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Re: Fwd: ARLP012

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  • sdrcrazed
    Thanks Bruce. Posted at the SDRbuzz.com forum... Ed KT6F
    Message 1 of 2 , Mar 28, 2010
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      Thanks Bruce. Posted at the SDRbuzz.com forum...

      Ed KT6F

      --- In softrock40@yahoogroups.com, Bruce Tanner <bet110@...> wrote:
      >
      >
      >
      > -------- Original Message --------
      > Subject: ARLP012
      > Date: Sat, 27 Mar 2010 15:42:34 -0700
      > From: Tad Cook <k7ra@...>
      > Reply-To: k7ra@...
      > To: k7ra@...
      >
      >
      >
      >
      > Probably due to the troubled ARRL website upgrade, the propagation
      > bulletin I sent to HQ 36 hours ago was never posted or forwarded.
      >
      > So I am sending this out to contacts, and please send it on to your ham
      > contacts. Let's make this viral, at least until Monday, March 29, 2010!
      >
      > If you are not an amateur radio operator, sorry to bother you.
      >
      >
      >
      > SB PROP @ ARL $ARLP012
      > ARLP012 Propagation DE K7RA
      > QST de W1AW
      > Propagation Bulletin 12 ARLP012
      > From Tad Cook, K7RA
      > Seattle, WA March 26, 2010
      > To all radio amateurs
      >
      > Average daily sunspot numbers were down nearly five points this week to
      > 24.6.
      >
      > New sunspot group 1057 appeared on March 23, and by March 24 was
      > thirty-eight times its original size. It covered ten one-millionths of
      > the solar hemisphere on Tuesday, and on Wednesday it grew to 380 one
      > millionths. On Thursday new sunspot group 1058 appeared, and the total
      > area for both groups expanded to 401 millionths of the solar hemisphere.
      > Total sunspot area has not been this large since February 8, when the
      > total was 460 one-millionths. (The numbers given for Wednesday are a
      > revision of the numbers for the same day given in yesterday's ARRL Letter).
      >
      > The largest area covered during all of 2009 was 380 on October 29,
      > followed by 310 on December 18. March 23 through April 3 2008 was a
      > period of very strong sunspot activity, and on March 26-28 the area
      > covered by three sunspots was 520, 510 and 410 one-millionths of the
      > solar surface.
      >
      > The spring equinox was last Saturday, March 20, and HF radio conditions
      > are good, with quiet geomagnetic conditions. NOAA and the U.S. Air Force
      > predict solar flux of 88 for today, March 26, and 89 for March 27-31.
      > This is higher than the average solar flux for this week, 84.2, and last
      > week, 87.6, and the week before, 78.6. Our reporting week for data at
      > the end of this bulletin is always Thursday through Wednesday, and we
      > haven't reported a weekly average solar flux above 89 since ARLP007,
      > which had 90.6 on February 11-17.
      >
      > NOAA predicts a bit more geomagnetic activity (but not much!), rising
      > from a planetary A index of 5 on March 26 to 7 on March 27 and 8 for
      > March 28-31. Geophysical Institute Prague expects quiet to unsettled
      > conditions March 26, quiet March 27-29, quiet to unsettled March 30-31,
      > and a return to quiet for April 1, the day that NOAA predicts a
      > planetary A index of five.
      >
      > Last week for the first time we presented the trailing 50-day average of
      > daily sunspot numbers, 27.34. This week it is 28.18.
      >
      > This weekend is the CQ World Wide WPX SSB Contest. HF conditions should
      > be good.
      >
      > Harry Gross, KC2FYJ of Mineola, New York wrote in with questions about
      > the numbering of sunspot groups, which is different than the sunspot number.
      >
      > Harry asked, "First, what's the scheme (e.g. why is a particular group
      > referred to as 1055, for example)? Is it the 55th group seen in 2010
      > perhaps? Or is it something more esoteric?"
      >
      > "Second, how do you decide that a particular group is `returning'? I
      > presume it's because it's circled the Sun and is returning on the other
      > side again. However, how can you be certain it's the same group, since
      > there is a wide (but now narrowing, thanks to STEREO) area were we can't
      > observe on the far side of the SUN? Couldn't the group have disappeared,
      > and a new one formed in its place?"
      >
      > The sunspot groups are numbered consecutively, starting with 0, and when
      > group 9999 emerges, the next new group will be 0 again. I have also seen
      > them expressed as five digits, so the current sunspot 1057 this week
      > would be 11057.
      >
      > If you go to http://spaceweather.com/ and look at the Archives section
      > in the upper right, change the date to June 15, 2002 and click View.
