ARLP016 Propagation de K7RA

No sunspots for seven days, as of Thursday, April 10. We may see sunspots return around April 21-28. This is based on recent activity rotating out of view around the Sun and (we hope) reappearing later this month.

If you look at, http://www.swpc.noaa.gov/ftpdir/forecasts/45DF/041045DF.txt, which was Thursday's forecast, you see predicted solar flux remaining at 70 until April 20, when it reaches 75, then 80 on April 21. The predicted higher solar flux should correlate with the return of sunspots. This prediction is updated daily after 2100z. After 2100z April 11 you can see the new prediction by changing 041045DF.txt at the end of the URL to 041145DF.txt. You can also go to, http://www.swpc.noaa.gov/ftpmenu/forecasts/45DF.html to select a daily forecast from the list, but frequently there is a delay before the latest forecast is listed, and you can see it much sooner by changing the date in the URL as shown above.


From that same forecast you can see quiet geomagnetic conditions predicted until April 22-24. Geophysical Institute Prague predicts quiet to unsettled conditions April 11, quiet April 12-13, quiet to unsettled April 14, unsettled April 15, quiet to unsettled April 16, and back to quiet on April 17.

Rob Steenburgh, KA8JBY sent some links useful for detecting sunspots on the Sun's far side, using helioseismography. See, http://gong.nso.edu/data/farside/ and, http://soi.stanford.edu/data/full_farside/ for images. Note that you can also animate these to see recent activity in motion. The technique is described at, http://soi.stanford.edu/press/farside_Feb2006/web/index.html.

In Propagation Forecast Bulletin ARLP007 (see http://www.arrl.org/w1aw/prop/2008-arlp007.html) in mid-February, we mentioned an article in a daily business publication which spoke of an upcoming Maunder Minimum. In the article were fabricated quotes from Dr. Kenneth Tapping, who works at the observatory in British Columbia where we get our daily solar flux data.

I was surprised to see this same article in the monthly VHF column in CQ Magazine recently. But I saw it on March 31, and it was the April issue. I understand that this was really supposed to be some sort of April Fools' jest, but it went awry, probably due to miscommunication with the editor, who was already running a traditional whimsical April item. Once edited, it lost the April 1 flavor.

Of course there is a long tradition in amateur radio publishing regarding strange and fantastic articles in the April issue. Sometimes it is difficult to tell. For instance, as a 12-year old Novice I was unaware of this tradition, and was very interested to read in an April QST about some new paint that could be applied to towers. It was supposed to "shift" reflected light "outside the visible spectrum," and therefore render the structure invisible. Well, nearly so. It should still block light from passing through it, but the article claimed the effect was some kind of fuzzy non-image, a sort of visual void of uncertain nature.

I didn't realize that this was a joke until reading the Letters section in the May issue. Imaginative readers had a lot of fun with this, and one woman wrote that her ham husband was trying out the paint on a recent Saturday, and she hadn't seen him since.

Mike Schatzberg, W2AJI of Tryon, North Carolina wrote to report conditions during the recent period when we actually had daily sunspot activity. He was mentioned previously in this bulletin, in 2006 in Propagation Forecast Bulletin ARLP047 (see http://www.arrl.org/w1aw/prop/2006-arlp047.html). He wrote again about excellent conditions on 20 meters.

On April 4 Mike wrote, "I had to let you know about the unusual and steady strong signals I have been working on 20 meters the past 3 days. East coast propagation to the Far East and Indonesia have been extraordinary. Low power stations, less than 100 watts, and with wire antennas abound, and I am able to read them with S5 to S9 signal strengths on my Orion II transceiver."

He continues, "Two Americans, HS0ZCX, Chuck, with only 100 watts, and a wire beam antenna, and XU7ACY (NO2R), Peter, have been booming into the East Coast with S9 signals. They are heard during the morning hours at about 13:00 Zulu, along with Ralph, HS0ZSC who is also very strong. YB0BCU, Yan, is always S9 from Jakarta during the same time period."

Mike goes on to say, "The evening hours have also been a delight into the Orient. Propagation remains good into Japan for much of the night. But many lower power stations can also be worked on SSB, from both China and Taiwan. Last night, between 01:00 and 03:00 Zulu, once you steer around the many calling Asian Siberian stations, Japan, China, and Taiwan were extremely active. BD2QAF, BU2AQ, JA2AXB, all had S5 or better signals with low power."

He says, "I should add that short path is again open in the evening hours back into the South Pacific. Todd, ZL2SP, was mobile, with 100 watts and a mobile whip, and he was S5 here. VK signals were Q5 during this period also."

Mike continues, "It seems that many American stations are not aware of the late evening openings as yet, and the bands are really quiet while working the low power DX. If this is just the beginning, and we are still enjoying sunspots from Cycle 23, with little action from new Cycle 24, how much better will things get? I guess I better get my log periodic finished for the higher bands because 15 and 10 are already having their 'DX Moments!'"

He ends by saying, "I have been using my usual 20 meter monoband Yagi, with 44 foot boom, at 75 feet for DXing. It doesn't get much better than this. Strong signals and little QRM. Enjoy."

Mike sure has some nice antennas in a great location. See them at, http://home.earthlink.net/~cherokeehillfarm/id2.html and http://www.qrz.com/w2aji. Note the last link shows he has been looked up over 41,000 times on that site. That indicates a very active ham. See also on his personal web site he has photos of other stations and their antennas. Don't miss VK3MO's photos at, http://home.earthlink.net/~cherokeehillfarm/id3.html.

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For more information concerning radio propagation, see the ARRL Technical Information Service web page at, http://www.arrl.org/tis/info/propagation.html. For a detailed explanation of the numbers used in this bulletin see, http://www.arrl.org/tis/info/k9la-prop.html. An archive of past propagation bulletins is at http://www.arrl.org/w1aw/prop/. Monthly propagation charts between four USA regions and twelve overseas locations are at http://www.arrl.org/qst/propcharts/.

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Sunspot numbers for April 3 through 9 were 14, 0, 0, 0, 0, 0, and 0 with a mean of 2. 10.7 cm flux was 76.4, 73, 71, 69, 69.1, 69.8, and 68 with a mean of 70.9. Estimated planetary A indices were 2, 11, 21, 18, 12, 9 and 12 with a mean of 12.1. Estimated mid-latitude A indices were 2, 8, 9, 11, 9, 6 and 9, with a mean of 7.7.
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/EX

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