[DX-NEWS] ARLP018 Propagation de K7RA
SB PROP @ ARL $ARLP018 ARLP018 Propagation de K7RA ZCZC AP18 QST de W1AW Propagation Forecast Bulletin 18 ARLP018 From Tad Cook, K7RA Seattle, WA May 4, 2012 To all radio amateurs SB PROP ARL ARLP018 ARLP018 Propagation de K7RA Average daily sunspot numbers declined 38 points to 106.7 this week, and average daily solar flux declined nearly 18 points to 116.2. Predicted solar flux is 115 for May 4-6, 110 on May 7-10, 120 on May 11, 130 on May 12, 135 on May 13, 140 on May 14-17, 135 on May 18-21, and 130, 125, 120, 115, 110 on May 22-26 and 105 on May 27-31. Predicted planetary A index is 5 on May 4-8, then 10, 10 and 8 on May 9-11, 5 on May 12-13, 8 on May 14-15, then 5, 8, 5, 8, and 10 on May 16-20, 15 on May 21-23, 8 on May 24, 5 on May 25 through June 4, followed by 15 on June 5-6. The NASA solar cycle prediction from the Marshall Space Flight Center at http://solarscience.msfc.nasa.gov/predict.shtml changed over the past month. The predicted maximum smoothed international sunspot number declined slightly from 61 to 60, but still is predicted for Spring 2013. The date of the new prediction is May 1, 2012 and last month's was on April 2, 2012. International sunspot numbers have much lower values than the sunspot numbers we use in this bulletin. Sunspot numbers have generally declined from a peak during Fall 2011. We look at a 3-month moving average every month, and now that we know the numbers for all of February through April, we know the average sunspot number centered on March, which is 71.2. The 3-month moving sunspot number averages centered on January, 2011 through March 2012 are 35.3, 55.7, 72.3, 74.4, 65.9, 61.5, 63, 79.6, 98.6, 118.8, 118.6, 110, 83.3, 73.7 and 71.2. The three month moving average smooths out the numbers so we can see a steady downward trend since October and November 2011, when the numbers were 118.8 and 118.6. But looking at the monthly averages, we can see a recent uptick. The monthly average sunspot numbers for October 2011 through April 2012 are 123.6, 133.1, 106.4, 91.4, 50.1, 78 and 84.5. Note that the average sunspot number for the past week - 106.7 - is higher than any monthly average since December 2011. Interesting article out of Cornell University, The Science Behind Solar Storms. Read it at, http://www.cornellsun.com/section/science/content/2012/05/02/science-behind-solar-storms. Jim Spears, N1NK of Tiverton, Rhode Island, Roger Larson, KF6IVA of Harrison, Maine, Paul Dluehosh, N4PD of Leesburg, Virginia, Bruce Clark, K0YW of Ignacio, Colorado and Jon Jones, N0JK of Lawrence, Kansas all pointed out that the abbreviation NF that was referenced in the last bulletin, Propagation Forecast Bulletin ARLP017, refers to Noise Figure, not Noise Floor. N0JK sent this link: http://en.wikipedia.org/wiki/Noise_figure. K0YW offered the following comments about noise figure and preamplifiers: At 6 Meters and below the employment of a preamp ahead of most modern transceivers is not likely to result in any noticeable improvement, as the ambient thermal noise from the earth and sky background is high enough to readily overcome the sensitivity threshold of the existing receiver's RF stage/s, especially if the myriads of local man made noise sources are added in. It is this combination of factors that will establish the 'Noise Floor' that the radio sees. Even if the receiver's sensitivity is improved by lowering its noise figure - either at the receiver or with an external antenna mounted preamp - it will not generally improve performance vs. weak signals at or under the existing noise floor. Such preamps do a good job of making that noise louder along with the weak signal, resulting in no real S/N improvement. Depending on its gain it can also seriously degrade the receiver's dynamic range, increasing the likelihood of overload or cross modulation interference from strong, close-by stations that are off frequency. Preamps become effective if receive feedline loss is excessive, or if the receiver noise figure is poor. This condition is very rare at HF and 6 meters. It usually becomes a factor at frequencies in the UHF region and higher, especially where extreme feedline lengths or lossy coaxial feedlines are used. Every dB of feedline loss will be seen as an extra dB increase in the receiver's noise figure. While this is a serious consideration at 432, 1296 and higher, it is of little concern at HF and 6 Meters where preamplifier equipped transceivers achieve noise figures in the 4-8 dB region. At 6 meters, these noise figures are very adequate to hear the weakest signals. Good feedline, like LMR series, waterproof versions of 9913 or 1/2 inch Heliax on short runs of less than 150 ft are a lot cheaper way to optimize performance on 6M than an expensive antenna mounted preamp. Rich Zwirko, K1HTV sent in the following propagation report: The HF bands were in pretty good shape when the 7O6T DXpedition to Yemen showed up on April 30 at 2104Z with an S9+ signal on
