SB PROP @ ARL $ARLP041   
   ARLP041 Propagation de K7RA   
      
   ZCZC AP41   
   QST de W1AW     
   Propagation Forecast Bulletin 41  ARLP041   
   From Tad Cook, K7RA   
   Seattle, WA  October 14, 2011   
   To all radio amateurs    
      
   SB PROP ARL ARLP041   
   ARLP041 Propagation de K7RA   
      
   Robust solar activity continues.  Check http://www.spaceweather.com   
   for daily images of the Sun, and you'll see it is full of spots. You   
   can also use the archive feature to view the position of sunspots   
   for previous days.   
      
   The average daily sunspot number for the week (95.4) was about the   
   same as last week (96.7) and the week before (96.1). The number   
   hasn't stayed steady though, with daily variation as low as 82 and   
   as high as 126 over the past two weeks.  You can check   
   http://www.swpc.noaa.gov/ftpmenu/forecasts/SRS.html for daily   
   updates showing which numbered groups appeared and faded away, along   
   with the relative area covered by each one.   
      
   The latest forecast from USAF/NOAA has solar flux at 135 on October   
   14-15, 130 on October 16-20, 125 on October 21 through November 2,   
   120 on November 3-5, and 125 on November 6-8.  The predicted   
   planetary A index is 5 on October 14, 8 on October 15-17, 5 on   
   October 18-27, 8 on October 28-30 and 5 on October 31 through   
   November 2.   
      
   Geophysical Institute Prague predicts quiet conditions on October   
   14, quiet to unsettled October 15, unsettled October 16, quiet to   
   unsettled October 17, and quiet October 18-20.   
      
   Lots of 10 meter activity lately, and Jeff Hartley, N8II of   
   Shepherdstown West Virginia sent this last week:   
      
   "Today, Oct 7th, the SFI was only 125 and 10M was wide open to EU at   
   1220Z (65 minutes after sunrise) with a very large amount of   
   activity. As we move into October, a bit lower SFI will produce   
   openings equivalent to those around the equinox 2 weeks ago with   
   higher MUFs. I started off the day breaking a EU pile up calling   
   7Z1TT in Saudi Arabia who was S9. I called one G running a vertical   
   and 100W who was S9 and two stations called me when signing. Then I   
   QSY'd up to 28530 kHz where there was still plenty of activity and   
   ran off about 10 QSOs before having to QRT. 10 was wide open to the   
   Moscow area and Great Britain which has been left out of many recent   
   openings; M0RAD was S9+25 dB. XU7SSB (Cambodia) was worked on 15 CW   
   S7 around 1300Z.   
      
   "T32C has been good strength to loud on all bands in the past week   
   and I've logged them on every HF band except 40M including both   
   modes on 15, 12, and 10M. 10M is routinely open to the Rockies and   
   west coast an hour or more after sunset and I was lucky enough to   
   have VK4FAXA running 10W call in from McClay Island, IOTA OC-137, on   
   10M last night. 10M conditions have been great except over the pole   
   from here, not that many JA/Asia openings."   
      
   Michael Gutman, K2CHM of Mashpee, Massachusetts writes, "10 meter   
   propagation is certainly feeling a lot like 1958.  I worked T32C on   
   10/9 at 7:25 PM on 28.485 MHz and he was 59.  It is impressive to me   
   as I run only 100 watts to a dipole in the attic here at sea level   
   on Cape Cod."   
      
   Mark Lunday, WD4ELG of Greensboro, North Carolina wrote on October   
   11, "Nothing gets the blood moving like a 10 meter opening at   
   sunrise! BY, 4K, ZD7, VU, 4S, and of course tons of EU stations, all   
   at 0800 local, and all audible on wire antennas.  Feels almost like   
   2001 all over again!   
      
   "In fact, 10 and 12 have been spectacular this week. I am rapidly   
   closing in on 9BDXCC using only LoTW...only 25 more to go on 12 and   
   10, then that leaves just 160 for the final jewel in the crown."   
      
   You can feel Mark's excitement! Check his blog at   
   http://wd4elg.blogspot.com/.   
      
   We also receive 6 meter reports. Anibal Dos Ramos, HK3R of Bogota,   
   Colombia says that on Sunday, October 9 he made his longest distance   
   6 meter contact yet. It was 2318 UTC when he contacted KH7Y on both   
   SSB and CW, and he heard KH7Y for about 30 minutes with S9 signals.   
   He estimates the distance was 8,897 km (5,528 miles) and he heard no   
   other Pacific stations.   
      
   There is much more on 6 meters and the recent meteor showers.   
   Perhaps we can report on that next week.   
      
   Roger Harrison, VK2ZRH sent an interesting email about propagation   
   of VHF signals from Dubai in the Middle East to the Far East. He   
   wrote:   
      
   "Over September 12-16, United Arab Emirates TV signals from Dubai on   
   48.25 - 53.75 MHz, were being copied in Shenzhen in south-east   
   China, Hong Kong and the Philippines, which are all in the UTC+8   
   time zone; Dubai is UTC+4. Dan VR2HF is the HK contact, while George   
   DU1GM is located 80 km south of Manila.   
      
   "The 48.25 MHz video signal typically reached S9+20 dB on peaks.   
   The 53.75 MHz sound channel was received for short periods when the   
   MUF peaked.   
      
