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  • ARLP020 Propagation de K7RA

    From ARRL Web site@3:633/280.2 to All on Sat May 20 05:29:33 2023
    SB PROP @ ARL $ARLP020
    ARLP020 Propagation de K7RA

    ZCZC AP20
    QST de W1AW
    Propagation Forecast Bulletin 20 ARLP020
    From Tad Cook, K7RA
    Seattle, WA May 19, 2023
    To all radio amateurs

    SB PROP ARL ARLP020
    ARLP020 Propagation de K7RA

    This reporting week, May 11-17, average daily sunspot number was
    nearly the same as last week, 118.6 compared to 119.3, only
    marginally lower.

    But average daily solar flux dropped from 167.8 to 143.2.

    Geomagnetic indicators were quieter, both planetary and middle
    latitude A index at 9.6. Last week the two numbers were 15.1 and
    11.9, respectively.

    What is the outlook for the next few weeks?

    10.7 cm solar flux is forecast to have a peak of 165 on June 8.

    The predicted numbers are 145 on May 19, 140 on May 20-21, 135 on
    May 22-24, 140 on May 25-26, 145 on May 27, 155 on May 28-30, 160 on
    May 31 and June 1, 155 on June 2-3, 160 on June 4-7, then 165, 160,
    150, 145, and 150 on June 8-12, then 155 on June 13-17, 150 on June
    18, 145 on June 19-21, 140 and 145 on June 22-23, and 155 on June
    24-26 then 160 on June 27-28.

    Predicted planetary A index is 5, 8, 12, 15 and 5 on May 19-23, 12
    on May 24-25, 15 on May 26, 10 on May 27-28, 8 on May 29, 5 on May
    30 through June 1, then 16, 12, 16 and 12 on June 2-5, 8 on June
    6-8, then 5 on June 9-18, 12 and 20 on June 19-20, 15 on June 21-22,
    10 on June 23-24, 8 on June 25, and 5 on June 26-28.

    These numbers are updated daily here:

    https://services.swpc.noaa.gov/text/45-day-ap-forecast.txt

    Thanks to reader David Moore for this:

    "How 1,000 undergraduates helped solve an enduring mystery about the
    Sun:

    "https://www.sciencedaily.com/releases/2023/05/230509122026.htm

    "For three years at the height of the COVID-19 pandemic, a group of
    students spent an estimated 56,000 hours analyzing the behavior of
    hundreds of solar flares. Their results could help astrophysicists
    understand how the Sun's corona reaches temperatures of millions of
    degrees Fahrenheit."

    Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
    Ionosphere - May 18, 2023, from F.K. Janda, OK1HH.

    "On May 12, we expected a CME impact from the flare on the evening
    of May 9. It was indeed registered - at 0635 UTC the geomagnetic
    storm began. However, it was weaker than expected, of G1 class.

    "On 13 May at 1915 UTC, an unexpected CME impact followed for a
    change, which again triggered another G1 class geomagnetic storm.

    "On 16 May, we expected another smaller CME. The particle cloud has
    been slowly approaching Earth since the magnetic filament eruption
    in the southern hemisphere of the Sun on 12 May.

    "The next solar flare on May 16, with a maximum at 1643 UTC, was
    M9.6 class. It came from a sunspot group still hiding behind the
    southeastern limb of the Sun. In fact, it may have been an X flare,
    partially obscured by the solar horizon. Yet it caused the strong
    Dellinger effect (shortwave fade) over North America. After the
    sunspot group came out on the solar disk, we could observe it as AR
    3310. It's about three times wider than Earth, and its magnetic
    configuration promises more flares.

    "Not only was solar flare activity quite high, but the Sun was
    hurling so many CMEs into space that hardly a day went by without
    one hitting Earth. Therefore, the frequency of geomagnetic storms
    was also higher, followed by frequent deterioration of shortwave
    propagation conditions. In summary, the 25th solar cycle continues
    to evolve nicely."

