venerdì 11 maggio 2018

The K7RA Solar Update

05/11/2018Sunspots reappeared this week, after none on April 28 through May 3. Average daily sunspot numbers increased from 3.6 (last week) to 14.6 (May 3-9).So far in 2018 56-percent of days were spotless. For all of 2017 the rate was about half or 28-percent, for the whole year, a total of 104 days. These numbers are according to counter-intuitively considering the slight rise in sunspot numbers, yet not unusual, average daily solar flux declined one point from 69.3 to 68.3.Solar activity continues to decline, and we’ve been expecting (over the past few years) solar minimum to arrive about two years from now in 2020.But some have suggested that perhaps the decline is currently faster than anticipated. I like to imagine that a sooner minima could precede a faster rise in the next Cycle! What if the upcoming Cycle 25 echoes Cycle 19? Sorry, no scientific evidence, but I like to dream this could happen.Cycle 19 was the largest in recorded history, and I would be glad to see another one, just so it isn’t accompanied by a Carrington Event. The Carrington Event happened in September 1859 and produced solar flares so powerful that telegraph offices, connected by long lines acting as antennas, caught fire. But the peak of Cycle 19 happened about 100 years reports this week that the American Geophysical Union ( in a paper published May 10, researchers from the University of Birmingham use Extreme Value Theory to estimate the average time between "Carrington-like flares." See is tough to predict, but they estimate one every 100 years. Of course, this means we are long overdue, but perhaps this is like the gambler’s fallacy as it applies to roulette: don’t bet on red just because the last five spins of the wheel landed on black:
According to on page 11, smoothed solar flux numbers around 63 are predicted toward the end of 2019. But when we observe numbers around the last solar minimum (right now I am looking at the 109 days ending on October 9, 2008 as an example) there were numerous consecutive periods of no sunspots (average daily sunspot number during that time was only 1.046) but average daily solar flux was 66.4, several points higher than values predicted for the end of 2019.These long-term predictions are updated about every four weeks, but I have no idea when predictions for 2020 will appear.Predicted solar flux is 69 on May 11-12, 68 on May 13-15, 67 on May 16-18, 72 on May 19-25, 70 on May 26, 68 on May 27 through June 8, and 70 on June 9, 72 on June 10-21, 70 on June 22 and 68 on June 23-24.Predicted planetary A index is 8 on May 11, 5 on May 12-16, 12 on May 17-18, 8 on May 19, 5 on May 20-31, then 18, 25, 20, 16, 12 and 8 on June 1-6, 5 on June 7-12, then 42, 12, and 8 on June 13-15 and 5 on June 16-24.
From Jon Jones, N0JK, on May 5 in a message titled "Six meters comes to life:"  "The summer 2018 sporadic-E season is underway in the northern hemisphere. On May 4 the 50 MHz band was open most of the day across North America and the northern Caribbean. At 1820z May 4, I was able to work K7BHM DM43 AZ from my car on 50.125 MHz during a work break. I was running 10 W on SSB to a 1/4 wave whip and received a 5x5 report. Most of the activity I saw spotted was FT8 on 50.313 MHz, but there was still a lot of legacy SSB activity. The most interesting spots I saw were for the OA4B/b 50.036 MHz beacon. It was spotted along the eastern seaboard as far north as VE2XK in Quebec. At 2043z I saw N5LJL in EM26 spotted it. I listened from my car and had solid copy on the beacon at 2050z! That’s 5,980 km on a mobile whip. The propagation likely multi-hop Es."
Last Friday, Tom Scott, N5GIT, sent this 6-meter report: "Six meters really surprised several of us around here as we were able to copy the TG9ANF beacon in Guatemala. No grid square was copied (I have an audio file). I was using only a long wire antenna tossed over the railing of my second story balcony! I promptly logged XE1AO, in DL89, off that same wire! It sounds like six is off to a great start.”
F.K. Janda, OK1HH of the Czech Propagation Interested Group sends his geomagnetic activity forecast for the period May 11-June 05, 2018"Geomagnetic field will be:Quiet on May 27-29Quiet to unsettled on 14-15, 24, 30,Quiet to active on May 12-13, 19-23, 25, 31,Unsettled to active on May 11, 26, June 3-4Active to disturbed on May 16-18, June 1-2, (5)Solar wind will intensify on May (11,) 17-18, (19-20, 25-27, 31,) June 1-2, (3-4)Remark:- Parenthesis means lower probability of activity enhancement.- Forecasts remain less reliable"
New space weather observations and a video from Dr. Skov."There has been a recent uptick in solar activity over the past few weeks that reminds us how variable Space Weather can be, even near solar minimum. The last two solar storms have brought aurora as far south as Colorado, Indiana, Germany, and the Netherlands. It’s also brought views high in the southern skies over New Zealand and Tasmania.  If these moderately strong solar storms will continue through the next few years as we cross through solar minimum and begin to ascend into the new solar Cycle is yet to be seen. I, for one, hope so.“This week, we have three new bright regions gracing the Earth-facing Sun. One of these regions even launched a solar storm on the Sun's backside. Not bad for a supposedly quiet Sun! This week's forecast highlights these regions and the boost in communications we are enjoying right now on the amateur radio bands. It also highlights some of the amazing aurora photographs reported during the recent solar storm. It shows how active our star can be and just how quickly things can change.“Cheers, Tamitha"See her video at
For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of numbers used in this bulletin, see archive of past propagation bulletins is at More good information and tutorials on propagation are at propagation charts between four USA regions and twelve overseas locations are at for starting or ending email distribution of ARRL bulletins are at numbers for May 3 through 9, 2018 were 0, 13, 14, 14, 14, 25, and 22, with a mean of 14.6. 10.7 cm flux was 66.5, 67.8, 67.6, 67.2, 69.6, 69.6, and 69.6, with a mean of 68.3. Estimated planetary A indices were 4, 4, 20, 31, 17, 14, and 16, with a mean of 15.1. Estimated mid-latitude A indices were 3, 4, 12, 24, 14, 12, and 13, with a mean of 11.7.