Register Account

Login Help


The K7RA Solar Update


No new sunspot activity this week, and no emerging sunspots are visible on the far side of the Sun. Sunspot region 1025 (or 11025) that appeared over August 31 and September 1 faded more than a week ago, and the area in which it appeared has just rotated over the Sun's western limb.

Sunspot numbers for September 3-9 were 0, 0, 0, 0, 0, 0, and 0 with a mean of 0. The 10.7 cm flux was 68.6, 68.4, 68.5, 69.2, 68.8, 68.9 and 69.2 with a mean of 68.8. The estimated planetary A indices were 4, 5, 2, 3, 3, 2 and 1 with a mean of 2.9. The estimated mid-latitude A indices were 4, 4, 2, 2, 3, 2 and 3 with a mean of 2.9. The average daily solar flux for this week was up slightly, just 0.7 points, to 68.8. Geomagnetic A indices were quieter, with last week's average daily planetary and mid-latitude A index at 5.7 and 4.1 respectively, while both numbers dropped to 2.9 for this week.

Very quiet and stable geomagnetic conditions were observed by the magnetometer used to generate the College A Index at Fairbanks, Alaska on September 9-10. From the last reading on September 8 through the end of the UTC day on September 10, the K index was zero at every 3-hour reading. It may have continued at that zero-level, but as of early Friday we have only the data for Thursday. You can see it here. For a longer range view, check here. The planetary A index is projected to be 5 for today through September 14, then 8 for September 15-18. Solar flux is expected to be 69 for today and tomorrow, then 68 for September 13-19. Geophysical Institute Prague predicts quiet conditions for September 11-12, quiet to unsettled on September 13, 15 and 17 and unsettled on September 14 and 16. But Petr Kolman, OK1MGW, of the Czech Propagation Interest Group thinks that September 14 will be quiet, but September 16 and 26 will be unsettled to active.

When the term "UTC day" is used in this bulletin, it refers to the date which ended after 2359 UTC. When it is 2359 UTC (the same as Greenwich Mean Time, or GMT), Alaska Daylight Savings Time is 1559; 1600 local Alaska time is in the following UTC day, because it is after midnight in Greenwich.

The fall autumnal equinox in the Northern Hemisphere is only 11 days away. This signals generally improved HF propagation, even with no solar activity. As mentioned in past bulletins, even with the quiet Sun, worldwide propagation is still possible, but at lower frequencies. Fifteen and 10 meter openings are rare, but 40, 30, 20 and even 17 meters have the better prospects.

John Parnell, K7HV, of Seattle, Washington, sent a link to a video he made while operating with just four W on a Pacific Coast backpacking trip last week on Washington State's Olympic Peninsula. He used a simple radio he built from a kit and a very basic wire antenna. John noted that HF conditions on a trip to the same place in 2007 were better. Checking the data in this bulletin from 2007, August 23-29 had an average daily sunspot number of 12.9, August 30 through September 5 was 16.1, and then for several weeks there were no sunspots.

Watch the video and see photos. Note that in the video, you can hear a snippet of last week's ARRL DX Bulletin transmitted in CW from W1AW. How do we know this, with just a few seconds of copy? By comparing the few received characters to last week's bulletins on the ARRL Web site!

Ronnie Borkgren, NN0L, of Anamosa, Iowa, writes to say he would like to see more detail in some of the reports of DX worked. He wants to know what power and antennas were used. We don't mention brand names very often, but will give details such as "3-element quad," or "popular 4 element tri-band beam," and whether the antenna is homemade or commercially produced.

Mark Lunday, WD4ELG, of Hillsborough, North Carolina, gave us enough detail: He reported working VK4DHF long path on 20 meter CW on September 8 at 2130 UTC. Mark was running just 5 W and using a low-slung dipole.

Mark Bell, K3MSB, of Airville, Pennsylvania, reports he is seeing better propagation to Southeast Asia in the past week. He didn't give his power, antenna or mode, but says that "after months upon months of really awful propagation on 20 meters into the Southeast Asia region, things looked up during the past week. I worked 9V1YC (Singapore) on September 3 at 0012 UTC, and heard stations from BY (China) and JT (Mongolia) on at the same time. Last night, September 9, I again heard 9V1YC on around the same time, and also worked 9M2MRS (Malaysia) at 0023 UTC. JT stations were also heard on the same day. I heard Richard, 9M2MRS, another night around 0030 UTC, but he was too weak to work. Looking back, there seems to (finally) be some nice openings from the East Coast into the Southeast Asia region around 0030 UTC the past few days. Most of the time the signals were not strong, but the QRN was almost non-existent and they were 'weak but workable' as the saying goes."

Frank Hertel, a consulting broadcast engineer, sent an e-mail with his observations of sporadic-e skip in the summer. For some reason, he hasn't observed any this year, but of course he isn't trying to receive weak signals on VHF. His clients become concerned when a distant signal interferes with their local broadcast: "Since part of what I do is to operate a Frequency Measuring Service for broadcasters, I have a 100 foot tower with some pretty fair antennas. I also have antennas at about 20 feet which I use for phase canceling of unwanted signals when required. I have the assortment of horizontal, vertical and H+V when combined and phased and level balanced.

"When the interference does happen, the horizontal antennas are most affected. Often the 100 foot FM band antenna doesn't experience as much interference reception as my 20 foot high FM band antenna. The 100 foot antenna never delivers as much signal strength (being commercial broadband VHF, 40-300 MHz), as does my 20 foot 12 element FM band antenna, but when the interference does hit, the 100 foot antenna does a better job (receiving more of a direct signal path from local signals vs the interfering signal from above). On non-interfering days, the 20 foot antenna actually out-performs the 100 foot FM antenna, since the 100 foot FM antenna, on a normal day, gets many unwanted signals (150 miles and beyond) that interfere with the signals I want to measure (100+ miles, and locals).

"Once in the UHF TV band range, the problem doesn't often happen, but when it has happened it always seemed to be on very cold and dry winter nights, when the weather conditions are over a very wide spread area. As I can best recall, many years ago my home UHF TV antenna (15 feet) received Denver Colorado. I live in Evansville Indiana, about 1000 miles from Denver. I remember in the 1970s that Havana, Cuba had a TV Channel 2. Every August and September, I would disconnect my outside VHF antenna (to keep from receiving Terre Haute, Indiana's channel 2) and hook up a pair of rabbit ears. Havana, Cuba was quite watchable. I always knew when Havana was watchable because the reception of channel 2, in Terre Haute would become quite scrambled. I would see 10 kHz visual beat, due to the frequency offset of the two carriers."

Very interesting info from a non-ham. We sent him a link to an APRS network that automatically reports VHF propagation, and another that predicts propagation via the troposphere.

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 in The ARRL Letter. 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.




Instragram     Facebook     Twitter     YouTube     LinkedIn