    Frank, VO1HP sent this from St. Johns, Newfoundland:

    "On May 12 1957-2113 UTC, there was a strong 6M Es opening into mid
    South America. Logged 20 stations using FT8. No CW or SSB heard.
    Stations worked at VO1HP remote station: LU3CQ, CE3SX, 2SV, LI7DUE,
    9AEA, 9DO, 1FAM, 8EX, CX3VB, PP5BK, LU2DPW, CX1VH, PU3AMB, CX6VM,
    LU3FAP, XQ3SK, XQ3MCC, CE3VRT, 3SOC, and LU5FF.

    "Antenna 4el Yagi at 35ft overlooking ocean. K3 + PR6, KPA500
    KAT500. Other VO1s seen: VO1CH, VO1SIX, and VO1AW."

    On April 24, Rocky Riggs, W6RJK in Truckee, California wrote:

    "I was not very active until recently when I was introduced to POTA.
    The park I frequent the most would typically give me 40-60 contacts
    in a 2 hour period.

    "On Monday, April 24th, I went to the same park, and in 30+ minutes
    had no contacts and couldn't hear anyone either. I later found out
    that the solar storm was causing most of our radio problems. Until
    then, I had never considered much about solar flares, or how the Sun
    influences radio propagation. Now, finally, I'm trying to learn as
    much as I can. The K7RA Solar Update in the ARRL Newsletter is
    FANTASTIC and will be my source going forward to help me learn and
    understand.

    "Here's my question. Is there a 'real time' place where I can go to
    determine if a particular band has good propagation (I typically use
    20m and 40m)?

    "You know, like before I go out and get all set up and it's a 'goose
    egg.'"

    As I first reported in Propagation Forecast Bulletin ARLP017, I told
    him that a very useful tool (to use) is to check real time
    geomagnetic indices with this:

    https://www.swpc.noaa.gov/products/planetary-k-index

    Nice quiet conditions show a planetary A index at 1 or 2, unsettled
    conditions at 3, then above 3 conditions are disturbed. The scale is logarithmic, so each point in either direction is important.

    Another approach is to use pskreporter at https://www.pskreporter.info/pskmap.html which is handy if you live
    in a grid square that has many active hams, or a nearby grid that is
    more populated.

    You can check FT8 activity on any band. There is also a "Country of
    Callsign" selection so you can check activity across your nation of
    choice. Recently when I have raised nobody on 10 meter FT8 this
    option showed no activity here in the Pacific Northwest but plenty
    of 10 meter activity in the southeast United States.

    Here is a new video from Dr. Tamitha Skov, WX6SWW:

    https://youtu.be/xSQYjH6D_YA

    NASA sunspot picture:

    https://bit.ly/458DrPw

    A video of a recent eruption:

    https://www.youtube.com/watch?v=Rm7M5pqjCgY

    Here are articles about Radio Blackout:

    https://bit.ly/434c5bw

    https://bit.ly/3pWId2e

    https://bit.ly/45hXTxh

    https://bit.ly/3MEkCwa

    NASA warning of a Solar Storm threat:

    https://bit.ly/3pSK4p2

    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.

    For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information
    Service at http://arrl.org/propagation-of-rf-signals . For an
    explanation of 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 . 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 May 11 through 17, 2023 were 152, 134, 120, 109,
    103, 106, and 106, with a mean of 118.6. 10.7 cm flux was 163.4,
    149.1, 143.8, 139.7, 134.5, 134.3, and 137.9, with a mean of 143.2.
    Estimated planetary A indices were 9, 19, 13, 8, 6, 8, and 4, with a
    mean of 9.6. Middle latitude A index was 10, 15, 12, 9, 6, 10, and
    5, with a mean of 9.6.
    NNNN
    /EX


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    * Origin: American Radio Relay League (3:633/280.2@fidonet)