[DX-NEWS] ARLP018 Propagation de K7RA
SB PROP @ ARL $ARLP018 ARLP018 Propagation de K7RA ZCZC AP18 QST de W1AW Propagation Forecast Bulletin 18 ARLP018 From Tad Cook, K7RA Seattle, WA May 6, 2011 To all radio amateurs SB PROP ARL ARLP018 ARLP018 Propagation de K7RA Currently seven sunspot groups are visible. The average daily sunspot number is down more than seven points over the past reporting week (April 28 to May 4) when compared to the previous seven days. Average daily solar flux was off nearly five points compared to the earlier period. Sunspot group 1201 first exhibited spots on Thursday, May 5, although it was first numbered as a plage without spots back on April 28. A plage is a bright area on the Sun where sunspots may appear. Group 1207 was also new on Thursday. You can see a daily summary of sunspot groups, including their total area, at http://www.swpc.noaa.gov/ftpmenu/forecasts/SRS.html. A solar wind stream from a coronal hole induced a high latitude geomagnetic storm at the end of April. Middle-latitude geomagnetic K indices measured at Fredericksburg, Virginia went as high as 4, and the April 30 to May 2 middle-latitude A index was 17, 13 and 14. The planetary K index hit 5 on April 30, and the planetary A index over the same 3-day period was 24, 19, and 20. High latitude areas were more sharply affected, and Alaska's college K index rose as high as 7, and the same 3-day period saw the college A index at 43, 56 and 37. A bulletin received at 5:19 PM local time on Friday, April 29 (0019 UTC April 30) from IPS Radio and Space Services in Australia told of the impending geomagnetic disturbance. It read, INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL HOLE HIGH SPEED WIND STREAM FOR 30 APRIL 2011. You can subscribe to these alerts at http://www.ips.gov.au/mailman/listinfo/ips-geo-warning. The latest prediction shows more geomagnetic activity coming May 9-10, when the predicted planetary A index is 18, then 15. The USAF/NOAA prediction shows a planetary A index of 7 on May 6-8, 18 and 15 on May 9-10, 7 on May 11-12, and 5 on May 13-16, rising again to 15 on May 17, then 5 on May 18-25, and 12, 22, 18, 18 and 15 on May 26-30. The same prediction shows solar flux at 105 on May 6-8, 100 on May 9-13, and 115 on May 14-21. Geophysical Institute Prague predicts quiet conditions on May 6-7, quiet to unsettled May 8, unsettled to active May 9, unsettled May 10 and quiet again on May 11-12. Now that we are in the first week of May, it is time to look at the 3-month moving average of sunspot numbers. The latest value is another increase, from 30.1 at the end of January to 35.3 at the end of February, 55.7 at the end of March, and 72.3 at the end of April. The monthly average of daily sunspot numbers for April was 80.8, about the same as March, which was 81.1. We calculate this average by summing all of the daily sunspot numbers for three calendar months, then dividing by the number of days. Every month we incorporate a new month of data and drop off one old month. The three-month moving averages of daily sunspot numbers ending on April 2010 through April 2011 were 22.3, 18.5, 16.4, 20.4, 23.2, 28.9, 33, 35.6, 31, 30.1, 35.3, 55.7 and 72.3. There has been very little change in the predicted smoothed sunspot numbers from NOAA/SESC in the past month. Compare page 14 on the beginning of April table at http://www.swpc.noaa.gov/weekly/pdf/prf1857.pdf with the latest table, also on page 14, at http://www.swpc.noaa.gov/weekly/pdf/prf1861.pdf and only August through October 2011 have changed, each being one point lower. Each of these smoothed values represents an average of a year's worth of data, either known numbers, or predicted. For May 2011, about half of the value is based on predicted numbers. November 2010 is probably the latest date that shows a number based on all known values, as are all previous months. Bob Scaife, G7PAF offers an interesting propagation tool, the ability to monitor 20 meter PSK activity from his station in