ARLP033 Propagation de K7RA
QST de W1AW
Propagation Forecast Bulletin 33 ARLP033
From Tad Cook, K7RA
Seattle, WA August 15, 2006
To all radio amateurs
SB PROP ARL ARLP033
ARLP033 Propagation de K7RA
This is a special early edition of the propagation bulletin,
threedays 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
When I first heard of this on Monday morning, I thought
it must besomething 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:
A web page from the University of Otago describing
the research is here:
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 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
processesin 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 tofly 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
If you would like to make a comment or have a tip
for our readers, email the author at, email@example.com.
For more information concerning radio propagation,
see the ARRL Technical Information Service at
For a detailedexplanation 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
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 Aindices 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.
73 de Larry W2LJ