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The K7RA Solar Update


Solar indicators continue to weaken. Average daily sunspot numbers declined from 129.4 to 103.3, and average daily solar flux went from 128.5 to 110.3. This is comparing data from May 22-28 to the previous seven days.

The instruments used to measure solar flux at the observatory in British Columbia were overloaded on May 24, and the estimated solar flux was 118. The actual measured value was 124.5. Something went wrong at the Fredericksburg, Virginia magnetometer which supplies our mid-latitude magnetic K and A indices, so there is no data for May 24-27. The mid-latitude A index numbers for those dates that appear at the end of today’s bulletin are also estimates, but they are my own.

The predicted solar flux values for Field Day weekend, Friday through Sunday, June 27-29 have also been on the decline. On May 15 the prediction was 125, 135 and 135. Then on May 19 they were adjusted down to 120 for all three days, and on May 26 the estimate declined again, to 108, 108 and 110, where they remain today. Field Day does not begin until Saturday, June 28, but it is useful to see the prediction for the day before.

The latest prediction has solar flux at 105 on May 30-31, 100 on June 1-3, 95 on June 4-5, 105 on June 6, 120 on June 7-8, 125 on June 9-11, 120 on June 12-13, 115 on June 14, 110 on June 15-25, 108 on June 26-28, 110 on June 29-30, 115 on July 1-2 and 120 on July 3-5.

Predicted planetary A index is 5 on May 30-31, 8 on June 1, 5 on June 2, 8 on June 3-4, 5 on June 5, then 8, 10 and 8 on June 6-8, 5 on June 9-30, then 8 on July 1-3 and 10 on July 4.

OK1HH provides us with his weekly geomagnetic outlook which predicts quiet to active conditions May 30, quiet to unsettled May 31, mostly quiet June 1, quiet June 2, quiet to active June 3, mostly quiet June 4-5, active to disturbed June 6, quiet to unsettled June 7, quiet on June 8, mostly quiet June 9-10, quiet to unsettled June 11, quiet on June 12, mostly quiet June 13, quiet on June 14-17, quiet to active June 18-19, and quiet on June 20-24.

On May 24, Jon Jones, N0JK wrote: “Back in 2013, on May 9 was a major 6 meter Es to TEP opening to South America from the Midwest and Alberta, Canada to South America. It happened again on May 24, 2014.

“The band opened via Es linking to TEP on to South America starting around 2050z May 24. Here in eastern Kansas, LU1FP FF99, LU1FAM and LU5FF FF97 were peaking 20 over S-9 on my attic M2 HO loop antenna at around 2120z. The opening lasted until about 2230z.

“I logged PP5XX, PY1RO, LU1FP, LU5FF, LU1FAM, PY2HN and PY2XB. Other stations were spotting/working CE and CX, but I did not hear them. The opening extended north to W7GJ MT, VE7SL BC, VE5UF SK and NT0V ND. CE3SX worked NT0V to complete the 48 continental states on 6 meters. LU5FF worked VE7SL in BC at 2212z.”

Jim Henderson, KF7E, wrote on May 28: “The current SFI has dropped to 99. It was approx 160 just 2 weeks ago, and 184 on 4/16. I think the last time it was this low was mid September 2013. A substantial dip, and worth watching.”

Yes, almost frightening, isn’t it? However I am happy to report that after a solar flux reading of 99.4 on May 28, it rose to 102.7 on May 29. In other news of declining solar numbers, the daily sunspot numbers on May 26-29 were 110, 96, 72 and 55.

Carl Zelich, AA4MI, of Chuluota, Florida wrote: “Last weekend was the CQ World Wide WPX Contest (CW). Not being a contester, I decided to explore the WARC bands.

“Activity was extremely quiet; you could count the number of stations on one hand. And the SFI at 118 with a K at 1. Nevertheless I heard a very, very weak CW signal! Further investigation revealed FW5JJ in Wallis and Futuna! A few RST exchanges and a short QSO on 18.082 MHz on May 24 at 2156 UTC.”

