The K7RA Solar Update


Sunspot activity rose this week, with the average daily sunspot numbers up more than 45 points to 97, while the average daily solar flux rose more than 24 points to 129.2. Sunspot numbers for October 11-17 were 82, 89, 85, 97, 119, 107 and 100, with a mean of 97. The 10.7 cm flux was 116.6, 121.9, 124.9, 132.1, 136.8, 137 and 135, with a mean of 129.2. The estimated planetary A indices were 6, 12, 38, 19, 8, 5 and 7, with a mean of 13.6. The estimated mid-latitude A indices were 5, 12, 28, 20, 7, 5 and 6, with a mean of 11.9.

We saw high geomagnetic activity on October 12-14, with the planetary A index at 12, 38 and 19, the college A index (in Alaska) at 18, 70 and 33 and the mid-latitude A index (measured in Virginia) at 12, 28 and 20. On October 13, a solar wind spilled through a gap in the Earth’s magnetosphere, making for unsettled conditions, and aurora were seen across the northern tier states in the US.

The latest prediction is for the solar flux to peak at 135 (not at 150 as predicted earlier and not 135 as reported in The ARRL Letter for October 18) for October 19-21, 135 and 130 on October 22-23, 125 on October 24-26, 130 on October 27-28, then down to 125, 120, 115, 110, 105 and 100 for October 29-November 3, and then 105 on November 4-5, peaking again at 140 on November 12-14. The predicted planetary A index is 6 on October 19, 5 and 8 on October 20-21, 5 on October 22-November 7, then 10, 20, 15, 12, 8, 8, 10 and 8 on November 8-15, and down to 5 again on November 16 through the end of November

In last week’s Solar Update, we mentioned John King, EI2HVB, of Letterkenny, Ireland. This week he gave a little more detail. He worked W1AW at 1927 UTC on October 10 on 20 meters CW, running 2 W. This week he wrote: “I have a sloping V dipole, the front plane of which is firing due east, and the best DX to the east so far is a 559 into Perm in Eastern Russia (2000 miles from my station). I regularly get anywhere from 579-599 all over Eastern Europe. I cannot seem to work Spain, Portugal or North Africa, so there is no side lobe to the south of my antenna; however, there seems to be a side lobe firing north, as I recently got a 589 into Iceland. On October 10, when I worked W1AW, the Northern Lights were seen from the north of Ireland later that night, and they had also been visible the previous night. I suspect my signal was going over the North Pole rather than across the Atlantic.”

Of course, without a directional antenna, it is difficult to know, although we can assume W1AW was using a directional antenna from their end. Following last week’s Solar Update, Jim Parkinson, W9JEF, of Tontitown, Arkansas, commented: “When we talk about radio propagation, most of us assume the path to be a straight line (in azimuth). But according QST articles by Eric Nichols, KL7AJ, that path is not always ‘straight.’ As Eric points out -- and many other hams such as myself have experienced -- the aurora and other polar effects can bend or reflect a signal. Assuming that the ‘straight’ path did not exist at the time, would the portion of signal from John’s dipole that reached the aurora region not have been bent back eastward toward W1AW (with reciprocity)?”

By the way, a little point of interest: Jim’s aunt, Ethelyn Parkinson, wrote the 1968 book Today I am a Ham.

John Jones, N0JK, of Wichita, Kansas, wrote: “There was a nice ‘off-season’ October E-skip opening on 50 MHz on Sunday, October 14. The band appeared to be open more than six hours for many across the Eastern US to the Midwest and Southern Canada. Here in Kansas, the W3HH/b EL89 (3.25 W, omni antenna) and the W4CHA/b EL88 6 meter beacons were solid copy on my attic dipole around 0315 UTC October 15.”

Joe Dawson, K4WLS, of Atlanta, Georgia wrote on October 18: “I have made contacts in France, Belgium, Latvia, Greece, Croatia, Morocco, Mexico, Cuba, Cayman Islands and Italy in the past three days during my lunch hour using a slinky antenna and 50 W on 10 meters. I’ve had similar DX activity on 15 and 17 meters as well, but not to the extent of 10 meters. The barn door is open on 10 meters during the day, but shuts down cold around 5 PM here.”

Thanks Joe! And thanks for mentioning the slinky antenna, which I have not heard of for a long time. A web search though shows there is still quite a bit of interest in this antenna.

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 and 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.