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  • ARLP037 Propagation de K7RA

    From ARRL Web site@3:633/280.2 to All on Sat Sep 16 00:08:15 2023
    SB PROP @ ARL $ARLP037
    ARLP037 Propagation de K7RA

    ZCZC AP37
    QST de W1AW
    Propagation Forecast Bulletin 37 ARLP037
    From Tad Cook, K7RA
    Seattle, WA September 15, 2023
    To all radio amateurs

    SB PROP ARL ARLP037
    ARLP037 Propagation de K7RA

    Like last week, eight new sunspot groups emerged this reporting
    week, September 7-13.

    One appeared on September 7, another September 9, four more on
    September 10, another on September 11 and one more on September 12.

    Solar activity made a nice comeback, with average daily sunspot
    numbers rising from 95.4 to 138.1, and solar flux from 137.6 to
    159.9.

    The most active geomagnetic day was September 12, when the planetary
    A index was 25. Spaceweather.com reported a "stealth CME"
    (unexpected) that had aurora visible down as far as Missouri.

    Average daily planetary A index decreased from 15.4 to 10.4, and
    middle latitude numbers from 16.3 to 11.3.

    The Autumnal Equinox in the Northern Hemisphere is just a week away,
    on September 22.

    It seems that the next sustained short term peak in solar flux is a
    few weeks off, with values between 150 and 155 over October 12-17,
    although it is expected to reach 150 on September 23-24.

    The forecast shows solar flux at 145, 148, 145 and 145 on September
    15-18, 140 on September 19-21, 145 on September 22, 150 on September
    23-24, 145 on September 25, 140 on September 26-27, 135 on September
    28-30, then 130, 135, 130 and 135 on October 1-4, 140 on October
    5-6, 135 on October 7-8, 140 on October 9, 145 on October 10-11, 150
    om October 12-13, then 155, 150, 155 and 150 on October 14-17, 145
    on October 18-19, and 150 on October 20-21.

    Predicted planetary A index is 15 on September 15, 8 on September
    16-17, then 5, 5, and 10 on September 18-20, 5, 8 and 12 on
    September 21-23, 5 on September 24-27, then 8, 12 and 8 on September
    28-30, and 5 on October 1-8, then 15, 12, 10 and 8 on October 9-12,
    5 on October 13-19, 12 on October 20, and 5 on October 21-24.

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere - September 15-22, 2023 from OK1HH.

    "A week ago, the active sunspot group AR3414 dominated the solar
    disk. It is now on the far side of the Sun. This role has been taken
    over by AR3423, now approaching the western limb of the solar disk.
    It will be followed the next day by the slightly smaller AR3425. The
    important information is that we observe a coronal hole near both of
    them (closer to AR3425). This configuration was the likely cause of
    the surprise: Few people expected the Earth to be hit by a CME on
    September 12 at 1237 UT.

    "Then a massive disturbance of the Earth's magnetic field developed.
    Its initial positive phase increased the MUF values on September 12.
    This was followed by a negative phase, which in turn caused a
    significant decrease in MUF, with worsened shortwave propagation
    conditions on 13 September. This was followed by a gradual
    improvement on 14 September, when the magnetic filament connecting
    sunspots AR3423 and AR3425 erupted. The consequence could be a G1 to
    G2 class geomagnetic storm in the Earth's vicinity on 17 September."

    Jon Jones, N0JK wrote from Kansas:

    "Sunday afternoon and evening (September 10-11) strong sporadic-E on
    6 meters took place.

    "This set up links to TEP on to South America.

    "The hot spot seemed to be south Central Kansas and northeast
    Oklahoma. KF0M in EM17 worked many South American stations. From
    EM28, the Es was not lined up that well.

    "Had many strong stations in south Texas and northern Mexico.
    Around 2250 UTC LU1MQF (FF55) and CE4MBH (FF44) appeared for a few
    minutes on 50.313 MHz FT8.

    "Any sporadic-E is a treat in the September ARRL VHF contest (which
    was last weekend). With Solar Cycle 25 picking up, the Es can link
    to TEP."

    An article about the Sun from IFLScience:

    https://www.iflscience.com/has-part-of-the-sun-really-become-broken-70653

    The latest from Dr. Tamitha Skov, WX6SWW:

    https://youtu.be/S2IOBwSo_LI

    Send your tips, reports, observations, questions, and comments to k7ra@arrl.net. When reporting observations, don't forget to tell us
    which mode you were operating.

    Also, check this article from September, 2002 QST:

    https://bit.ly/3Rc8Njt

    An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good
    information and tutorials on propagation are at http://k9la.us/ .

    Instructions for starting or ending email distribution of ARRL
    bulletins are at http://arrl.org/bulletins .

