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ARRL Propagation Bulletin ARLP049 (2019)

ARLP049 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 49  ARLP049
From Tad Cook, K7RA
Seattle, WA  December 6, 2019
To all radio amateurs 

ARLP049 Propagation de K7RA

No sunspots again this week. This run of zero sunspots has persisted
for over three weeks.
In last week's bulletin, we erroneously said that average daily
sunspot number for the week was 70.4, but as KB8W pointed out this
was the value of average daily solar flux. Average daily solar flux
for this week, November 28 through December 4, was 70.2.
Geomagnetic indicators were very quiet, with average planetary A
index declining from 8.3 to 3.4, while average mid-latitude A index
slipped from 5.7 to 2.
Predicted solar flux for the next 45 days is 70, in fact that is the
value forecast for every one of those days, all the way through
January 19.
Predicted planetary A index is 5 on December 6 and 7, then 8 on
December 8 and 9, 5 on December 10 to 17, then 12, 10, 8 and 8 on
December 18 to 21, 5 on December 22 to 29, 8 on December 30 and 31,
5 on January 1 to 3, 8 on January 4, 5 on January 5 to 8, 6 on
January 9, 5 on January 10 to 13, then 12, 10, 8 and 8 again on
January 14 to 17, and 5 on January 18 and 19. pointed out the Geminid meteor shower is coming up
soon, peaking December 13 and 14, just in time for the ARRL Ten
Meter Contest next week on December 14 and 15. Ionized meteor trails
may enhance 10 meter propagation.
This article from 2012 describes the source of the Geminids:
This year the full moon appears on December 12, which may interfere
with viewing the meteor shower.
F. K. Janda, OK1HH sent his geomagnetic activity forecast for the
period December 6 to 31, 2019
"Geomagnetic field will be: 
quiet on: December 12, 15 to 17, 23, 28 to 31 
quiet to unsettled on: December 9 to 11, 13, 24 to 27 
quiet to active on: December 6 to 8, 14, 18, 22 
unsettled to active on: December 21 
active to disturbed on: December (19 and 20)
Solar wind will intensify on: December (13 and 14, 16,) 18 to 21.
Parenthesis means lower probability of activity enhancement.
Everything suggests that we are very close to the minimum of the
11-year cycle now."
Updates on the Parker Solar Probe (thanks to Max White):
Thanks to David Moore for this on solar magnetic waves:
Jon Jones, N0JK reported on 6 meter sporadic-e on December 4:
"The winter sporadic-E season began with a strong, long lasting Es
opening across North America and the Caribbean December 4. Es first
appeared early around 1400z from W5 to W8, and lasted all day to
0040z December 5.
I was on from home (Lawrence, KS EM28) around 1830z and made a dozen
6 Meter FT8 contacts in Florida and Georgia.
Later while driving from Lawrence to Salina, stopped on highway 177
south of Manhattan, Kansas (EM18) and set up fixed mobile. 10 watts
and 1/4 wave magnet mount. Made 7 FT8 contacts in Florida, Georgia,
and Virginia. Was called by WA1EAZ FN42 and decoded WU1ITU FN65
several times. N0LL (EM09) decoded HH2AA, but no QSO. Other DX
spotted included TI5/N5BEK, XE1MEX, XE2AT, XE2JS, HI8DL, HI8PLE,
KP4EIT, HI8RD, NP3XF, NP4BM, and LU5FF Es - TEP by KW4BY."
The Royal Observatory of Belgium ( has
an interesting page showing sunspot number predictions for the next
12 months:
Thanks to Max White for this, on observing the ionosphere from
Found this on Galileo's sunspot drawings, presented as animation:
The ARRL 160 meter contest begins today at 2200 UTC. The predicted
quiet geomagnetic conditions are a good sign. See for details.
If you would like to make a comment or have a tip for our readers,
email the author at,
For more information concerning radio propagation, see and the ARRL Technical Information
Service 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
Monthly propagation charts between four USA regions and twelve
overseas locations are at
Instructions for starting or ending email distribution of ARRL
bulletins are at
Sunspot numbers for November 28 through December 4, 2019 were 0, 0,
0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 70.2, 69.8,
70.4, 71.2, 70.4, 69.9, and 69.6, with a mean of 70.2. Estimated
planetary A indices were 4, 5, 4, 4, 2, 2, and 3, with a mean of
3.4. Middle latitude A index was 2, 3, 2, 2, 2, 1, and 2, with a
mean of 2.


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