[SFDXA] The K7RA Solar Update

Fri Jun 20 07:27:01 EDT 2014

    The K7RA Solar Update

06/20/2014

The daily sunspot number rose dramatically this week on June 13 when it 
increased to 276, but two days later it was back below 100. The 
resulting weekly average for June 12-18 (141) was actually down 2.3 
points from the previous seven days. Average daily solar flux was down 
11.7 points to 134.7.

Predicted solar flux has weakened lately, and for the near term flux 
values are predicted at 105 on June 20-22, 100 on June 23-24, back to 
105 on June 25-27, 120 on June 28 through July 6, 115 on July 7-12, and 
peaking at 130 on July 13-19. ARRL Field Day is June 28-29, when 
predicted flux values are 120. This is the highest predicted flux value 
for those two days since May 25, when it was also 120.

Predicted planetary A index is 5 on June 20-21, 8 on June 22, 5 on June 
23-25, 8 on June 26, 5 on June 27 through July 10, 8 on July 11, 5 on 
July 12, then 10, 8, 8 on July 13-15, 5 on July 16-21 and 8 on July 22-23.

OK1HH predicts geomagnetic conditions will be quiet to unsettled June 
20, mostly quiet June 21, quiet to unsettled June 22, mostly quiet June 
23, quiet to unsettled June 24-25, quiet to active June 26, active to 
disturbed June 27, quiet June 28-30, quiet to active July 1, quiet July 
2-3, mostly quiet July 4-5, active to disturbed July 6, quiet to active 
July 7-8, quiet July 9, mostly quiet July 10, quiet to unsettled July 
11, quiet July 12, quiet to unsettled July 13, quiet to active July 
14-15, and active to disturbed July 16.

Scott Bidstrup, TI3/W7RI, shared an article from Scientific American by 
Clara Moskowitz, positing that perhaps the current solar cycle is not so 
terribly weak, but that we've become accustomed to stronger cycles in 
the second half of the twentieth century.

*http://www.scientificamerican.com/podcast/episode/strange-solar-cycle/*

Scott also shared some observations on June 16 about recent on-air 
conditions from his location in Costa Rica. Scott writes, "Sadly, 
propagation here in the low latitudes has really been in the doldrums 
over the last week or so. Ten meters has barely been open on the good 
days, and so little PSK activity, I've given up on it on ten and have 
been spending more time on 15 and even 20 lately - conditions not unlike 
the last solar minimum. Even the 10 meter FM repeaters, normally a daily 
phenomenon here, have been weak or absent. On looking at the data this 
morning, I see the 304a index is declining again, back down to only 14 
points above the typical solar minimum. Except for two small regions, as 
I write this, there's nothing at all on the STEREO B image showing 
what's about to rotate into view on the solar disk.

"The lower solar activity has greatly improved gray line DXing on 75 
meters, though, and HP3AK and W9UCW have been having a grand time 
working VKs, ZLs and the odd JA now and again every morning at their 
local sunrise - for about the last week, the best DXing conditions in a 
really long time. Sadly, the atmospheric noise has been pretty high 
lately too, approaching the seasonal maximum here, so that's tempered 
the fun a bit. HP3AK did manage to complete a contact with a VK on 160m, 
about a week ago.

"Six meters has been all but dead since I last wrote; one brief opening 
between Costa Rica and the Leeward Islands several days ago, and that's 
been about it - KP4EIT was heard for about 20 minutes and an HI8 beacon 
for about half an hour, neither were ever strong enough to work. I did 
hear some mixed SSB on 50.110 for about a minute once last week. That's 
been about it. It's all been frustrating enough to make me want to go to 
work on that EME array I've been threatening for years."

Scott mentioned the 304a index, which is referenced on Scott's page at 
*http://www.bidstrup.com/w7ri-hf-radio-propagation.htm*. "The 304A Index 
is the relative strength of total solar ultraviolet radiation at a 
wavelength of 304 angstroms, emitted primarily by ionized helium in the 
sun's photosphere. It is solar radiation in this frequency band that is 
directly responsible for about half of all the ionization of the F2 
layer, the ionosphere layer of greatest significance to us." (paraphrased).

Ted Leaf notes that his call sign is K6HI, not K8HI as reported in last 
week's bulletin. I thought I'd messed up, but then noted that the email 
I was referencing was signed K8HI. At any rate, he is on the west coast 
of Hawaii, the Big Island, and not to be confused with KH6HI, who is on 
Oahu, also in the state of Hawaii.

This weekend is the All Asian DX CW Contest. For details, see 
*https://www.jarl.org/English/4_Library/A-4-3_Contests/2014AA_rule.htm*.

And of course, ARRL Field Day, easily the most popular on-air activity, 
is next weekend!

For more information concerning radio propagation, see the ARRL 
Technical Information Service at 
*http://arrl.org/propagation-of-rf-signals*. For an explanation of the 
numbers used in this bulletin, see 
*http://arrl.org/the-sun-the-earth-the-ionosphere*. An archive of past 
propagation bulletins is at 
*http://arrl.org/w1aw-bulletins-archive-propagation*. More good 
information and tutorials on propagation are at *http://k9la.us/*.

Monthly propagation charts between four USA regions and twelve overseas 
locations are at *http://arrl.org/propagation* 
<http://arrl.org/propagation-of-rf-signals>.

Instructions for starting or ending email distribution of ARRL bulletins 
are at *http://arrl.org/bulletins*.

Sunspot numbers for June 12 through 18 were 196, 276, 159, 80, 81, 87, 
and 108, with a mean of 141. 10.7 cm flux was 174.5, 152.7, 143.5, 
130.2, 116.8, 114.3, and 110.8, with a mean of 134.7. Estimated 
planetary A indices were 4, 5, 8, 5, 5, 8, and 16, with a mean of 7.3. Est