No sunspots this week, and as of Wednesday we’ve seen 15 spotless days in a row. This is the solar minimum. The current Solar Cycle (24) is expected to end by the end of this calendar year.

Average daily solar flux declined from 69.4 to 68.1. Average daily planetary A index declined slightly from 8.9 to 8.3, but average daily mid-latitude A index rose from 7.7 to 8.

Predicted solar flux is 68 on September 20-26, 69 on September 27 through October 6, 70 on October 7, 68 on October 8-19, 69 on October 20 through November 2 and 70 on October 3.

Predicted planetary A index is 5 on September 20-21, 8 on September 22-23, 5 on September 24-25, then 10, 35, 45, 20 and 10 on September 26-30, then 8, 10 and 8 on October 1-3, then 5, 5 and 12 on October 4-6, 5 on October 7-9, then 8, 5 and 8 on October 10-12, then 5, 8 and 10 on October 13-15, 5 on October 16-19, then 8, 5 and 5 on October 20-22, then 8, 25, 30, and 18 on October 23-26, then 8, 5 and 8 on October 27-29, 5 on October 30 through November 1, 12 on November 2 and 5 on November 3.

Geomagnetic activity forecast for the period September 20 until October 14, 2019 from F.K. Janda, OK1HH.

Geomagnetic field will be
Quiet on: September 20 (-21,) October 7-8
Quiet to unsettled on: September 22, (24,) October 4-6, 9-10
Quiet to active on: September 23, 25, 30, October 1-3, 11
Unsettled to active on: September (26), October (12-14)
Active to disturbed: September (27-29)

Solar wind will intensify on: September (24-27,) 28-30.
October 1 (-4, 7-9,) 11 (-14)

- Parenthesis means lower probability of activity enhancement.
- The predictability of changes remains lower.

Another explanation for heliophysics. Thanks to W4NI: https://bit.ly/2kVU7s5

Jon Jones, N0JK, in Kansas sent this: “Six-meter Es made an appearance in the ARRL September VHF Contest Saturday evening (September 15 UTC). Starting around 0030z, stations in Arizona, California, Nevada and Utah appeared and worked stations in the Midwest states. I even saw a few double hop sporadic-E contacts between Michigan to Nevada, and California to Alabama. I made about a dozen FT8 6-meter contacts running 10 W and a 2-element Yagi antenna in the single operator portable category in the opening. My best DX was NA6L (DM03) in southern California.
“Sporadic-E propagation is rare in September, and it was a special treat to have an Es opening during the VHF Contest."

Another 6 meter report, from KD7WPJ in Mountain House, California, which is between Tracy and Livermore: “During ARRL September VHF Contest I made 50 MHz FT8 contact with VE7DAY on September 16 at 0242 UTC. I used only 10 W with a simple dipole antenna. The distance is approximately 844 miles.

It kind of late for Es season, and the propagation mechanism is undetermined.”

Ken, N4SO, in Alabama sent this regarding signals copied on September 13: http://www.astrosurf.com/luxorion/qsl-propa5.htm. "This web site on Grey Line propagation explains why on many days on 18.100 MHZ, FT8 mode, Japan, Australia or Fiji are decoded.  This example is starting at 2236 UTC and lasts for an hour or more.  This shows JQ1TIV easily worked at 2330 UTC.  (Power levels were at about 15 W to a Half Square antenna.)

“Late afternoon hours at around 5 PM/2200 UTC start time, usually 2 hours before local sunset.

223630 -17  0.2  938  CQ VK2IZ QG60         Australia
223600  -7  0.1  259  CQ 3D2AG RH91         Fiji
233000 -11  0.1 2439  N4SO JQ1TIV RR73   Japan
233015  Tx      2432  JQ1TIV N4SO 73
233415   8  0.1  845  HK0RMR EK92     San Andres & Providencia"

KC9WIR cc'd a message he sent to VK3CRG on September 14: "At 0810 UTC it was 3:10 AM in Chicago (CDT). I was sleeping, but my radio was in receive-only mode on the WSPR frequency on 40 meters and my PC was decoding WSPR signals. This morning I looked what I harvested during the night and there was your signal clocked at 0812 UTC. That’s nice, given that you only used 5 W! You were -20 dB in Chicago. Conditions were poor; the maximum distances of most other logged stations were between 400- and 2000-miles during nighttime. It's puzzling how your QRP signal made it here."

If you would like to make a comment or have a tip for our readers, email the author at k7ra@arrl.net.

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 September 12 through 18, 2019 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 69.4, 68.3, 68.6, 67.7, 68.7, 67.5, and 66.3, with a mean of 68.1. Estimated planetary A indices were 7, 8, 6, 8, 11, 9, and 9, with a mean of 8.3. Middle latitude A index was 7, 8, 7, 8, 10, 8, and 8, with a mean of 8.