[IRCA] Fw: ARLP006 Propagation de K7RA

["Art Blair" <artngwen@xxxxxxxxxx>]

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From: "W1AW Mailing List" <w1aw-list-request@xxxxxxxxxxxxxxxxx>
To: <artngwen@xxxxxxxxxx>
Cc: <W1AW List:>
Sent: Friday, February 09, 2007 12:12 PM
Subject: ARLP006 Propagation de K7RA


> SB PROP @ ARL $ARLP006
> ARLP006 Propagation de K7RA
> 
> ZCZC AP06
> QST de W1AW  
> Propagation Forecast Bulletin 6  ARLP006
>>From Tad Cook, K7RA
> Seattle, WA  February 9, 2007
> To all radio amateurs 
> 
> SB PROP ARL ARLP006
> ARLP006 Propagation de K7RA
> 
> Average daily sunspot numbers and solar flux were up this week,
> while average daily geomagnetic indices were down, which is a nice
> combination. Our reporting week hasn't had better geomagnetic
> stability (lower average A index) since November 16-22, 2006,
> reported in last year's Propagation Forecast Bulletin ARLP049. That
> week the planetary and mid-latitude A indices were 3.6 and 2.1,
> while this week's numbers are 5.6 and 4.3.
> 
> Conditions won't remain quiet, and geomagnetic activity should
> increase until next Tuesday, February 13. Geophysical Institute
> Prague predicts quiet to unsettled conditions for today, February 9,
> quiet conditions on February 10, unsettled to active February 11,
> unsettled February 12, active geomagnetic conditions on February 13,
> unsettled to active on February 14, and February 15 unsettled.
> 
> The US Air Force predicts a planetary A index for February 9-15 at
> 5, 5, 20, 20, 20, 15 and 5. For those same days they predict solar
> flux values of 80, 83, 83, 81, 80 and 80.
> 
> We keep mentioning the bottom of the sunspot cycle, and by some
> accounts, we are probably there, or very close. NOAA Space
> Environment Center has a new prediction in this week's Preliminary
> Report and Forecast of Solar Geophysical Data at,
> http://www.sec.noaa.gov/weekly/pdf/prf1640.pdf. Look at the table on
> page 10, and compare it with the table on page 9 in the report from
> five weeks earlier, http://www.sec.noaa.gov/weekly/pdf/prf1635.pdf.
> These are predicted smoothed sunspot numbers, averaged over a year,
> going six months prior and six months into the future for each
> month.
> 
> Notice in the most recent report that the latest smoothed sunspot
> number not in bold lettering is July 2006. That is because the real
> sunspot data actually exists for six months after that month, and
> this is the actual smoothed sunspot number, an average of averages,
> made up from the monthly averages for January 2006 through January
> 2007. If you check the report from five weeks ago, July 2006 is
> bold, because there was one month for which actual sunspot numbers
> weren't actually yet known, January 2007. So in the latest report,
> the number for October 2006 factors in three predicted but as yet
> unconfirmed monthly averages, February through April 2007, and
> December includes predicted numbers for five months, February
> through June 2007.
> 
> So in the early January report, you can see that the numbers for
> October 2006 through August 2007 were 13, 11, 10, 10, 10, 10, 10,
> 10, 10, 10 and 11. The most recent prediction for those same months
> was 14, 12, 12, 11, 11, 11, 11, 11, 11, 12 and 11. Both reports seem
> to place us at the bottom. The other clue is at,
> http://sec.noaa.gov/ftpdir/weekly/Predict.txt where the predicted
> smoothed sunspot number is 10.9 for March 2007, with 11 for both
> this month and April. March 2007 would be the lowest predicted
> smoothed sunspot number shown in this table.
> 
> Randy Crews, W7TJ of Spokane, Washington wrote to comment after last
> week's summary of monthly sunspot averages in Propagation Forecast
> Bulletin ARLP006 (see
> http://www.arrl.org/w1aw/prop/2007-arlp005.html). Randy thinks that
> the actual low for cycle 23 was last year, in February 2006, when
> the average sunspot number for the month was only 5.3. Another way
> to look at this is with a 3-month moving average based on an average
> of the daily sunspot numbers, instead of an average of averages, as
> the 13 month smoothed number is. So for December 2006 we would get
> an average of 27.2 by summing all of the sunspot numbers from
> November 1 through January 31, which yields 2507, and dividing by
> the number of days, which is 92.
> 
> Here is a table of the 3-month average of daily sunspot numbers for
> a 13-month period:
> 
> Dec 05 40.6 
> Jan 06 32.4 
> Feb 06 18.1 
> Mar 06 27.7 
> Apr 06 38.5 
> May 06 39.7 
> Jun 06 28.9 
> Jul 06 23.3 
> Aug 06 23.5 
> Sep 06 21.2 
> Oct 06 24.1 
> Nov 06 23.1 
> Dec 06 27.3
> 