England. Go to his web page at http://homepage.ntlworld.com/bob.g7paf and click on the live screen on the left, which takes you to http://g7paf.no-ip.org:89/main. Not sure how well this works if multiple bulletin readers try to hook up at the same time, but Bob says one possible utility is to send a PSK signal and monitor it from his QTH. During ten minutes of casual monitoring I copied SQ3LMY, UA9WRG, OH2FDO, RJ6JK, RA3WBZ, OE5KEO, EA1GCD, YU7NW, F5AXG, IZ5RFR, IZ7SIA, CT2FPY, EA3AJY, EA3AHH, YU1LC, CT4RC and I6MBK. Many of those stations have photos of their radios and antenna systems on QRZ.COM, and some even have links from their QRZ.COM page to monitor their station or view them on a web cam as they operate. Ted Turk, WB8ADA of Euclid, Ohio calls our attention to an item in the current June 2011 issue of Sky Telescope, titled Why the Sun Had No Spots. Read it at http://www.nxtbook.com/nxtbooks/newtrack/st_201106/#/16. Jon Jones, N0JK reminds us that sporadic-E season
[DX-NEWS] ARLP018 Propagation de K7RA
SB PROP @ ARL $ARLP018 ARLP018 Propagation de K7RA ZCZC AP18 QST de W1AW Propagation Forecast Bulletin 18 ARLP018 From Tad Cook, K7RA Seattle, WA May 7, 2010 To all radio amateurs SB PROP ARL ARLP018 ARLP018 Propagation de K7RA Sunspots made a strong return this week, and so did geomagnetic activity. Average daily solar flux increased 4.2 points to 79.6, and on Wednesday, May 5 the daily sunspot number reached 77, the highest in nearly four years. The sunspot number hasn't been as high since May 28, 2006, when it was 78. Last Friday, April 30, sunspot group 1064 appeared, and then faded after the third day. On Sunday groups 1065, 1066 and 1067 appeared, and the next day 1063 made a reappearance, along with new group 1068. 1069 arose on May 4 and 1065 disappeared. 1070 appeared on May 5. 1069 grew quickly, and the sunspot number rose from 61 to 70 and then 77 on Wednesday, but dropped to 45 on May 6, when 1066 and 1077 disappeared. Solar flux rose steadily from 76.2 on April 29 to 83.2 on May 5, but dropped over four points to 79.1 on May 6. NOAA and USAF predict solar flux to decline over the next few days, with the May 7-10 flux values at 78, 76, 75, and 75. This probably indicates another short quiet period with little or no sunspot appearances. A look at the STEREO mission image at http://stereo.gsfc.nasa.gov/ on Friday morning shows no bright spots (indicators of magnetic activity and sometimes sunspots) coming up. STEREO achieved 89% coverage on May 6, and is expected to reach 90% on June 18, 2010. Expect 95% coverage by October 12. Along with increased sunspots came rising geomagnetic activity. The peak days were Sunday and Monday, when the planetary A index was 39 and 27, and the K index went as high as six over several three-hour periods. NOAA and USAF predict planetary A index for May 7-13 at 9, 12, 12, 8, 8, 5 and 5. Geophysical Institute Prague predicts quiet conditions for May 7, unsettled May 8, quiet to unsettled May 9-10, unsettled May 11, and quiet May 12-13. Now that April has ended, we can look at sunspot averages for the past month and the past three month period. Average daily sunspot number for April was only 11.2, down from 21.3, 31 and 25.2 for January through March. The three-month moving average centered on March was 22.3, close to the averages of 22.4 and 25.7 centered on January and February. Look on page 10 of the NOAA Space Weather Operations Preliminary Report and Forecast for May 4 at, http://www.swpc.noaa.gov/weekly/pdf/prf1809.pdf. It shows the current sunspot cycle peaking at a smoothed value of 90 in February through July 2013. Also note how the monthly sunspot numbers this year as reflected in the graph decline from the projected values. Tomas David Hood, NW7US, who edits the Propagation column in CQ Magazine, has a propagation resource at http://prop.hfradio.org/. He also has a Facebook page that features frequent reports and comments on solar activity and propagation. On Facebook do a search for Space Weather and Radio Resources at HFRadio.org. Bob Kile, W7RH had a comment regarding this week's increasing sunspot activity. He writes, Shucks Tad, I really enjoyed the last minimum of 2007-2010. The activity level on 160m was superb and conditions were fantastic even out west! Bob has been quite happy with the low solar activity and quiet geomagnetic conditions over the past few years, as his main interest is 160 meters. He lives in Las Vegas, but operates a 160 meter HF remote base station in