Posts Tagged ‘solar’

Changing propagation

If proof were needed that we are now on the way down to the next minimum then take a look at the sunspot number graphs at http://www.solen.info/solar/ .

Although conditions are sliding, do not abandon the higher HF bands like 10m. There is (usually) quite a lot of good DX around still. In the last solar minimum I was still able to work well into southern South America on 10m with QRP SSB.  WSPR should be even more reliable when conditions are edgy.

I really do hope a strong core of WSPR operators stick with 10m as, in many ways, in the poorer times are when WSPR will be most valuable as a tool. I am hoping that when not on traditional modes like SSB or CW people will still WSPR so we can catch fleeting openings, which are probably far more common than people expect on 10m. Remember, the F2  or transequatorial propagation has only to go above 28.126MHz for 120 seconds and someone on WSPR may spot it!

Solar activity

See http://www.solen.info/solar/ .

Looking at the data on this excellent page, it now looks pretty certain that we have started on the downwards part of the current cycle. This does NOT mean an end to decent HF conditions. For several years to come there will be good days and 15,12 and 10m will still support DX but far less easily than around the sunspot maximum years.

Even in the depths of the last minimum N-S DX was still there to be worked on QRP SSB, so expect some decent openings. This is really where regular WSPR operation will help, by seeing just how often 10m opens up.  As I have said before, operating on the weaker parts of the solar cycle are, in many ways, more challenging and interesting. When 10m is wide open it becomes too easy.

Also, don’t forget Es (sporadic-E) which can produce some spectacular DX at the right time of the year – in the northern hemisphere this is usually May, Jun, July and August but Es can occur (more fleetingly) at other times times of the year. This is why regular WSPR operation will help.

Sunspots slowly falling?

Today’s sunspot count is 65 with “normal” 20-30MHz conditions. It looks to me as if the solar activity is now on the slide downwards. This does not mean an end to good conditions. This autumn 15, 12 and 10m should still be in very good shape and it will be a few years before we really see the changes.

There are all sorts of predictions about the next few cycles. The consensus is the next few cycles will be ones with low solar activity. It is still too soon to say if we are really entering another Maunder minimum. Don’t worry: this is a chance to explore HF in different times. There is unlikely to be good (any) E-W F-layer propagation on 12,10 and 6m but N-S propagation will be possible some of the time and openings on Es can be surprisingly distant in all directions at the optimum times of the year.

And there are always VHF, UHF, microwaves and nanowaves to explore!

See the coming months and years as a challenge. We may never see really good conditions again in our lifetimes but there will still be interesting propagation and DX to be worked and heard.

An Amazing Moment in Space Weather – Massive Solar Eruption June 2011

While many are talking about how Solar Cycle 24 is the weakest since the Maunder Minimum (the period starting in about 1645 and continuing to about 1715 when sunspots became exceedingly rare, as noted by solar observers of the time — see this Wiki entry), there are moments when activity on the Sun strongly increases, providing brief moments of excitement.

Here is a case in point, witnessed by the Solar Dynamics Observatory (SDO; see SDO Mission) on June 7, 2011, when the Sun unleashed a magnitude M2 (a medium-sized) solar flare with a spectacular coronal mass ejection (CME). The large cloud of particles mushroomed up and fell back down looking as if it covered an area almost half the solar surface.

SDO observed the flare’s peak at 1:41 AM ET. SDO recorded these images in extreme ultraviolet light that show a very large eruption of cool gas. It is somewhat unique because at many places in the eruption there seems to be even cooler material — at temperatures less than 80,000 K.

This video uses the full-resolution 4096 x 4096 pixel images at a one minute time cadence to provide the highest quality, finest detail version possible.  The color is artificial, as the actual images are capturing Extreme Ultraviolet light.

It is interesting to compare the event in different wavelengths because they each see different temperatures of plasma.

