Friday, 19 June 2009

July '09

Propagation Forecast
The Boulder A, and K indices will remain at their ‘norm’ of 5 and 2 until the end of June when there will be a disturbance on the 30th with the ‘A’ at 5 and the ‘K’ at 3. Things should return to normal by 2nd July with the A and the K back to 5 and 2 respectively. The Solar Flux however, will go from 68 to 70 around 26 June, dropping back to 68 by July 10th.

Mystery of the Missing Sunspots, Solved?
The sun is in the pits of a century-class solar minimum, and sunspots have been puzzlingly scarce for more than two years. Now, for the first time, solar physicists might understand why.
At an American Astronomical Society press conference in Boulder, Colorado, researchers announced that a jet stream deep inside the sun is migrating slower than usual through the star's interior, giving rise to the current lack of sunspots. Rachel Howe and Frank Hill of the National Solar Observatory (NSO) in Tucson, Arizona, used a technique called Helioseismology to detect and track the jet stream down to depths of 7,000 km below the surface of the sun. The sun generates new jet streams near its poles every 11 years, they explained to a room full of reporters and fellow scientists. The streams migrate slowly from the poles to the equator and when a jet stream reaches the critical latitude of 22 degrees, new-cycle sunspots begin to appear. Howe and Hill found that the stream associated with the next solar cycle has moved sluggishly, taking three years to cover a 10 degree range in latitude compared to only two years for the previous solar cycle. The jet stream is now, finally, reaching the critical latitude, heralding a return of solar activity in the months and years ahead.
"It is exciting to see", says Hill, "that just as this sluggish stream reaches the usual active latitude of 22 degrees, a year late. We finally begin to see new groups of sunspots emerging." The current solar minimum has been so long and deep, some scientists speculated that the sun might enter a long period with no sunspot activity at all, akin to the Maunder Minimum of the 17th century. This new result dispels those concerns. The sun's internal magnetic dynamo is still operating, and the sunspot cycle is not "broken." (NASA Science News 17 June 2009)

CQ Magazine Propagation editor challenges Solar cycle 24 Predictions
CQ magazine's Propagation Editor is challenging the accuracy of the newest predictions on Solar Cycle 24. The revised prediction, issued in late May by a panel of solar experts, suggests a weak sunspot cycle with a peak in 2013. But CQ Propagation Editor Tomas Hood, NW7US, is asking "How Credible Are These 'Experts'?"
In an online commentary posted on the CQ magazine website, Hood notes that this same group of so-called "experts" has issued multiple predictions for this cycle already, all of which they now say are wrong, and asks why we should believe they're right this time.
Hood points out that, while the Sun itself is millions of years old, scientists have been tracking solar activity for just a few hundred years. "In my view," he says, "it is pretty arrogant to postulate that mankind has any real understanding and handle on what the Sun might do next. If none of the models are totally correct, how are they making this current prediction with such dismal expectations? I'm not holding my breath in favour of supporting any of the predictions at this point." He also points out that there are already signs of "an awakening Solar Cycle 24," and encourages hams to "enjoy the unique propagation opportunities currently presenting themselves during this quiet phase," and to "prepare now for whatever the sun will do by honing your radio skills."
( Via Southgate ARC and Mike Terry)

HUF, MUF and LUF Charts
Ken Fletcher sent me a link to some useful charts of the Highest, Medium and Lowest useable frequency charts which can be downloaded from the ARRL website in PDF format. These regional charts are based on average readings for June ’09, and some may remember similar charts being published in Wireless World. Charts can also be found at:

Links to these articles can be found at: