Boletim de Propagação da ARRL.

A média diária número de manchas solares para a semana passada diminuiu para pouco mais mais da metade, cerca de 52 pontos para 35,1, quando comparado com a semana anterior. A média diária do fluxo solar caiu quase 12 pontos para 90,1. Note que a partir de quarta-feira (último dia para os dados relatados ao final deste boletim) até quinta-feira desta semana o fluxo solar foi 101,5-103,3 e o número de manchas solares aumentou de 48 para 62. NOAA e a USAF preveem aumento do fluxo solar para o curto prazo, com fluxo solar em 105 em 17-20 de junho , para 110 em 21 a 23 de junho , e 105 em 24 a 26 de junho para, em seguida, mergulhar abaixo de 100 após 28 de junho. O fluxo solar para o final de semana é de 105 (24 - 26 de junho). Os índices planetários previstos para 17 a 25 de junho são de 10, 8, 5, 8, 8, 5, 18,15 e 10, seguido por 5 a cada dia até o final de junho. e Parece que um buraco coronal recorrente pode perturbar o campo geomagnético da nossaTerra, com o efeito máximo em 23 de junho, mas as condições geomagnéticas devem continuar tranquilas até domingo, 26 de junho. O INSTITUTO GEOFISICO DE PRAGA prevê condições tranqüilas para os dias 17-18 de junho, tranquilo para médio 19 de junho, de condições ativas em 20 de junho, e condições instáveis de ​​22 a 23 junho. Por alguma razão eles não ofereceram uma previsão para o dia 21 de junho. A grande notícia desta semana foi o relatório emitido a partir de uma reunião da Divisão de Física Solar da Sociedade Astronomica Americana (American Astronomical Society), na Universidade Estadual de Novo México (Novo México State University), em Las Cruces prevendo outro Mínimo de Maunder -muitas décadas com quase nenhuma manchas solares. Parece haver uma convergência de várias linhas de pensamento para esta previsão, mas felizmente há vozes dissidentes entre os especialistas. (Original abaixo). --- Em sex, 17/6/11, jjreisert@alum.mit.edu escreveu: De: jjreisert@alum.mit.edu Assunto: [DX-NEWS] ARLP024 Propagation de K7RA Para: dx-news@njdxa.org Data: Sexta-feira, 17 de Junho de 2011, 16:32 SB PROP @ ARL $ARLP024 ARLP024 Propagation de K7RA ZCZC AP24 QST de W1AW Propagation Forecast Bulletin 24 ARLP024 >From Tad Cook, K7RA Seattle, WA June 17, 2011 To all radio amateurs SB PROP ARL ARLP024 ARLP024 Propagation de K7RA The average daily sunspot number for the past week declined by more than half, nearly 52 points to 35.1, when compared to the previous week. Average daily solar flux declined nearly 12 points to 90.1. Note that from Wednesday (the last day for the data reported at the end of this bulletin) to Thursday of this week the solar flux went from 101.5 to 103.3 and the sunspot number rose from 48 to 62. NOAA and the USAF predict rising solar flux for the near term, with solar flux at 105 on June 17-20, to 110 on June 21-23, 105 on June 24-26 then dipping below 100 after June 28. Predicted solar flux for ARRL Field Day weekend is 105 on June 24-26. Predicted planetary A index for June 17-25 is 10, 8, 5, 8, 8, 5, 18, 15 and 10, followed by 5 on each day through the end of June. It seems that a recurring coronal hole may disturb our Earth's geomagnetic field, with the maximum effect on June 23, two days before Field Day, but geomagnetic conditions should be very quiet by Sunday, June 26. Geophysical Institute Prague predicts quiet conditions for June 17-18, quiet to unsettled June 19, active conditions June 20, and unsettled conditions June 22-23. For some reason they don't offer a prediction for June 21. Big news this week was the report issued from a meeting of the Solar Physics Division of American Astronomical Society at New Mexico State University in Las Cruces predicting another Maunder Minimum - many decades with hardly any sunspots. There seems to be a convergence of several lines of thought which all predict this, but fortunately there are dissenting experts. Here is the text of the release: http://www.boulder.swri.edu/~deforest/SPD-sunspot-release/SPD_solar_cycle_release.txt This contains text and images: http://www.boulder.swri.edu/~deforest/SPD-sunspot-release/ The web site for the conference: http://astronomy.nmsu.edu/SPD2011/ Douglas Biesecker of NOAA's Space Weather Prediction Center questions this hypothesis of disappearing sunspots. You can read his notes here: https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B88iFXWgVKt-NzU0Y2I3M2QtNGNkNS00ZTcyLWIxN2UtOWEwMzNmOTMzOTAx&hl=en_US&pli=1 Or if that doesn't work for you, try this: http://snurl.com/5qzxf A slideshow accompanies the notes: http://www.slideshare.net/Revkin/why-there-is-no-evidence-for-a-new-maunder-minimum-8318340 Here are several articles on related subjects, the first two contributed by Scott Bidstrup, TI3/W7RI: http://esciencenews.com/articles/2011/06/14/new.insights.how.solar.minimums.affect.earth http://www.physorg.com/news/2011-06-scientists-magnetic-ropes-solar-storms.html http://www.wired.com/wiredscience/2011/06/solar-minimum-climate/ Peter Laws, N5UWY of Norman, Oklahoma wrote: "On the morning of Memorial Day, May 30, I was alerted to a potential opening on the 2 meter band. I went to the radio room and tuned around. Sure enough - a W8! I worked W8BYA in EN70 about 1230 km from me in EM15. My question is this: Was that a Tropospheric Ducting event or was it sporadic-E? It seems to me to be long for Tropo but I don't really know the upper end for Tropo over land. Is there some rule of thumb that operators can use to try to determine which mode made the contact possible? "As exciting to me as 2 meter DX contacts are, W8BYA was the only station I heard on the band!!" My suspicion is that the mode was sporadic-E, but I don't know. Maybe some experienced VHF ops can lend an opinion on this. The July 2011 issue of QST has an informative article by Joel Hallas, W1ZR on pages 37-38 titled, "Solar Indices - What do they Mean?" In the article Joel explains solar flux, sunspot numbers, A index and K index, and what they mean for the radio amateur. The article also gives a nice plug for this bulletin. Lawrence, GJ3RAX from the Isle of Jersey writes: "Last Friday I had a phone call from GJ3YHU. That is not unusual as he lives about a mile from me. This time he was down in Meze in the south of France where he spends time regularly. He said that he had been hearing signals on 10 meters and wanted to see if there was a path between us. I was doubtful that it would be possible as my typical sporadic-E QSOs are usually to the south of Spain, Gibraltar and North Africa. The south of France would probably be too close. We chose a frequency and tried, resulting in a QSO at 5/9 each way. That lasted for nearly 5 minutes before fading out. "His equipment was an IC-7000 to a mobile whip. I was using an IC-756-Pro2 to a Cushcraft R5 which is mounted 10 feet above the ground here. Using Google Earth I estimated the distance as 485 miles. "By the time I get to replace my broken beam for 6 m the sporadic-E season will be over but I should be back on that band and the higher VHF bands later in the year." Thanks, Lawrence! 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 June 9 through 15 were 46, 35, 37, 16, 16, 48, and 48, with a mean of 35.1. 10.7 cm flux was 87.5, 86.7, 84.5, 84.6, 86.6, 99.3, and 101.5, with a mean of 90.1. Estimated planetary A indices were 11, 8, 11, 9, 8, 7, and 7, with a mean of 8.7. Estimated mid-latitude A indices were 7, 7, 10, 5, 6, 7, and 9, with a mean of 7.3. NNNN /EX

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