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The following is the weekly propagation bulletin from W1AW / ARRL (posting on 20170331 22:40 UTC):
QST de W1AW
Propagation Forecast Bulletin 13 ARLP013
From Tad Cook, K7RA Seattle, WA March 31, 2017 To all radio amateurs
SB PROP ARL ARLP013 ARLP013 Propagation de K7RA
Solar activity rose over the past week, with average daily sunspot numbers rising from 3.4 to 29.7 and solar flux from 71.2 to 77.9.
Average daily planetary A index increased from 10 to 18.3, and average mid-latitude A index went from 7.1 to 13.6.
Predicted solar flux is 86, 87 and 88 on March 31 til April 2, then 86, 84, 83 and 82 on April 3 to 6, 71 on April 7 to 14, 73 on April 15 to 17, 75 on April 18 to 22, 78 on April 23 to 26, 75 on April 27 to 29, 73 on April 30 to May 1 and 71 on May 2 to 11.
Predicted planetary A index is 20 on March 31 through April 2, 15 on April 3 and 4, 12 on April 5 and 6, 5 on April 7 to 16, then 24, 25 and 10 on April 17 to 19, 5 on April 20 to 22, then 25, 40, 35, 20, 18 and 12 on April 23 to 28, and 8, 16, 12, 15 and 12 on April 29 through May 3, followed by 5 on May 4 to 13 and 24 on May 14.
F.K. Janda, OK1HH sent us his geomagnetic activity forecast for the period March 31 to April 25, 2017.
‘Geomagnetic field will be: quiet on April 9 and 10, 14 to 16, 20 to 22 mostly quiet on April 6, 8, 11 quiet to unsettled April 4, 12 and 13, 19 quiet to active on April 3, 5, 7, 23, 25 active to disturbed on March 31, April 1 and 2, 17 and 18, 24
Amplifications of the solar wind from coronal holes are expected on March 31, April 1 to 4, (5 to 8,) 12 and 13, (14,) 16 to 20, 25.
Remark: - Parenthesis means lower probability of activity enhancement and/or lower reliability of prediction.’
Tamitha Skov released a space weather video last week:
Jon Jones, N0JK reported: 'Aurora contacts reported on 6 meters March 27 along the northern tier states and Canada. This was due to a G2 geomagnetic storm from coronal wind stream.’
Scott Bidstrup, TI3/W7RI sent this from Costa Rica:
'Don’t know if you’ve seen this, but a magnetic precursor event to solar flares has been discovered, that may actually lead to short-term warnings before a flare occurs.
The six meter drought that everyone has been complaining about up there has been even worse for us down here in the single-digit latitudes. It’s been at least six months since I’ve logged a six meter QSO. In the wake of coronal hole passages, there have been a couple of evenings recently with some very modest TEP openings from here into Brazil and Argentina, but with only a small handful of stations heard weakly and no new stations not already worked many times. There has been no sporadic E at all for many months - not even hearing the beacons from Venezuela and French Guiana that indicate our most common openings to the east. If there is supposed to be an inverse correlation between solar activity and sporadic E, like the textbooks claim, you could have sure fooled me.
Not that there has been no sporadic E at all; indeed, there has been very frequent Sporadic E openings into South America on 10m in the daytime here, and even frequent evening TEP openings into South America on 10m as well. But the signals are about what we would normally expect on six meter openings rather than ten. MUFs from these events just aren’t getting very far into the VHF. Conventional F2 openings on ten have become very rare now.
Other propagation on the upper HF bands has been poor - the declining solar activity has taken a big toll here on the upper HF bands, with most band openings starting later in the morning than in the past, and ending earlier in the late afternoon - and signals not being particularly strong when the band is open. The only saving grace has been that our mid-day break has been shorter and weaker than at the solar maximum, so it’s often possible to hear signals and even work them at midday on 20m, which has not been possible at higher sunspot numbers. MUF has gotten high enough to open 17m on most days, but often it doesn’t quite make it to 15m. So when 15m is open, it’s often the result of a weak sporadic E event or the aftermath of a coronal hole passage. During the last solar minimum, 15m would be open most days, but so far during this one, it’s been hit and miss at best. And the solar minimum is just getting a good start.
30m has been the most reliable performer - almost always open into the States during the day and worldwide at night. Sadly, PSK activity seems to have declined on 30m, so I haven’t worked as many stations with the ragchews I dearly love, just the spartan JT9 contacts. Sure wish we had phone privileges on that band.
40m has been seeing a huge increase in QSO activity with conditions on 20m declining. There are evenings now where finding an open spot can be a bit of a problem. Most of what I hear on phone here is the States, but I am seeing a lot of eastern European DX on PSK, and my good friend, Michael, TI7XP, has worked some pretty good DX on 40m CW in recent days, including Kuwait and several stations in the Far East, and a lot of VK/ZL. The DX here is definitely improving on 40m.
60m is still not available here, and all of us here are holding our breath, waiting for a response from the FCC on the League’s petition for rulemaking, allowing 100w. activity up there on the new WARC 60m band. If it happens for the States, it would be terrific news for us - another piece of terrific ammunition in our fight to get access to 60m here. There are still no Central American countries that allow access to 60m yet. And I can’t see a good reason why not - there is almost no local commercial or government activity in that portion of the spectrum here.
80m is seeing an improvement, especially in DX as the solar activity declines. My good friend in Panama, Jay, HP3AK, is working Japan on most morning greylines, and often getting quite good reports. VK/ZL is being worked more frequently, too - often several times per week. And nighttime Old World DX is more frequently heard now than it was just a year ago. Several of my local friends report working Europe with fairly modest 80m installations. Signal levels from the States’ 75m evening ragchews have been noticeably stronger than in the past, too. Nighttime D-layer hasn’t responded as much to the rising cosmic ray flux as I would have expected by now.
Noise levels on 160m have been low enough this winter that some of the locals are getting more interested in top band. TI7XP has a new skywire loop up for that band, and has worked some good DX on it. But the summer noise season is just about here, and I don’t expect the interest will last long.
And finally, I am pleased to report that I have copied four experimental beacons on 630m from the States, and have sent the corresponding WSPR decodes to the operators, who were delighted for the reports from here. Most nights, when noise levels aren’t particularly high, I can hear at least one or two, with just a G5RV at 50 feet and an ordinary IC7200 tuned to the appropriate frequency. Enough success to demonstrate that QSOs with Central America from the States should be possible with modest stations on that band. Not much hope for 630m access here though, at least until it has become a major band in the States like it now is in Europe, so we can justify access to it here. I have checked the 2190 band, but so far, I haven’t copied anything yet.’
For more information concerning radio propagation, see the ARRL Technical Information Service at http://ift.tt/1bXLmvi. For an explanation of numbers used in this bulletin, see http://ift.tt/1bXLlHQ.
An archive of past propagation bulletins is at http://ift.tt/1bXLlHS. 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://ift.tt/1cYhR1b.
Instructions for starting or ending email distribution of ARRL bulletins are at http://ift.tt/1cYhR1d.
Sunspot numbers for March 23 through 29, 2017 were 12, 12, 11, 20, 49, 51, and 53, with a mean of 29.7. 10.7 cm flux was 72, 72.3, 74, 77.2, 82.8, 83.7, and 83.3, with a mean of 77.9. Estimated planetary A indices were 11, 6, 4, 4, 54, 28, and 21, with a mean of 18.3. Estimated mid-latitude A indices were 9, 7, 3, 3, 34, 22, and 17, with a mean of 13.6.
Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g
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