> The number shown for each month is the average for the daily numbers
> for that month combined with the month preceding and the following
> month. This still shows a low minimum centered on February 2006.
> W7TJ says he likes the sunspot minimum because there are very few
> days with disturbed conditions. He says, "What I am looking forward
> to is a quiet Sun, absent of CMEs, coronal holes, X-Ray radiation
> etc, that ruin propagation." And of course, since the MUF is lower
> because of the lower solar activity, this really is the best time
> for 80 and 160-meter propagation.
> 
> Now as we move toward mid-February, we are further from the darkest
> day of the year, and half way toward the Spring equinox, which is a
> good time for HF propagation. What will HF propagation be like from
> your location today? This will vary according to which amateur band
> you use and what part of the world you are targeting.
> 
> This bulletin has mentioned W6ELprop in the past, and you can use
> this software to come up with unique propagation projections from
> your location, much better than we could do in this bulletin by
> generalizing for a region. You can get the software from,
> http://www.qsl.net/w6elprop/. A good method is to take an average of
> the three most recent sunspot numbers, and use that figure with
> W6ELprop. You can get those numbers from,
> http://www.sec.noaa.gov/ftpdir/indices/DSD.txt.
> 
> So if it is Friday morning, February 9, the average would be based
> on the sunspot numbers from February 6-8, which were 23, 23 and 22.
> That averages to about 22.7. When you enter that number into
> W6ELprop, whether you have it set to take sunspot number or solar
> flux, you can always get the right choice by preceding the sunspot
> number with the letter S. So that would be S22.7 for today.
> 
> W6ELprop will also work with the K index, and you can get the
> current mid-latitude K index from WWV. The current WWV numbers are
> always available at, http://sec.noaa.gov/ftpdir/latest/wwv.txt.
> 
> Of course, you will want to customize the program for your own
> location, based upon latitude and longitude. There are a variety of
> ways to find these coordinates, but one easy method that gets you
> close enough is to do a ZIP Code search at,
> http://www.gpsvisualizer.com/convert?form=address. Be careful when
> you enter the numbers, because W6ELprop expects west longitude as a
> positive number, and on this web site they use the common standard
> in which east longitude is positive. So for those of us west of
> Greenwich, England, the prime meridian, we would turn that negative
> longitude into positive for the W6ELprop software.
> 
> Given the average sunspot number for the previous few days, suppose
> we are in Atlanta, Georgia, and want to know what the bands will be
> like toward Brazil. If this is the first time using the program, we
> can set up our location by clicking on Options at the top.
> 
> To make a projection, bring up the program, click on Predictions at
> the top, then select On-Screen from the drop-down menu, and then use
> the tab key to navigate through the various fields, entering PY for
> Brazil in the Prefix or Locator field. When the calculation is made,
> we can see that as the MUF rises above 22 MHz, 15 meters would
> likely open around 1330z. Signals should stay strong during the day,
> and get stronger before dropping out around 2300z when the MUF drops
> below the 15-meter band.
> 
> A great propagation program is ACE HF Pro, which gives some very
> fine graphic visualizations of propagation. You can learn about it
> from, http://www.hfradio.org/ace-hf/ or from,
> http://home.att.net/~acehf/. That first link was from Tomas Hood,
> NW7US, who in addition to editing the monthly propagation column for
> CQ Magazine, has a fine web site devoted to radio propagation. It
> has been offline for several months, but is back on at,
> http://hfradio.org/backon.html.
> 
> If you would like to make a comment or have a tip for our readers,
> email the author at, k7ra@xxxxxxxxx
> 
> For more information concerning radio propagation, see the ARRL
> Technical Information Service 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/.
> 
> Sunspot numbers for February 1 through 7 were 31, 36, 35, 28, 25, 23
> and 23 with a mean of 28.7. 10.7 cm flux was 89.9, 90.3, 87.3, 83.7,
> 83, 81.9, and 82, with a mean of 85.4. Estimated planetary A indices
> were 8, 2, 3, 2, 6, 8 and 10 with a mean of 5.6. Estimated
> mid-latitude A indices were 7, 2, 1, 2, 4, 6 and 8, with a mean of
> 4.3.
> NNNN
> /EX
> 
> 
>

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