May 18 was the last day we saw sunspot activity, after more than two weeks with daily sunspots visible. Average daily sunspot number declined to 5.3 this week following 22.7 during the previous week. Average daily solar flux declined from 75.7 to 69.8.
Geomagnetic conditions were quieter, with average daily planetary A index declining from 13 to 5.
Predicted solar flux over the next 45 days is 67 on May 24-31, 74 on June 1, 76 on June 2-10, 74 on June 11, 72 on June 12-13, 70 on June 14-15, 69 on June 16-17, 68 on June 18, 67 on June 19-25, 70, 72 and 74 on June 26-28, then 76 on June 29 through July 7.
Predicted planetary A index is 5 on May 24, 8 on May 25, 5 on May 26-27, then 10, 12, 8 and 8 on May 28-31, 5 on June 1-15, 8 on June 16-18, 5 on June 19-23, then 10, 12, 8 and 10 on June 24-27, and 5 on June 28 through July 7.
Geomagnetic activity forecast for the period May 24-June 19, 2019 from F.K. Janda, OK1HH.
Geomagnetic field will be:
Quiet on May 27, June 2, 4-5, 14-15, 18
Quiet to unsettled on May 25-26, June 1, 6, 9-10, 17, 19
Quiet to active on May 24, 30-31, June 3, 7-8, 12-13, 16
Unsettled to active on May 28-29
Active to disturbed on June (11)
Solar wind will intensify on May 29-31, June 1, (10-12)
Parenthesis means lower probability of activity enhancement.
On May 20, Markus Hansen, VE7CA, wrote: “Today I have been hearing many California beacons on 10 meters as well as K7EMX/B in Utah. So, I have been calling CQ on 28005.00 for several hours and not one single answer to my calls.
“I have also been listening to AE6RQ’s SDR and my signal has been between 579 and 20 over S 9 from 1700 to 2100Z. I don’t have a 6-meter antenna up right now, but I wish I did.
“I appreciate your propagation reports. I copy them regularly on CW via W1AW.”
Max White, M0VNG, sent this piece on Earth’s moving magnetic North Pole: https://bit.ly/2HC1j4e
Scott Avery, WA6LIE, in Salinas, California reported a nice sporadic E opening on 6 meters during Mother’s Day, May 12. “We had a good opening from 1430-2030 UTC here in Salinas CM96. Had a lot of FT8 activity logging 45 contacts there and 6 QSOs on SSB.
“Conditions were wild for a bit on SSB with multiple QSO’s on the same frequency i.e.: 50.130, 50.135 etc. That lasted for about 2 hours after about 1600z.
“I worked all I heard and worked many grid squares! The magic band… got to love it!”
K9LA recently updated a 2007 article he wrote for WorldRadio on ionospheric sounders, which were referenced in recent bulletin ARLP019. See https://k9la.us/Measuring_the_Ionosphere.pdf. The link to data from ionospheric sounders provided in ARLP019 is here: https://metrics.af7ti.com/. Note that you can re-order the table by clicking on any of the headings. For instance, at 0740 UTC on May 17 if I click on the foF2 column, I can sort the ionosondes by foF2 values and discover that the ionosonde on Cocos Island has the highest foF2 value, at 10.465 MHz. Number 2 is Guam at 8.588 MHz, followed by Rome, Italy. Later at 0850 UTC those values were 11.56 MHz, 8.6 MHz and 6.95 MHz. In only an hour, propagation changes!
The latest video from Dr. Skov: https://youtu.be/hKDyUd1RC5Q
This weekend is the CQWW WPX contest, details here: https://www.cqwpx.com/
If you would like to make a comment or have a tip for our readers, email the author at email@example.com.
For more information concerning radio propagation, see 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/.
Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation. Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins.
Sunspot numbers for May 16 through 22, 2019 were 13, 13, 11, 0, 0, 0, and 0, with a mean of 5.3. 10.7 cm flux was 73.6, 72.1, 70.6, 68, 68.7, 68, and 67.3, with a mean of 69.8. Estimated planetary A indices were 8, 5, 5, 3, 6, 4, and 4, with a mean of 5. Middle latitude A index was 9, 7, 8, 3, 7, 4, and 5, with a mean of 6.1.
The XPA125B amplifier has a gain of 13 dB making it the perfect amplifier for a 5 watt transmitter when 100 watt output is needed. The automatic Antenna Tuner Unit and power amplifier unit of XPA125B can be used independently of each other... Read more