Sunspot numbers and solar flux were down over our reporting week, September 15-21.
Average daily sunspot number was 29.9, down from 50.1 during the previous seven days. Average daily solar flux went down from 88.9 to 83.4.
Geomagnetic indices were up a bit, with average daily planetary A index rising from 6.7 to 8.9, and average daily mid-latitude A index from 6.1 to 7.6. The predicted average planetary A index for the next seven days is expected to rise to 13.1, and average solar flux to 86.4, according to the latest 45-day outlook.
Predicted solar flux is 85 on September 23-24, 90 on September 25-26, 85 on September 27-28, 90 on September 29, 95 on September 30 through October 2, 90 on October 3-6, 85 on October 7-13, 80 on October 14-15, 85 on October 16-20, 88, 90 and 95 on October 21-23, 100 on October 24-27, and 95 on October 28-29.
Predicted planetary A index is 5 on September 23-24, then 8, 18 and 12 on October 25-27, 35 on September 28-29, 32 on September 30, then 30 and 18 on October 1-2, 15 on October 3-5, then 5 on October 6-15, then 18, 20, 12 and 8 on October 16-19, then 5 on October 20-22, then 15 and 10 on October 23-24, and 35 on October 25-27.
Thursday, September 22 was the autumnal equinox, and the first day of the fall season. Around and after the equinox we should observe better propagation than we’ve seen in the past couple of months, and Spaceweather.com reports that this is also the start of the aurora season. Here is an article about aurora in autumn: http://news.spaceweather.com/autumn-is-aurora-season/
Here is a weekly update from OK1MGW.
Geomagnetic activity forecast for the period September 23-October 19, 2016
Geomagnetic field will be:
Quiet on September 23-24 October 6-8, 13-14
Mostly quiet on October 5, 9-10, 12, 15-16, 19
Quiet to unsettled on September 25, 27, October 3-5, 11
Quiet to active on September 26, 28-30, October 1-2, 17-18
Active to disturbed on September (29-30)
Increases of the solar wind from coronal holes are expected on September 25-26, 28-30, October 1-2, 16-18
– Parenthesis means lower probability of activity enhancement.
Petr Kolman, OK1MGW
Czech Propagation Interest Group
Jon Jones, N0JK, of Lawrence, Kansas wrote, “The 2-meter Sprint contest took place September 19/20 Monday evening. A coronal hole solar stream reached the earth and a moderate geomagnetic storm took place with the K index reaching 5. The storm occurred during the 2-meter sprint and many aurora contacts were reported by stations along the northern tier states such as KA0RYT in EN35. The aurora briefly reached Kansas. Around 0220z on September 20 I was working KB0ZOM EN00 on 144.200 MHz via tropo and his CW tone changed to aurora.” (I think this means it got all buzzy and distorted. – K7RA)
Scott Bidstrup, TI3/W7RI wrote: “I don’t know if you’ve seen this, but it could be of some interest to your readers. The Kp index bar chart that we’ve all known and loved since we were all Novices is being replaced by a map that shows the geomagnetic activity in various regions of the world, reflecting the fact that geomagnetic activity is highly variable by latitude and region. It’s not up yet on the SWPC web site, but apparently it’s coming. The article includes a preview sample: http://go.nature.com/2daPSER
“The recent solar activity hasn’t seemed to have improved our propagation much down here in the single-digit latitudes. Six meters has been so dead that everyone is asking why they have bothered setting up 6 meter stations. This should be a busy time of the year for evening TEP into South America from here in the Central American isthmus, but we’re not seeing much of anything at all this season. To be sure we don’t miss any openings no matter how weak, a couple of my friends and I have taken to using JT65, but other than a couple of short and weak Es openings into the Caribbean and Florida, there hasn’t been anything to speak of; very little TEP into South America. We’ve managed a few, weak Es openings into the States – I’ve worked a couple of stations in Arizona and New Mexico on JT65, and of course the usual Florida, but not much else. We had one good opening recently into Cuba and Hispaniola, followed later by Puerto Rico, but a hoped-for contact into HH never did materialize – two stations were on, but I never heard either one. Conditions have been so poor for so long that the joke going around here is that ‘ten meters is the new six.’
