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The K7RA Solar Update


No sunspots were observed between March 2 and March 15. One sunspot made a brief appearance on March 2, after a blank sun on March 1. Average daily sunspot number dropped from 1.6 to zero this week, and average daily solar flux rose fractionally from 67.6 to 67.7. We’ll be watching the latest sunspot appearance to see if it is as fleeting as the March 2 sunspot.

Geomagnetic indicators rose slightly, with planetary A index increasing from 5.1 to 7.1, and mid-latitude A index rose from 4.6 to 5.7.

Predicted solar flux is 69 on March 16-23, 72 on March 24-29, 70 on March 30, 68 on March 31 through April 11, 70 on April 12, 72 on April 13-25, 70 on April 26, and 68 on April 27-29.

Predicted planetary A index is 15 on March 16-18, 10 on March 19, 5 on March 20-22, then 8, 5, 8 and 20 on March 23-26, 5 on March 27-29, 8 on March 30-31, 5 on April 1-9, then 8, 10, 14, 16 and 20 on April 10-14, 5 on April 15-16, then 12, 18, 10, 5, 8 and 20 on April 17-22, then 5 on April 23-25, 8 on April 26-27, and 5 on April 28-29.



Carl Luetzelshwab, K9LA, has a comment about solar flux and an observation from N0JK in last week’s bulletin ARLP010:

 “Jon Jones, N0JK said ‘Sometimes the solar flux numbers don't correlate well to the actual ionization.’

 “What Jon said is more the norm than the exception, as solar radiation is not the only factor that contributes to the amount of ionization at any given location. There are two other factors. One is geomagnetic field activity (the K index), which can modify the amount of ionization. The other is an event in the lower atmosphere that couples up to the ionosphere, which also can modify the amount of ionization and which is a very hot topic with researchers nowadays.

“The bottom line is if today's solar flux is higher than yesterday's, it does not necessarily mean that the ionosphere is better today - it could be worse. The result of all of this is that we have monthly median propagation predictions (they are statistical over a month's time frame), not daily propagation predictions.”



This in from Tamitha Skov on early Thursday in a message titled “Solarstorm Mania all over the News:”

“How ironic is it that only one week after I talk about significant advances towards making Space Weather a household name, we get smacked in the face with a bogus story about a massive solar storm threatening to swallow the Earth?  From what I've heard, this story began innocently enough-- someone misread an info-graphic on a Russian space weather website. But then the mistake went viral. Over the past few days, reports spread around the globe, sending people into a panic. I've watched major news agencies publish the story, only to print embarrassing retractions a day later. All of this simply because they ran with a story they did not have the expertise to fact check.  I hate to admit it, but just as I thought we were doing so well, I am reminded of how far we have yet to go.

“This week our Sun is indeed sending us a solar storm, but it’s not all fire and brimstone. It’s the weak, wispy kind we continue to expect as we approach solar minimum. The fact that the storm is weak actually brings us some good news. For amateur radio operators and emergency communicators already wrestling with poor radio propagation conditions on Earth's day side, communications might improve on Earth's night side, especially with auroral propagation. GPS users should also enjoy the quiet conditions, but be aware for glitches, especially after sunset and at higher latitudes where aurora is active. As for aurora sightings during this weak storm, reports are coming in from Norway, Sweden, and Finland as well as from Ontario, Manitoba, and Saskatchewan Canada. In the U.S.A. aurora has been sighted as far south as Michigan and Minnesota.

“While these solar storm effects are surely noteworthy, they are hardly catastrophic or even massive. So as far as all the hype?  I think we can safely put that story to bed.”



Geomagnetic activity forecast for the period March 16 to Apr 10, 2018 from F.K. Janda, OK1HH.

 "Geomagnetic field will be:

Quiet on March 20, 24, 28-29, April 1-2, 4-9

Mostly quiet on March 21, 30-31, April 3

Quiet to unsettled on March 19, 22-23, 25, 27

Quiet to active on March 16-18

Active to disturbed on March 26

Solar wind will intensify on March 16-18, (19-20, 25-26, April 3-?).


- Parenthesis means lower probability of activity enhancement."



This is from Jeff, N8II, from West Virginia on March 15: "There probably are a record number of DXpeditions to the ‘Ts’ and other countries from Africa, so named because several of the African countries that begin with T (former French) were some of the rarest countries.

“Today on 15 meters TN5R in the Congo Republic, TY7C in Benin, and TJ2TT in Cameroon were all operating 15-meter phone at the same time as were the returning Lithuanians on Annobon Island, 3C0W. I worked Annobon, failed to get Cameroon, and had already worked the other two. In addition, on 15-meter phone were 5V7SM in Togo (worked) and 9X9PS from Rwanda. That’s quite a line up!

“At times, signals from Africa have been totally unreadable or very weak on 15-meters, but the solar wind picked up today raising the MUF despite nearly identical SFI (69 today) compared to other days this week.

“Also, an expedition to PJ5 that was unreadable on 15-meter CW the past 2 days, was S9 at 1400Z today. The best signals for the most part from Africa were in the 1400Z hour also, except for Annobon who was louder around 1600Z. I have logged the Benin and Congo groups on several bands, including 80 meters, but the MUF has been too low to hear any of them on 12 or 10 meters. The only rare DX worked this week on 12 meters was XR0YD on Easter Island, on CW, who has also been logged on 80 through 15 meters.

“Conditions on 80 meters are considerably worse than in December and January, but good enough to still work some of the DXpeditions. Signals on 160 meters have been very weak, but 40 and 30 meters have improved as the nighttime MUF has risen due to seasonal changes. I finally logged Annobon on 30 meters today after quite a bit of calling during which they were good copy to loud, but running many Japanese and European stations. I would guess their 30-meter JA/USA QSO ratio was at least 25 to 1 up until today when they were S9 at 2000Z (my sunset is 2318Z), which was louder than yesterday. So, obviously, they had a very good path to Japan for several hours, from before the Japanese sunrise until way after their local sunrise in Europe.

“Twenty meters continues to be my best band for DX by far. For example, I logged A5A in Bhutan around 1500Z on CW today. Signals from Europe are generally moderate to loud all morning long and southwestern Europe stays in to about 2200Z on good days. The morning short path to Australia appears to be closed or very marginal most days. Seventeen meters is often usable to Europe and the Middle East at around 1400-1700Z, but signals are weaker and often exclude northern and eastern Europe."



Mark Lunday, WD4ELG in Greensboro, North Carolina has sent some interesting reports on his experiments with QRSS mode. What is QRSS? It is extremely slow speed CW, so slow that a single dit may last for 60 seconds. Using a computer sound card and special QRSS software, stations running power levels as low as 10 microwatts can be extracted out of the noise.

See: and



For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of numbers used in this bulletin, see

An archive of past propagation bulletins is at More good information and tutorials on propagation are at

Monthly propagation charts between four USA regions and twelve overseas locations are at

Instructions for starting or ending email distribution of ARRL bulletins are at

Sunspot numbers for March 8 through 14, 2018 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 66.6, 67.5, 67.7, 67.8, 68.1, 68.6, and 67.7, with a mean of 67.7. Estimated planetary A indices were 4, 12, 12, 6, 3, 4, and 9, with a mean of 7.1. Estimated mid-latitude A indices were 3, 10, 9, 7, 2, 3, and 6, with a mean of 5.7.





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