The K7RA Solar Update


Most stations reported not-so-great conditions for ARRL Field Day last weekend, but there were sporadic-E openings on 6 and 10 meters. Geomagnetic conditions were a bit rough, with the Planetary A index in double digits for both days, June 26-27. Conditions at mid-latitude were not too bad, but in Alaska, the College A index was 20 and 22. With atmospheric noise from seasonal thunderstorms, it was a bit rough at times, although with Field Day, just about everyone has fun. Read comments from participants and select 2010 “ARRL Field Day” from the drop-down menu.

Sunspot numbers for June 24-30 were 13, 12, 0, 11, 11, 24 and 11, with a mean of 11.7. The 10.7 cm flux was 74.4, 74.5, 74.5, 72.9, 73.9, 73.6 and 73.8, with a mean of 73.9. The estimated planetary A indices were 7, 8, 15, 13, 7, 11 and 19, with a mean of 11.4. The estimated mid-latitude A indices were 5, 8, 9, 12, 6, 8 and 15, with a mean of 9.

June is over, so we have some new averages for sunspot numbers, and the numbers declined slightly. The average daily sunspot number for the month of June was 18, down from 20 in May. The three-month average centered on May was 16.2, down from 18.5 the previous month (centered on April, with data from March through May), 22.3 the month before and 25.7 the month prior to that (centered on February). For the past week, average daily sunspot numbers were 11.7, down from 16.1 the prior week and 26.9 before that.

The latest prediction (from Thursday afternoon) via USAF and NOAA has solar flux at 72 for July 2-3 and 74 on July 4-10. The same forecast has planetary A index at 10 for July 2, 8 on July 3-4 and 5 on July 5-10. Geophysical Institute Prague in the Czech Republic sees quiet to unsettled conditions July 2-3 and quiet conditions July 4-8.

With sporadic-e season in full swing, we’ve heard a number of 6 meter reports.

Jim O’Brien, W4AMP, of Cedartown, Georgia (EM74) reports that on June 19, 6 meters was open most of the day. With a 2-element beam and 100 W at midnight local time (0400), he worked VE7BEE in DN09 and KW7Y in CN88. He noted that midnight is an odd time for multiple-hop sporadic-E skip.

Martin McCormick, WB5AGZ, in Stillwater, Oklahoma sent in this note about sporadic-E on Field Day: “On Saturday June 26, I was tuning between 25 and 30 MHz at about 12:30 CDT and heard a narrow-band FM signal on 25.99 MHz playing music. It was a broadcast station’s queuing system. These used to be very common around 26.xx MHz, but most stations have gone to much higher frequencies to get away from sporadic-E, F2 and illegal CB-type activity, so when one hears one of these signals these days, it is rare.

“I listened for a while and heard two IDs, which turned out to be for KSCS, whose actual broadcast frequency is 96.3 in Fort Worth, Texas. This is very interesting because Stillwater, Oklahoma is only a bit more than 200 to 250 miles from the Dallas-Fort Worth area. The signal was full-quieting with fades for several minutes and then it vanished very quickly. This should have been good for Field Day participants on 12 and 10 meters, as E-skip doesn’t usually get that short.

“The bands were actually pretty boring with 6 meters dead from here and not many strong signals between 25 and 30 MHz. You’d be surprised what the letters KSCS can sound like, even when heard fairly clearly. I made a recording of the audio and heard them refer to Texas, but it took several runs at to find anything that made sense. Fortunately, Radio Locator lists stations by call letters, frequency and program format. KSCS is in Texas, plays country music and is on 96.3 MHz. Some radio stations may still use these frequencies for actual remote broadcasts from a truck or public building back to the studio, so you never know what you will find.”

Jeff Hartley, N8II, of Shepherdstown, West Virginia, sent this report: “The good news is the almost ever present E-s to fill in gaps left by low solar flux. Several times on 15 meters, I have heard Spain and Italy past midnight local in Europe. Saturday June 12, was fabulous with a good European opening on 10 meters from around 1320-1430; a couple of signals were over S9 from Wales and Germany and about 25 stations were worked mostly in southwest and southern Europe.

“On Saturday June 19 at 1630, I was operating in the West Virginia QSO Party. I was able to work the ‘far side’ of West Virginia during several periods on 20 meters as close as about 200 miles away. I had almost continuous openings to 8s, 9s and close-in 4s, as well as long openings to New England. There was also a very extensive double hop 10 meter opening to the Rockies, Southwest, and West Coast from 2100 through past 0200 that also extended to 6 meters. I worked about 720 stations on 20 meter phone and 170 on 10 meter phone. I missed Alaska and Vermont for Worked All States, but several called in from Hawaii on 20 meters, including KH6G mid-day mid-path. Sunday, June 20 around 1300, I heard N0KE and K0GU in Colorado and others out west calling CQ DX. I heard locals calling a few Europeans that were in the noise here without much success. WQ7Y was very loud from Northwest Washington here just past 6 AM PDT.”

Jon Jones, N0JK, of Wichita, Kansas reports: “Kind of an unusual Es contact on 6 meters last Sunday, June 27. I worked HC1HC Ecuador at 2345. He was in for about 20 minutes, peaked up to 599 at times. This is the first time I have heard or worked Ecuador on 6 meters via Es. I have worked it a number of times on F2 during both Solar Cycles 22 and 23 peaks. Suspect it was Es rather than F2, as the solar flux was 75. Kp did reach 3, probably just enough to dampen northern Es paths and perhaps enhance Es closer to the equator. HC1HC is about 4664 km from EM18 -- two hops of 2332 km each?” Jon was using CW, by the way.

All times listed are UTC, unless otherwise noted.

Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears each Thursday in The ARRL Letter. You can find a guide to articles and programs concerning propagation here. Check here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.