SB PROP @ ARL $ARLP019 ARLP019 Propagation de K7RA ZCZC AP19 QST de W1AW Propagation Forecast Bulletin 19 ARLP019 From Tad Cook, K7RA Seattle, WA May 13, 2011 To all radio amateurs SB PROP ARL ARLP019 ARLP019 Propagation de K7RA As reported in the ARRL Letter, on Wednesday May 11 six sunspot groups were visible, but that number shrunk to two on Thursday. Daily sunspot numbers declined from 84 to 29 over those two days as well, but the average sunspot number for the reporting week (Thursday, May 5 through Wednesday, May 11) grew by nearly 7 points from last week to 74.6. The latest forecast shows planetary A index of 10 for today, May 13, then 8 on May 14-16, 10 on May 17, 8 on May 18, and 5 on May 19-25. The next possibly big geomagnetic period is May 27, with a planetary A index of 22. The same forecast predicts solar flux of 95 on May 13-14, 90 on May 15-19, and 110 on May 20-30. Geophysical Institute Prague predicts quiet to unsettled conditions May 13, quiet May 14, quiet to unsettled May 15, unsettled May 16-18, and quiet to unsettled again on May 19. On May 9 NASA released a slightly revised prediction for the peak of Cycle 24, placing it at a smoothed sunspot number of 69 in June 2013. But a month earlier the estimate had a peak of 62 in July 2013. Last month NASA was predicting this cycle as the weakest in 200 years, but the update places it as the weakest in the last century. These are Zurich sunspot numbers, which are always quite a bit lower than the NOAA SESC numbers that we report here. The NOAA numbers show a peak at 90 around February through July 2013. On May 10, Rol Anders, K3RA of Elkridge, Maryland wrote, "After a slow week or so, propagation has rebounded with extremely strong signals from Europe and Central Asia on 20 meters for several hours after their sunrise time. Many 30 and 40 dB over signals heard in Maryland. I think there have been a lot of tardy arrivals at work in EU and Central Asia as the hams have had difficulty pulling themselves away from such great conditions in the morning! Also, 17 meters has been very good in the evening with JAs and other Asian stations coming back to CQs 3 hours after sunset on the East Coast. 15 meters has been open to the Far East after sunset as well. Most interesting was working JQ1QKK short path on 20 meter phone at 3 pm his time, 2 AM east coast time! "One 'trick' that I sometimes use to find openings is to look for 'analogous openings' at my latitude. If I can work a DX station close to my latitude at a certain time of the day, then it is likely that I'll be able to work stations at that latitude the same distance away in the other direction when my local time is the same as that first DX station's was. Perhaps this is best explained by an example: the latitudes of JA and EX/EY/EZ/YA are not too different from Maryland, and they are both roughly the same distance away from me. So, if JQ1QKK in the example above was working me at 3 pm his time (2 am my time), there should be an opening to the general EX/EY/EZ area from MD at 3 pm my time, 2 am EX/EY/EX time. This can be extended to other latitudes if you know what DX stations at your latitude are working. For instance, if I hear stations at my rough latitude (EA, I, SV, EX, JA) working a path, I should have that same path when my local time is the same as theirs was when they experienced those paths. Of course, my path will be to an entirely different part of the world." Mark Bell, K3MSB of Airville, Pennsylvania wrote, "Had some nice 6M sporadic-E action here around May 3. Worked YV4DYJ in FK50 at 2253Z. Stations from LU were coming in quite strong the next two days." N0JK reports from Kansas that on May 5 he worked LU4FW on 6 meters with a sporadic-E trans-equatorial link. It was at 2138z, and he was using an indoor dipole. Rich Molinski, WB2KWF of Smithfield, Virginia reported from FM16qw that on May 2 he worked 9Y4D and YV4DYJ on 6 meters using 80 watts and a 3 element beam at 35 feet, with 5x3 reports each way. On May 6 he reported, "I was amazed at the propagation! It's nice to see 6m open up. Each night this week, 6 has been open to some degree." Bob Elek, W3HKK in central Ohio reports an E-skip opening on May 5 on 6 meters. He reports, "A C6 was 59+20 and had half the US calling him on SSB. Then for the first time in my 55 year ham radio career: TE skip to Argentina! (Interestingly I had just finished reading the VHF column in CQ Magazine describing how May was the poorest month for TE skip and not to expect it.) Well, around dinner time in Ohio, on May 5th there it was. The 6M band literally teeming with Argentine stations, mostly on SSB, from 50.1 to 50.13 MHz. LU after LU working pile ups, calling CQ, and coming in between 5x3 to 5x9 (on my 5 el Yagi, 10 ft above my rear patio, equipped with the standard Armstrong rotator, and fed by an IC7600 100w rig). "At 2125z I worked LW3EX on 50.101 CW, then at 2133 9Y4VUX on 50.100 CW, and then at 2200z LU9EEM on 50.120 SSB, all with sigs between 57 and 59! In between I tuned around for other countries and passed up on many LUs. Another local op worked the VP8 (Falkland Islands), and a couple spots showed one station in OA and CE coming through but I didn't hear them. "So, in summary, a very telescopic opening via TE into Argentina lit up 6M, and when things quieted down at around 2230z, I left for dinner a little late but a very happy camper." Roger Gibson, K4KLK of Raleigh, North Carolina (in FM05) reports, "Six was open all day May 5 to WI area and then FL. I was surprised to hear LU4FW FF97 on halo antenna in garage. I quickly turned antenna south then connected the 4 El Quad 20 feet up and got him on first call with 100 watts. Not many takers but signal was very strong 59+ more like F2 and no fading. Contact made on 50.125 SSB at 2200Z. He was in for several minutes." Both K5LJ and N4ZQ wonder why it seems that most sunspots appear in the Sun's northern hemisphere so far in this cycle. I ran this by K9LA who says, "Hemispherical asymmetry of sunspots has been known and studied for quite a while. I don't think there's an air-tight explanation yet, but it is tied to the Sun's conveyor belt. So what's happening now is 'normal' in the sense that it's been seen before in other cycles." He noted that butterfly diagrams of Cycle 20 show this predominance toward the beginning of the cycle, around 1965. If you would like to make a comment or have a tip for our readers, email the author at, k7ra@arrl.net. For more information concerning radio propagation, see the ARRL Technical Information Service web page at http://arrl.org/propagation-of-rf-signals. For an explanation of the numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. Find more good information and tutorials on propagation at http://mysite.ncnetwork.net/k9la/index.html. Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation. Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins. Sunspot numbers for May 5 through 11 were 95, 71, 38, 61, 93, 80, and 84, with a mean of 74.6. 10.7 cm flux was 104.9, 101.9, 102.2, 102.2, 103.7, 97.5, and 94.1, with a mean of 100.9. Estimated planetary A indices were 7, 4, 4, 2, 3, 8, and 6, with a mean of 4.9. Estimated mid-latitude A indices were 5, 3, 3, 0, 2, 5, and 7, with a mean of 3.6. NNNN /EX