Credit: NASA SDO / Goddard Space Flight Center

Video: http://g.nw7us.us/1aOjmgA – Massive Solar Eruption Close-up (2011-06-07 – NASA SDO)

Visit: SunSpotWatch.com

 

Show Notes #104

Episode #104 Audio (Listen Now):

Introduction:

  • Pete is back on the show along with Russ

Announcements:

  • Hamvention 2013 is happening May 17-19, 2013 in Dayton, Ohio. LHS reached the donation goal and thus will be in the Hara Arena. Thanks to Sierra Radio Systems for their incredibly generous donation that put us over the top. We will be talking with George from Sierra and Nick from Pignology in Episode #105. It’s a show you DO NOT want to miss.
  • Bill, KA9WKA, has announced that he is also going to be on hiatus for a while. Therefore, we now have an opening for a show notes taker and keeper of all knowledge! If you’d like to be that person, please send us an e-mail or get in touch with Pete or I in the IRC channel.
  • Website that lists known Linux Events.
  • http://answers.oreilly.com/topic/3507-list-of-known-linuxfest-events/

Topics:

Feedback:

  • Topic for short discussion: How is Ham Radio Free and Open Source?
  • Due to the length of the interview with Steve Nichols, feedback will be moved to after the interview in Episode #105.

Contact Info:

Music:

 

LHS Episode #104: Propagation 101 with G0KYA

Steve_Nichols_220412_smallWe sometimes on this show attempt to bring you interesting interviews with people who are both computer literate and ham radio literate at the same time. In this case, we bring a scholar, physics buff, aerospace engineer and brilliant guy, Steve Nichols (G0KYA), to discuss the science of radio wave propagation. No need to turn the show off before it even begins. Steve makes understanding the Earth’s atmosphere, its magnetic field, and a ton of stuff about the sun simple and approachable. No mind-bending equations, no physics lectures, just some great information for anyone interested in learning how a radio signal gets from here to there. A bunch of follow-up information in the form of books and Web sites are provided as well, links to which will be in the show notes, for anyone who wants to further their education. Thank you as always to our loyal listeners. Make sure to tell a friend next time you’re out for a cold one. The more the merrier.

73 de The LHS Guys

Geomagnetic data reveal unusual nature of recent solar minimum

An interesting article appeared on physorg.com yesterday regarding changes in the Earth’s magnetic field and its relation to solar activity. Although short on detail it hints at significant changes going on within our sun.

Since the mid-1800s, scientists have been systematically measuring changes in the Earth’s magnetic field and the occurrence of geomagnetic activity. Such long- term investigation has uncovered a number of cyclical changes, including a signal associated with 27-day solar rotation.

This is most clearly seen during the declining phase and minimum of each 11-year solar cycle, when the Sun’s magnetic dipole is sometimes tilted with respect to the Sun’s rotational axis. With the Sun’s rotation and the emission of solar wind along field lines from either end of the solar magnetic dipole, an outward propagating spiral-like pattern is formed in the solar wind and the interplanetary magnetic field that can drive 27-day, and occasionally 13.5-day, recurrent geomagnetic activity.

Recurrent geomagnetic activity can also be driven by isolated and semipersistent coronal holes, from which concentrated streams of solar wind can be emitted.

During the most recent solar minimum, which took place from 2006 to 2010, however, several researcher groups noticed 6.7-day and 9-day recurrent changes in geomagnetic activity, and similar patterns in the interplanetary magnetic field, and the solar wind. Using modern data covering the previous two solar minima, these higher-frequency occurrences were judged to be unusual.

Love et al. analyzed historical geomagnetic activity records from 1868 to 2011 and find that the 6.7-day and 9-day recurrent changes were actually unique in the past 140 years.They suggest that the higher-frequency changes in geomagnetic activity are due to an unusual transient asymmetry in the solar dynamo, the turbulent, rotating plasma deep within the sun which generates the magnetic field.

More information: Geomagnetic detection of the sectorial solar magnetic field and the historical peculiarity of minimum 23-24 Geophysical Research Letters, doi:10.1029/2011GL050702 , 2012 

Provided by American Geophysical Union

“Geomagnetic data reveal unusual nature of recent solar minimum.” 

March 19th, 2012. http://www.physorg.com/news/2012-03-geomagnetic-reveal-unusual-nature-solar.html


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