a remote quarter of Northern Arizona. Bob has planted acres of antennas and controls the station remotely. It sits on a 20 acre piece of land that he purchased at a popular online auction site. See http://members.cox.net/midnight18/ for pictures and info. Bill Echols, NI5F of Jackson, Mississippi had a comment on the 70 MHz propagation in Europe (where it is an amateur band) and aircraft traffic, contrails, and volcanic ash. Bill writes, It very well may be that jet contrails provide the normal mechanism for enhanced 70-MHz paths rather than the jet itself. Many years ago it was noted in England that the U.S. stealth aircraft could be detected after the fact by scanning for the moisture in jet contrails between 55-MHz and 70-MHz and comparing that 'signature' against the normal metallic returns; obviously, if there had been stealth aircraft during the observation window, the number of contrail returns would be higher than the metallic returns. The jets on our stealth aircraft were modified in classified ways to minimize, and in most cases, eliminate this method of detection. I actually remember seeing something about this in amateur literature once; if I remember correctly, it was in an RSGB periodical somewhere in the early 1990s. Robert Steenburgh, KA8JBY of Houston, Texas says that the annual Space Weather Workshop at the Space Weather Prediction Center concluded a week ago, and soon material presented there will be available on the web
[DX-NEWS] ARLP018 Propagation de K7RA
SB PROP @ ARL $ARLP018 ARLP018 Propagation de K7RA ZCZC AP18 QST de W1AW Propagation Forecast Bulletin 18 ARLP018 From Tad Cook, K7RA Seattle, WA May 1, 2009 To all radio amateurs SB PROP ARL ARLP018 ARLP018 Propagation de K7RA The data at the end of last week's Propagation Forecast Bulletin ARLP017 reported daily sunspot numbers from April 16-22 were six zeros, then 11, when in fact they were zero on every day until April 21, when it was 11, then zero again the next day, April 22. Just as many zero sunspot days -- and only one day with a sunspot -- but on Tuesday, April 21, and not April 22. We had two additional days with a sunspot this week, Wednesday and Thursday, April 29-30. The sunspot number was 15 and 12 on those days. But this was another old Cycle 23 sunspot, and it appeared near the western limb, and may have either faded away completely or rotated out of view today, May 1. The data at the bottom of our bulletin shows seven days, Thursday through Wednesday for the reporting week, so the sunspot number of 12 for Thursday will appear in next week's data. Now that we have all the data for the month of April, it is time to present our running 3-month average of daily sunspot numbers, centered on March. The last time we presented this was four weeks back, in Propagation Forecast Bulletin ARLP014 on April 3. We were hoping last Fall that the sunspot minimum was centered around August 2008, when we showed the three month average centered on that month with data from July through September at 1.1. The following two averages for September and October were 2.5 and 4.5, but then it began another decline, to 4.4, 3.7, 2.3 and 2.1 for November 2008 through February 2009. The average daily sunspot number centered on March was just 1.5, so the decline continues. Why so low? From February 1 through April 30 we had very few days with sunspots, in fact only eleven. There was never more than one sunspot visible on each of those eleven days, and the highest sunspot number (an index which does not equal the number of sunspots) was just 15, and that was this last Wednesday. That is not a high sunspot number, but we haven't had one that high since November 13, 2008 when the sunspot number was 16. The only days with visible sunspots over the past three months were February 11-14 and 24-26, March 6-7, and April 21 and 29-30. That's it. And if you add all those sunspot numbers together on those dates, you get a sum of only 133. Divide 133 by the 89 days over those three months, and you get an approximation of 1.49438, or 1.5 to round it up. Here are the latest 3-month averages of daily sunspot numbers: Jan 07 22.7 Feb 07 18.5 Mar 07 11.2 Apr 07 12.2 May 07 15.8 Jun 07 18.7 Jul 07 15.4 Aug 07 10.2 Sep 07 5.4 Oct 07 3.0 Nov 07 6.9 Dec 07 8.1 Jan 08 8.5 Feb 08 8.4 Mar 08 8.4 Apr 08 8.9 May 08 5.0 Jun 08 3.7 Jul 08 2.0 Aug 08 1.1 Sep 08 2.5 Oct 08 4.5 Nov 08 4.4 Dec 08 3.7 Jan 09 2.3 Feb 09 2.1 Mar 09 1.5 So if we examine the 3-month averages since January 2007, we see what