   "Optimum reception time was around 1200-1300 UTC, although sometimes   
   signals were received in Hong Kong as early as 1130 UTC (1930 HK   
   local time).   
      
   "The propagation path ranges from about 5900 km to 7200 km and is   
   generally in daylight in mid-September. As this is the equinoctial   
   season, when the occurrence of sporadic E is a minimum, I thought   
   the propagation was most likely to be F2, requiring two hops of   
   about 3000 km each to Shenzhen/Hong Kong, and about 3600 km to DU1   
      
   "Dubai is located about 18 degrees N geomagnetic latitude, while   
   Shenzhen and Hong Kong are at about 11-12 degrees N geomagnetic   
   latitude. Manila is directly beneath the geomagnetic equator.   
      
   "The propagation path is largely beneath the northern Equatorial   
   Ionospheric Anomaly (also known as the Appleton anomaly) in the F2   
   region, which lies generally between 10 and 20 degrees geomagnetic   
   latitude north (another forms south of the geomagnetic equator). It   
   is the region of high electron density that forms late morning local   
   time, builds during the day and can last 6-7 hours into early   
   evening.   
      
   "For the Dubai to Shenzhen/Hong Kong path, the first F2 reflection   
   point would be 1500 km east of Dubai, near the northern extent of   
   the EIA, and in the UTC+5 time zone. The second F2 reflection point   
   would be about 4500 km east of Dubai, in the UTC+7 time zone and   
   near the middle of the EIA. To support 48 MHz propagation, foF2 at   
   each F2 reflection would need to be above 14.5 MHz as a 3000 km F2   
   skip has an M-factor of about 3.3.   
      
   "The only vertical incidence ionosonde with available online data   
   that I could locate in the EIA zone is at Guangzhou, about 100 km   
   northwest of Shenzhen, and 140 km northwest of Hong Kong. Although   
   at the propagation path's eastern end, the growth of the EIA   
   "follows the Sun" westward and the Guangzhou foF2 values provide a   
   good guide as to how the EIA develops during the day, from which we   
   can infer likely foF2 values west along the propagation path. NOAA's   
   Space Weather Prediction Center lists the Guangzhou ionosonde's   
   parameters here:   
   http://www.swpc.noaa.gov/ftpdir/lists/iono_month/201109_Guangzhou_iono.txt.   
      
   "For September 13, foF2 was above 16 MHz from 0500 to 1100 UTC,   
   which implies that the highest electron density of the EIA covered a   
   longitudinal extent of 6 hours. The 1st F2 reflection point will   
   determine when the path opens as the 2nd reflection point will be   
   well covered by the EIA. As the openings commenced around 1130-1200   
   UTC, the foF2 at the 1st reflection point must have reached 14.5 MHz   
   at 0830-0900 UTC, which is 3.5 hrs after foF2 hit 16 MHz at   
   Guangzhou. The discrepancy can be put down to the fact the 1st   
   reflection point is closer to the northern edge of the EIA, where   
   the electron density would take more time to accumulate to the high   
   values found near the middle of the EIA.   
      
   "Undoubtedly, the propagation experienced was supported by 2-hop F2   
   skip east-west along the EIA.   
      
   "The Dubai-DU1GM path is reported to experience longer durations and   
   higher signal strengths than the Dubai-Shenzhen/HK path. Each skip   
   is about 3600 km, just shorter than the maximum F2 skip of about   
   4000 km. For F2 skips of this length, the M-factor is about 4, so   
   foF2 only needs to reach 12 MHz to support 48 MHz propagation, and   
   the EIA achieves this earlier and sustains it longer.   
      
   "For the record, the 10.7 cm flux over September 12-16 was 124, 129,   
   143, 141, 143, and the A index was 17, 11, 5, 4, 2 (NOAA weekly   
   figures)."   
      
   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://myplace.frontier.com/~k9la/.   
      
   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 October 6 through 12 were 99, 88, 61, 71, 87,   
   113, and 149, with a mean of 95.4. 10.7 cm flux was 123.9, 122,   
   118.4, 121, 126.4, 130.1, and 134.1, with a mean of 125.1. Estimated   
   planetary A indices were 7, 7, 7, 13, 3, 4, and 6, with a mean of   
   6.7. Estimated mid-latitude A indices were 6, 4, 5, 8, 2, 3, and 4   
   with a mean of 4.6.   
   NNNN   
   /EX   
      
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   IF you have questions or concerns regarding the accuracy   
   of information posted, or the opinions expressed, contact the content   
   originators directly.   All publications retransmitted as   
   fidonet echomail without alteration other than the removal of   
   email header and other control information which   
   is not part of the actual publication.   
      
   Gentlemens' agreements ratified by IARU regions 1 and 2 have   
   designated a global "center of activity" frequency  in  each   
   of  the  international  hf  bands.  THese are similar to the   
   concept for weak signal calling and other center of activity   
   frequencies.  Three of these have been ratified worldwide.   
      
   THese  center of activity frequencies are where stations can   
   go to render or obtain emergency assistance.   
      
   WHen casually operating or  contesting  on  hf  please  make   
   yourself  aware  of  these  frequencies,  and give them some   
   space. Remember that often stations with emergency needs are   
   not  those  utilizing  high  gain antennas and maximum legal   
   power.   
      
   TO find out more, visit 14300.net or IARU web resources.   
      
      
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