ARLP024 Propagation de K7RA

 

SB PROP @ ARL $ARLP024

ARLP024 Propagation de K7RA

 

ZCZC AP24

QST de W1AW

Propagation Forecast Bulletin 24 ARLP024

From Tad Cook, K7RA

Seattle, WA June 28, 2024

To all radio amateurs

 

SB PROP ARL ARLP024

ARLP024 Propagation de K7RA

 

ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0538UTC/28 JUNE 2024

BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE:

 

"A glancing blow from a recent CME is expected to arrive late on UT day 28-Jun. Additional to this, solar wind parameter Bz has been oriented southward for approximately 15 hours. Combined this may induce G1 geomagnetic conditions. A second CME is expected to arrive late on UT day 29-Jun and may also cause G1 geomagnetic conditions.

 

"INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS

EJECTION FROM 28-29 JUNE 2024."

 

Nine new sunspot groups emerged over this reporting week, June 20-26.

 

Two appeared on June 21, four on June 23, two more on June 25 and one on June 26.

 

Average daily sunspot number declined from 149.6 to 141.6, but average daily solar flux increased from 178 to 195.1.

 

Average planetary A index declined from 10.3 to 7.

 

Predicted solar flux for the near term is 182 on June 28-30, then 180, 185, 180, 175, and 190 on July 1-5, 180 on July 6-7, then 165, 165 and 180 on July 8-10, 170 on July 11-13, then 180, 190 and 195 on July 14-16, then 200 on July 17-18, 195 on July 19-20, 190 on

July 21-28, then 195, 190, 185 and 190 on July 29 through August 1, and 180 on August 2-3.

 

Predicted planetary A index is 12 and 15 on June 28-29, 5 on June 30 through July 13, then 10, 10 and 8 on July 14-16, 5 on July 17-19, 8 on July 20, then 5 on July 21-26, 8 on July 27-28, and 5 on July 29 to August 9.

 

Geomagnetic activity forecast for the period June 28 - July 04, 2024, from Tomas Bayer, RWC Prague, Institute of Geophysics of the ASCR, Prague, Department of Geomagnetism Budkov observatory (BDV):

 

"Quiet: June 30 to July 1, 3 and 4

 

"Unsettled: June 28 and 29, July 1 and 2

 

"Active: possible June 28 and 29, July 2

 

"Minor storm: 0

 

"Major storm: 0

 

"Severe storm: 0

 

"Next week, we expect quiet to unsettled conditions. Two unsettled to active events are possible next week.

 

"The first one is possible about June 28 - 29, and the other one, but unlikely, about July 2. Other days, we expect quiet to unsettled conditions."

 

George Hoffman, W7POE, wrote in an email:

 

"A question some of us have is, with the quite high SFI and SSN numbers, why is the MUF around the Washington state region never much above 21 MHz these days? For me 10 meters was totally dead

during Field Day. I haven't seen MUFs in the 30 MHz region for several weeks now. Wonder if you could shed some light on this puzzling issue. Thanks."

 

I replied that I suspect this is because of seasonal variation.

 

I used the W6ELprop program to estimate MUF over a specific path (Dallas, Texas from Seattle) with an estimated smoothed sunspot number of 133.

 

For the current date (June 27) it shows the MUF at about 22 MHz, day and night.

 

But when I change the date back closer to the Spring Equinox (just before March 28), the MUF is highest from 2030-2100 UTC at 34.7 MHz.

 

It also shows MUF above 28 MHz from 1530-0230 UTC.

 

George also shared a very useful link:

 

George replied:

 

"I also just ran W6ELprop and got 22 MHz for the Burien to Dallas path and 17.6 MHz for the Burien to New York path. Anyway, I will wait around for 10 meter openings. Thanks again."

 

William Paul, KD6JUI, of Dixon, California wrote in an email:

 

"I was operating from my kayak again on Field Day. 10 watts into a homebrew loop. My ops were all SSB.

 

"Only heard one (1!) station on 10m, so all my operating was confined to 15m. I had enough exchanges to keep me happy but there was a lot of fading. Didn't hear any foreign stations coming in.

 

"Did get some fine photos of bees pollinating water flowers.

 

"Maybe if Field Day were held in December and with the same high solar flux, 15 and 10 meters would've been a lot more active."

 

K7RA comment: There is Winter Field Day in January.

 

NASA images:

 

Solar max and climate:

 

Active sunspot returns:

 

Big sunspot:

 

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

 

For more information concerning shortwave radio propagation, see and the ARRL Technical Information Service web page at . For an explanation of numbers used in this bulletin, see

.

 

An archive of past propagation bulletins is at

.

 

More good information and tutorials on propagation are at .

 

Also, check this QST article about Solar Indices:

 

Instructions for starting or ending email distribution of ARRL bulletins are at .

 

Sunspot numbers for June 20 through 26 2024 were 138, 133, 139, 176, 141, 129, and 135, with a mean of 149.6. 10.7 cm flux was 203.3, 196.9, 195.7, 195.8, 198.7, 193.7, and 181.4, with a mean of 178. Estimated planetary A indices were 7, 5, 4, 10, 5, 9, and 9, with a mean of 10.3. Middle latitude A index was 8, 4, 6, 12, 7, 9, and 8, with a mean of 10.1.

NNNN

/EX

 



 



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