Here is what running the numbers for that day on W6ELprop revealed. Looks like the band would open around 1800 UTC on 18.1 MHz and after 2330 UTC, signal strength should improve, reaching a peak around 0500-0600 UTC. There is another much shorter opening around 1100-1230 UTC.

Carl is correct. The band sounds dead if nobody is transmitting. Of course the band may have sounded dead because so many were in the contest.

Max White, M0VNG, sent along an article about the basics of HF propagation, written by G3XTT:

Dennis Egan, W1UE/HR9, wrote about a six meter opening to Honduras: “I'm here on Roatan Island, NA057 grid EK66 for the week. I saw some activity on 6 meters on the cluster, so on a lark I tuned up to the band. Station here isn't much, a barefoot K3, 90 feet of LMR240 coax, and a G5RV antenna up 15 feet. To get any power out, I had to use the K3 internal tuner, so if one does the math I probably had less than 20w at the antenna. So, I wasn't expecting much.

“I heard KP4KD/4, he was loud, so I gave him a call. One call, one Q. Over the next several hours I worked 45 stations, from VY2ZM (FN86) to W7DN (CN95). While most of the stations were in the EM grids, it was still exciting. Last station worked was N5DG, at 0017Z on May 27.”

Laurence, GJ3RAX, from Jersey sent a nice clarification about his QTH and its relation to the British Isle. Last week I said Jersey is part of the UK, and it is not. “I feel the need to give you a correction to your latest news report. The island of Jersey is not in the United Kingdom. We are self governing for all internal matters, but external matters are administered from the UK. Our taxes are set locally and are different to those in the UK. A rather inexact analogy could be the relationship between Puerto Rico and the USA as PR is not a state but the licenses are administered by the FCC in the USA. I usually say that where I live is the real Jersey as opposed to the new one that was founded in 1664 by Sir George Carteret who was from Jersey.

“Great Britain is G, GW and GM. The UK is Great Britain and Northern Ireland, GI. The British Isles consist of the UK plus GJ, GU, GD and EI and so is a geographic definition rather than political. The British Islands are all those with a G series prefix (and the new ones starting with M or 2) and does not include EI.”

On May 29, GJ3RAX wrote: “I have had some more nice QSOs on 6 meters this week during the Es openings. Last year I had a total of 39 countries and 106 grid squares worked on that band. This year I am already up to 27 countries and 58 grid squares so I am on track to do better than last year and I have still not yet improved my antenna system.

“On Tuesday my only DX was down to EA9 again. On Wednesday it was better with QSOs to YL, DL, OK, SP, OE and 9A. Some of them were indicating well over 30 dB over S9 until the opening suddenly closed and I was able to relax again.

“Today I have had no QSOs on 6 meters and only heard a couple of very weak stations, identifying only one callsign which was EC5CIA who was way down, but 5x9 each way a week ago. Today it sounded more like a meteor ping as he soon vanished and did not emerge again from the noise.

“Later this morning I felt masochistic so I went on 40 meters with QRP running my IC-703 which usually gets me reports that are as good as running 100 watts from my IC-756 Pro 2. I got the IC-703 a couple of weeks ago for use as a transverter driver but it is fun using as it is on HF. I don't tell them that I am only running 10 watts out until I have been given a report and they are usually surprised when I tell them what I am using. It is great pity that the IC-703 is no longer in production. The only modern comparable radio for QRP is the KX3 and that is a lot more expensive over here.

“What has surprised me recently is that when there is Es on 6 meters I assume that I should also be hearing more of it on 10 meters, but I often find that band is very quiet when 6 meters is wide open.”

For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of the 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 May 22 through 28 were 70, 112, 130, 133, 110, 96, and 72, with a mean of 103.3. 10.7 cm flux was 111.3, 116.3, 118, 113, 108.2, 105.9, and 99.4, with a mean of 110.3. Estimated planetary A indices were 9, 19, 6, 4, 4, 4, and 4, with a mean of 7.1. Estimated mid-latitude A indices were 9, 17, 6, 4, 4, 4, and 5, with a mean of 7.





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