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The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: We just witnessed 5 days in a row with zero sunspots, but on February 2 a small sunspot group (2801) appeared on our sun’s northwest limb. It soon rotated off the sun’s visible area, and on February 4, the sunspot number was back to zero.

We will probably see a few more days with no sunspots, but a return after February 11 is possible, when increased solar flux is forecast.

Average daily sunspot numbers declined from 28.1 reported in last week’s bulletin ARLP005 to 3.3 this week. Average daily solar flux dropped 3 points from 77.2 to 74.2. Average daily planetary A index went from 9.4 to 6.7.

Solar flux over the next 30 days is predicted at 74 on February 5 – 11; 76 on February 12 – 16; 78 on February 17 – 22; 76 on February 23 – 25; 74 on February 26; 73 on February 27 – March 1, and 72 on March 2 – 7.

Predicted planetary A index is 5, 8, 16, and 10 on February 5 – 8; 8 on February 9 – 10; 5 on February 11 – 20; 20, 16, and 12 on February 21 – 23; 5 on February 24–27; 18, 12, and 8 on February 28 – March 2; 5 on March 3 – 5, and 10 on March 6 – 7. A coronal hole may return on March 20 – 21 causing a rising A index.

Here’s the geomagnetic activity forecast for February 5 – March 2 from F.K. Janda, OK1HH. The geomagnetic field will be:

quiet on February 18 – 19, 26 – 27
quiet to unsettled on February 5 – 6, 9 – 13, 17, 24 – 25
quiet to active on February 7 – 8 , 14 – 16, 20, 23, 28
unsettled to active February 21 – 22, March 1 – 2
active to disturbed nothing predicted
solar wind will intensify on February (8 – 10, 15 – 17, 20 – 22,) 23 – 24, (25 – 28)

Notes: Parentheses mean lower probability of activity enhancement.

Predictability of changes remains low, as indications remain ambiguous.

Jon Jones, N0JK, reported, “Had some sporadic-E on 50 MHz the evening of February 1 (February 2 UTC). XE2TT (DL44) in on 50.313 MHz, 0205 UTC. Was on Saturday night for a couple of hours January 31 UTC for the CQ 160-Meter CW Contest. Band noisy due to snow and high winds in eastern Kansas. Made over 50 contacts with 5 W and a rain gutter antenna.”

More from Jon the next day: “Some sporadic-E on 6 meters February 2 – 4. Es is rare in February. I worked WA2VJL (EL16) on 50.313 MHz FT8 from my mobile setup on February 2.

N0LL (EM09) is back on 6 meters after repairing storm damage to his antenna. On February 3 Larry worked XE2ML on 6 meters. VK3OER in Australia spotted K0TPP in Missouri. Possible sporadic-E-TEP across the Pacific Ocean.

XE2ML 21/02/04 0010Z 50313.0 EM09<ES>DL74 N0LL

N0LL 21/02/04 0009Z 50313.0 DL74QB EM09 TNX QSO XE2ML

Had some Es when I checked from my car at work. Decoded XE2OR, N7WB/p, K0JY, and XE2ML.

N7WB/P 21/02/03 2354Z 50313.0 EM28IX ES DM51BI N0JK

VK3OER spotted K0TPP.

K0TPP 21/02/04 0036Z 50313.0 -16 CQ K0TPP correct! VK3OER

In response to last week’s bulletin and the subject of super-huge solar flares, Jon commented, “The VHF community is ready. Bring it on!”

This article in Physics Today discusses solar magnetic waves and corona composition:

Here’s the latest report from Space Weather Woman Tamitha Skov, WX6SWW.

An audio tour of the Sunspot, New Mexico, solar observatory.

Sunspot numbers for January 28 – February 3 were 0, 0, 0, 0, 0, 12, and 11, with a mean of 28.1. The 10.7-centimeter flux was 75.6, 75.5, 73.7, 73.4, 73.7, 72.9, and 74.3, with a mean of 77.2. Estimated planetary A indices were 5, 3, 2, 1, 5, 17, and 14, with a mean of 9.4. Middle latitude A index was 3, 2, 2, 0, 4, 11, and 10, with a mean of 6.3.

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check out K9LA’s Propagation Page.

A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

Instructions for starting or ending email distribution of ARRL bulletins are on the ARRL website. (arrl.org)

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