we thought was a minimum of 3.0 centered on October 2007, then another decline to 1.1 in August 2008, and now after rising slightly it has dropped again, to 1.5. And of course we have no way of knowing if next month the number will be lower or higher. If you look at the sunspot numbers for the three days with sunspots in April -- April 21, 29 and 30 -- the numbers 11, 15 and 12 only add up to 38. Divide that by April's 30 days, and the average is about 1.267, less than the 3-month average ending yesterday. So if we saw the same activity (or lack of it, actually) for May, we could see another decline at the beginning of June when we look at the averages centered on April. If by chance we have no sunspots at all through the end of May, that average would decline from approximately 1.494 centered on March to 0.681 centered on April. Last week's bulletin mentioned the Weak Signal Propagation Reporter Network site at http://wsprnet.org/drupal/wsprnet/map. This week we heard from David Witkowski, W6DTW of San Jose, California, who said that WSPR was developed by Joe Taylor, K1JT, the 1993 Nobel Laureate in Physics who brought us WSJT and JT65. David recommends http://www.physics.princeton.edu/pulsar/K1JT/wspr.html for getting set up. Also note the link selections on the left side of that page for info on WSJT and JT65. WSJT is a mode for communicating via brief meteor scatter propagation, and JT65 is useful for moonbounce and troposcatter modes. Last week's mention of the first signs of early 2009 E-skip season brought a response from Jon Jones, N0JK, who says most of the openings have been short, and best for those in Arizona, Texas, Florida and Central America. At the start of the season, conditions are better for the southern tier, but later E-layer openings improve further north. He sent a log of 6-meter contacts on April 22, from 2158-2206z on 50.125 MHz. N0JK (EM17)
[DX-NEWS] ARLP018 Propagation de K7RA
SB PROP @ ARL $ARLP018 ARLP018 Propagation de K7RA ZCZC AP18 QST de W1AW Propagation Forecast Bulletin 18 ARLP018 From Tad Cook, K7RA Seattle, WA April 25, 2008 To all radio amateurs SB PROP ARL ARLP018 ARLP018 Propagation de K7RA This week we had a couple of brief sunspot appearances, 991 and 992, but they were both from old Cycle 23, and their emergence was fleeting. On Wednesday, April 23 the planetary A index rose to 32 due to a solar wind and south-pointing Interplanetary Magnetic Field (IMF). An explanation of IMF and the significance of it pointing south are at, http://pluto.space.swri.edu/image/glossary/IMF.html. Expect geomagnetic conditions to stabilize this weekend, but again become active on May 2. Walt Knodle, W7VS of Bend, Oregon pointed out politely that the line The only previous Cycle 24 activity was close to the solar equator from last week's Propagation Forecast Bulletin ARLP017 was incorrect. He sent a magnetogram link, http://tinyurl.com/697hho, showing that in early January spot 981 was in fact high-latitude. The Spring/Summer E-layer propagation season is beginning, and Art Jackson, KA5DWI, has an interesting analysis that looks quite useful. You can get it from, http://www.swotrc.net/ProbabilityEs.pdf. Also check out his page on last Fall's 10 meter sporadic-E season at, http://www.swotrc.net/10MeterPropNet.htm. There was a tremendous response this week from readers wanting a copy of Ken Tapping's observations on the current sunspot minimum, with over 300 requests over the weekend. You can still get one emailed to you by sending a blank email to, [EMAIL PROTECTED] Any email sent to this address will get the same document. If you would like to make a comment or have a tip for our readers, email the author at, [EMAIL PROTECTED] 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/. Instructions for starting or ending email distribution of this bulletin are at http://www.arrl.org/w1aw.html#email. Sunspot numbers for April 17 through 23 were 0, 0, 13, 12, 0, 13, and 13 with a mean of 7.3. 10.7 cm flux was 69.2, 70.2, 71, 70.8, 70.9, 71.3, and 70.7 with a mean of 70.6. Estimated planetary A indices were 8, 6, 5, 4, 4, 5 and 32 with a mean of 9.1. Estimated mid-latitude A indices were 7, 5, 6, 1, 3, 4 and 17, with a mean of 6.1. /EX -- Archives http://www.mail-archive.com/dx-news@njdxa.org THE DXR is sponsored by the North Jersey DX Association. Please visit our website: http://www.njdxa.org/index.php To subscribe/unsubscribe, please send request to [EMAIL PROTECTED] and allow a few hours for acknowledgement --
