Re: Fwd: ARLP012
- Thanks Bruce. Posted at the SDRbuzz.com forum...
--- In firstname.lastname@example.org, 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
> 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.