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ARRL Propagation Bulletin ARLP046 (2020)

SB PROP @ ARL $ARLP046
ARLP046 Propagation de K7RA

ZCZC AP46
QST de W1AW  
Propagation Forecast Bulletin 46  ARLP046
From Tad Cook, K7RA
Seattle, WA  November 13, 2020
To all radio amateurs 

SB PROP ARL ARLP046
ARLP046 Propagation de K7RA

The last time we experienced a day with no sunspots was October 13.
Prior to that, September 26 through October 8, September 24, and
August 21 through September 22 had no sunspots. Cycle 25 is clearly
underway and going strong.

Average daily sunspot number over the past reporting week, November
5 to 11 was 31.3, up from 21.3 in the previous seven days. Average
daily solar flux increased from 81.6 to 90. The higher HF bands are
opening up.

Geomagnetic indicators were very quiet, with average daily planetary
A index dropping from 6.3 to 4.4, and middle latitude A index (based
on readings from a single magnetometer on Wallops Island, Virginia)
from 4.9 to 2.7.

Predicted solar flux for the following seven days was revised
downward on Thursday, November 12. Predicted flux is 85 on November
13 to 15, 82 on November 16, 80 on November 17 to 19, 78 on November
20 to 25, then 80 and 82 on November 26 and 27, 86 on November 28
through December 5, then 90, 88, 86 and 84 on December 6 to 9, 82 on
December 10 and 11, 80 on December 12, 78 on December 13 to 22, 80
and 82 on December 23 and 24, and 86 on December 25 to 27.

Predicted planetary A index is 8 on November 13 to 15, 5 on November
16 to 19, then 15, 12 and 15 on November 20 to 22, then 8, 10 and 12
on November 23 to 25, 5 on November 26 through December 2, 8 on
December 3 and 4, 5 on December 5 to 8, then 8 and 10 on December 9
and 10, 5 on December 11 to 13, then 10, 5 and 10 on December 14 to
16, then 15, 12 and 15 on December 17 to 19, then 8, 10 and 12 on
December 20 to 22, then 5, 5, 8, 5 and 5 on December 23 to 27.

See https://bit.ly/38CfS6W for an article about increasing solar
activity.

Geomagnetic activity forecast for the period November 13 to December
9, 2020 from F. K. Janda, OK1HH.

"Geomagnetic field will be
Quiet on: November 13 and 14, December 1, 6 to 8
Quiet to unsettled on: November 15 to 19, 23 to 30, December 2, 4
Quiet to active on: December 3, 5, 9
Unsettled to active: November (20 to 22)
Active to disturbed: None
 
Solar wind will intensify on: November (18 to 20,) 21 to 25, (30,)
December (2,) 3  to 5, (9)

Parenthesis means lower probability of activity enhancement."

Mike Schaffer, KA3JAW of Easton, PA reported:

"Friday, November 6th was a good day for 10 meters, between
2000-2100 UTC, a wide regional swath between the North Pacific
Ocean, North America and Western Europe were all hearing call sign
prefixes of: 
CE/XR: Chile
CX: Uruguay
LU/LW: Argentina
PY: Brazil

Modes heard were CW, FT8, SSB.

Signal strength went from background noise level of 2 up to 9+ dB.
F2 distances ranged approximately from 3000 to 6000 miles (4828 to
9656 km). DXmaps on 28 MHz indicated the MUF reached 66 MHz above
grid square FN11 (Williamsport, PA) at 2009 UTC, then ramped up to
72 MHz above FN00 (Altoona, PA) at 2046 UTC.

Prior to local sunset at 2152 UTC, the F2 slowly faded out into the
South Pacific Ocean off the middle western coast of South America.

Five days later, November 11th:

Around 2130 to 2320 UTC both Sporadic-E (Es) and F2 started on the
11 meter band.

Background noise level ranged between 3 to 4 db.

Puerto Rico stations via Es were heard strong up to 20+ db with
light fades.

The following eight southern states were heard with signal
strength's ranging from 8 to 18 db: AL, AR, FL, GA, KY, LA, MS, TN.

At 2248 UTC the 10 meter band, FT8 mode was lightly active into AL
and TN til 2320 UTC when the DX finally dived under the 4 db noise
floor."

Useful images from the Solar Dynamics Observatory:

https://sdo.gsfc.nasa.gov/data/

Atlas Obscura on Hisako Koyama:

https://bit.ly/2Uu1Cod

For more information concerning 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 November 5 through 11, 2020 were 28, 35, 37, 40,
27, 27, and 25, with a mean of 31.3. 10.7 cm flux was 90.7, 93.8,
90.6, 90, 90, 86.8, and 88.1, with a mean of 90. Estimated planetary
A indices were 4, 8, 7, 5, 1, 2, and 4, with a mean of 4.4. Middle
latitude A index was 3, 7, 4, 3, 0, 0, and 2, with a mean of 2.7.
NNNN
/EX

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