      >
      > Note the numbers on the solar image on the left side are up in the 9990+
      > range. Now click Forward on the upper right to advance the date to June
      > 16. Note the piece about Sunspot Zero. I don't know why the image
      > doesn't show sunspot 2. Perhaps it emerged, was numbered, then faded in
      > less than a day. Perhaps that is also why paging backward does not
      > produce sunspot 9999.
      >
      > It looks like we went from group 321 to 1057 over the past seven years.
      > If sunspot groups were to continue emerging at the same rate, which has
      > been slow recently, it could take us until April 14, 2095 to reach group
      > 0 again, a pretty rough guess. That will be less than a month and a half
      > short of my birthday at age 143, perhaps around solar cycle 32.
      >
      > I get my information second hand regarding which groups are returning,
      > and do no direct observation myself. I think they can be recognized
      > possibly from magnetic signatures, and also the timing. It takes about
      > 27.5 days for a complete solar rotation, but it varies with latitude,
      > because the sun is a big ball of (very hot) gas. At the equator the
      > period is less than 26 days, and toward the poles it is about 36 days. A
      > few references on this are http://tinyurl.com/yhxjr5g,
      > http://tinyurl.com/yktkwrq and http://tinyurl.com/ykguzeo.
      >
      > John Buttolph, N1JB of Lake Elmore, Vermont wrote in with information on
      > a Navy map (see http://tinyurl.com/yhpfcwd) showing letter designations
      > for each time zone. Z or Zulu time as we all know is for the prime
      > meridian, or Greenwich Mean Time. But when it is 1200Z, it is 0400U on
      > the West Coast, and 0700R in Newington, Connecticut. Click on the map
      > for greater detail.
      >
      > John wrote, "The world is divided into 24 time zones, and each is
      > assigned a letter. The U.S. Navy, as well as civil aviation, uses the
      > letter "Z" (phonetically "Zulu") to refer to the time at the prime
      > meridian. Proceeding eastward from Greenwich, the zones are designated
      > with the Latin alphabet letters beginning with "A" or "Alpha" time. [I
      > do not know why the prime meridian time zone was given the last letter
      > of the alphabet rather than the first!] Not all letters of the alphabet
      > are used. For various reasons having to do with population centers and
      > other cultural reasons, the time zones do not strictly follow the
      > meridian lines, and some time zones vary by the half-hour".
      >
      > Matt Pastorcich, KJ4NBM of Mobile, Alabama was surprised to work VK2JB,
      > John Baylis in Hobart, Tasmania last Saturday, March 20 at 1246z using
      > PSK31 on 20 meters. That isn't a promising time for that 9,300 mile
      > short path route, and Matt was even more surprised to learn that John
      > was running 2 watts into a loop antenna made for 80 meters. Matt uses a
      > vertical. A better time would be 0500z-1000z, or even better would be 30
      > meters around 0730z-1300z or 40 meters 0800-1200z.
      >
      > Wolf Urban, DK8MZ in Fuerstenfeldbruck Germany wrote to comment on 15
      > meters. Nearly two weeks ago, on Saturday, March 13 he worked Rob
      > Struppeck, V73RS on the southernmost island of Kwajalein Atoll. Wolf
      > uses a TH3 Yagi at 12 meters high, and said that Rod had a very robust
      > S9 signal on 15 meter SSB. Wolf thinks this is a hopeful sign, and said,
      > "I can't remember when I last heard such a strong signal from that part
      > of the world, (the most difficult one for the Europeans on the high
      > bands) even during periods of much higher solar activity!"
      >
      > Don't miss K9LA, Carl Luetzelschwab's excellent monthly propagation
      > column in WorldRadio, available free, online at
      > http://www.worldradiomagazine.com/. Just right-click on the image of the
      > front cover to download the PDF, and find Carl's column on ionosphere
      > modeling on page 36.
      >
      >
      > If you would like to make a comment or have a tip for our readers, email
      > the author at, k7ra@... <mailto:k7ra@...>.
      >
      > 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/.
      >
      > Instructions for starting or ending email distribution of this bulletin
      > are at http://www.arrl.org/w1aw.html#email.
      >
      > Sunspot numbers for March 18 through 24 were 28, 24, 25, 25, 17, 26, and
      > 27 with a mean of 24.6. 10.7 cm flux was 85.8, 84.4, 83.5, 84.8, 82.5,
      > 83.9, and 84.4 with a mean of 84.2. Estimated planetary A indices were
      > 5, 4, 7, 2, 2, 2 and 3 with a mean of 3.6. Estimated mid-latitude A
      > indices were 4, 2, 5, 0, 0, 0 and 2 with a mean of 1.9.
      > NNNN
      > /EX
      >
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