“The HF bands have been rather lackluster too. Other than some weak, very sporadic TEP openings into South America on 10 meters, there have been almost no openings on 10, and 12 meters hasn’t been much better, though Phil, TI5/N5BEK, tells me he worked a ZS6 on 10 meters JT65 recently. I’ve had a few contacts into Europe on 15 meters, and some activity into the States, but even 15 meter openings have been getting unreliable for us That’s surprising. Even at the bottom of the last solar cycle, we usually had daily openings on 15 meters here.
“Even 20 meters seems to be affected by all this strange behavior. A daily sked with Jerry, KA7G, in northwestern Montana, has been interesting to watch. Usually, his signal is barely audible at 7AM local time here, but will build slowly to an S9 by 7:30 or 8AM, and then slowly fade again and be all but inaudible by 9AM and through the rest of the day. However, on an increasing number of days it never gets particularly strong.
“Eighty and 40 meters have been interesting, too, in that the refugees from the higher bands seem to be moving onto the low bands. Forty meters has been especially impacted, and the crowding here has been bad enough at times to force some of us into the broadcast portion looking for space where we can find it.
“The odd delayed opening of the lower bands to short skip is continuing. Most of the time, the 80-meter band will open for short skip right at sunrise, and 40 meters will open about a half hour later. Usually, the opening of the band in the morning is remarkably abrupt – short skip will go from near zero to very strong signals over the course of only three or four minutes. The time at which this has been occurring seems to have been quite stable lately. On 80 meters it is nearly right around local sunrise. On days when there is a lot of geomagnetic activity, this transition can happen a few minutes earlier or later, with no real pattern.”
Jan Beaver, KC0V of La Porte, Colorado wrote: “Just a few notes on the much-maligned Cycle 24. Although it clearly was not the equal of its two predecessors in terms of sheer propagation, Cycle 24 has been very good to me. During Cycle 24 I achieved the following milestones from Colorado:
“Five-band WAS (all CW)
“Five-Band DXCC (all CW)
“DXCC on 30, 17, and 12 meters (all CW)
“Pushed my DXCC totals to 271 entities confirmed on LoTW
“2015 ARRL DX CW Rocky Mountain Division Winner (SOLP)
“Cycle 24 offered consistently good conditions on both the high and low HF bands. I did improve my radios and antennas during the run of Cycle 24, although my total station complement is still quite modest by any standard. There were any number of days during Cycle 24 when I made at least one DX contact on every band from 10 through 160 meters (except 60 meters which I do not work). Many contests offered serious action across that same range of radio spectrum, all in a weekend. So as much as I would like to experience a return of the glories of Cycle 22 or whatever, I really have no complaints about Cycle 24.”
Now for a little comic relief, not so much lately but often in the past I would receive emails from people trying to correlate solar activity with all kinds of things, which always seemed to me to be a fool’s errand.
Here is a recent article promoting this theory, for betting on markets: http://bit.ly/2d1FV7n
It is interesting to click on that chart of past solar cycles referenced against economic indicators. When you see it in larger format such as http://bit.ly/2cVyvWC , it looks to me like there is no correlation between low solar activity and economic recessions, or at least the theory seems to have little predictive value.
Speaking of little predictive value, in discussing grand maximums in solar activity, I previously noted that over the past 11,000 years there were 19 grand maximums, such as Cycle 19 in the late 1950s. So, in an attempt to see how rare these are, I did some simple arithmetic and realized that it is rare enough that there is on average about 579 years between these grand maximums. But I should point out that they don’t occur at regular intervals, so projecting forward to the year 2537 AD is meaningless.
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.
Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins.
Sunspot numbers for September 15 through 21 were 12, 13, 14, 47, 56, 32, and 35, with a mean of 29.9. 10.7 cm flux was 84.4, 83.7, 80.3, 83, 82.6, 84.5, and 85.5, with a mean of 83.4. Estimated planetary A indices were 7, 3, 4, 9, 10, 19, and 10, with a mean of 8.9. Estimated mid-latitude A indices were 6, 3, 4, 8, 8, 15, and 9, with a mean of 7.6.