and 9, with a mean of
> 7.
> NNNN
> /EX
>
>