    Sunspot numbers for September 7 through 13, 2023 were 135, 123, 119,
    167, 173, 141, and 109, with a mean of 138.1. 10.7 cm flux was
    160.8, 160.9, 161.4, 163.9, 176.4, 153.5, and 142.6, with a mean of
    159.9. Estimated planetary A indices were 6, 6, 8, 4, 7, 25, and 17,
    with a mean of 10.4. Middle latitude A index was 11, 8, 12, 6, 8,
    17, and 17, with a mean of 11.3.
    NNNN
    /EX


    --- MBSE BBS v1.0.8.4 (Linux-x86_64)
    * Origin: American Radio Relay League (3:633/280.2@fidonet)
  • From ARRL@3:633/280.2 to All on Sat Sep 28 04:24:23 2024
    SB PROP @ ARL $ARLP037
    ARLP037 Propagation de K7RA

    ZCZC AP37
    QST de W1AW
    Propagation Forecast Bulletin 37 ARLP037
    From Tad Cook, K7RA
    Seattle, WA September 27, 2024
    To all radio amateurs

    SB PROP ARL ARLP037
    ARLP037 Propagation de K7RA

    Seven sunspot groups emerged this week. The first was on September 19, three
    on September 20, one each on September 22 and 23, and the last on September
    25.


    Average daily sunspot numbers increased from 120 to 137.2, and average daily solar flux shifted from 175.7 to 164.3.


    Geomagnetic numbers were much quieter. Average daily planetary A index
    changed from 35.7 to 14.3, and middle latitude A index from 23.4 to 10.7.


    Predicted solar flux is 180 September 27 to October 1, 190 on October 2-6,
    185 on October 7-9, 180 on October 10, 175 on October 11-16, 170 on October 17-18, 165 on October 19, 160 on October 20-23, 165 on October 24-26, then
    170 and 175 on October 27-28, 180 on October 29-30, and 190 on October 31 through November 2.


    Predicted planetary A index is 5 on September 27-28, 8 on September 29-30, 5
    on October 1-4, 10 on October 5-6, 5 on October 7-9, then 10, 20 and 19 on October 10-12, and 5 on October 13-21, 8 on October 22-23, 5 on October
    24-31, and 8 on November 1-2.


    "Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere
    - September 26, 2024 from OK1HH:


    "Solar flare activity is generally lower than it was in the first half of September, when M-class solar flares were common and X-class flares also occurred. The last significant M-class flare, including a CME, was observed
    on September 22. However, the Earth's magnetic field activity increased on September 25-26, incidentally in good agreement with the forecast.


    "Propagation conditions, especially in the shorter half of the shortwave
    range, have understandably improved, but not as much as we might have
    expected in the run-up to the equinox. This was influenced by a decrease in solar activity (compared to August levels) - and of course an increase in geomagnetic activity.


    "Unlike in times relatively recently past, any of us can monitor not only
    total solar activity, but also changes in solar wind parameters. Both its
    speed and the concentration of free electrons and protons ejected by flares. Changes in the ionosphere follow quickly, but not always in the same way. It
    is also always the result of previous developments."


    Latest report from Dr. Tamitha Skov, WX6SWW:
    https://youtu.be/B9jWbAVEpZw [ https://youtu.be/B9jWbAVEpZw ]

    Send your tips, reports, observations, questions and comments to
    k7ra@arrl.net [ mailto:k7ra@arrl.net ] . When reporting observations, don't forget to tell us which mode you were operating.


    For more information concerning shortwave radio propagation, see www.www.arrl.org/propagation [ http://www.arrl.org/propagation ] and the ARRL Technical Information Service web page at, www.arrl.org/propagation-of-rf-signals [ http://arrl.org/propagation-of-rf-signals ] .

    For an explanation of numbers used in this bulletin, see www.arrl.org/the-sun-the-earth-the-ionosphere [ http://arrl.org/the-sun-the-earth-the-ionosphere ] .


    An archive of past propagation bulletins is at www.arrl.org/w1aw-bulletins-archive-propagation [ http://arrl.org/w1aw-bulletins-archive-propagation ] .

    More good information and tutorials on propagation are at http://k9la.us/ [ http://k9la.us/ ] .


    Also, check this QST article:
    https://bit.ly/3Rc8Njt [ https://bit.ly/3Rc8Njt ] "Understanding Solar
    Indices" from September 2002 QST.


    Instructions for starting or ending email subscriptions to ARRL bulletins are at www.arrl.org/bulletins [ http://arrl.org/bulletins ] .


    Sunspot numbers for September 19 through 25 2024 were 109, 113, 117, 114,
    224, 123, and 160, with a mean of 137.1. 10.7 cm flux was 161.2, 153.8, 158, 162.8, 167.4, 172.4, and 174.2, with a mean of 164.3. Estimated planetary A indices were 20, 7, 6, 5, 13, 17, and 32, with a mean of 14.3. Middle
    latitude A Index was 15, 6, 6, 3, 9, 12, and 24, with a mean of 10.7.

    NNNN
    /EX

    ARRL® The National Association for Amateur Radio®
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    --- MBSE BBS v1.0.8.4 (Linux-x86_64)
    * Origin: American Radio Relay League (3:633/280.2@fidonet)