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ARRL Propagation Bulletin ARLP051 (2019)

ARLP051 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 51  ARLP051
From Tad Cook, K7RA
Seattle, WA  December 20, 2019
To all radio amateurs 

ARLP051 Propagation de K7RA

Still no sunspots, and it's been the same for 37 consecutive days.

Geomagnetic conditions remained quiet, until "a minor stream of
solar wind" (according to hit us on December 18.
This drove the planetary A index to 13 from the low single digit
values earlier in the week.

Average planetary A index for December 12-18 rose to 4.6, from 3.7
over the previous 7 days, while mid-latitude A index increased from
1.9 to 4.

Predicted solar flux over the next 45 days is 70, and we've seen
this same daily 45-day flux forecast since December 2. December 1
was the last time there was any value in the forecast other than 70
when they predicted 69 for December 23 through January 4. The
forecast is updated daily at .

Predicted planetary A index from the same forecast is 8 on December
20-21, 5 on December 22 through January 4, 8 on January 5, 5 on
January 6-8, 8 on January 9-10, 5 on January 11-13, 12 on January
14, 10 on January 15-17, 5 on January 18-31, 8 on February 1, and 5
on January 2.

Geomagnetic activity forecast for the period December 20, 2019 til
January 15, 2020 from OK1HH.

"Geomagnetic field will be
Quiet on: December 28-31, January 1-4, 8
Quiet to unsettled on: December 21-27, January 7, 9-13
Quiet to active on: (December 20, January 5-6)
Unsettled to active on: (January 14-15)
There are no disturbed conditions in this forecast.

"Solar wind will intensify on: January (14,) 15 (-16)

"- Parenthesis means lower probability of activity enhancement.
- Everything suggests that we are very close to the minimum of the
11-year cycle at present stage of development."

Naturally because of weak solar activity, the 10 meter contest last
weekend was rather slow.

Jon Jones, N0JK from Kansas wrote:

"With a solar flux of 70 and a low K index, not much F-layer
propagation was expected in the 2019 ARRL 10 M contest.

"But Sunday afternoon I found a strong 10 Meter opening to Argentina
and Chile from Kansas.

"I set up 'fixed mobile' with 5 watts and a 1/4 wave whip on the car
around 1800z December 15. I didn't expect much, but heard several
very loud stations from South America on CW. I put CE2ML and LW8DQ
in the log. Signals were up to 599.

"I wonder if this was a 'Es - TEP' opening?

"When I got home, I checked DXMaps. It showed what appeared to be an
Es cloud over Louisiana.

"This may have supported 10 Meter propagation on to CE and LU. Es can
raise the MUF when the signal hits the F-Layer and are often strong.

"A nice treat for an otherwise slow 10 Meter Contest."

Here at K7RA using a very limited low elevation random wire antenna,
I checked 10 meters in the last hour of the contest on Sunday
looking to hand out a few QSOs. I heard no local stations here in
the Seattle area on SSB, but did manage to work some CW operators.

N8II reported to the forum (excerpts):

"The F2 opening to the south was much better Saturday. The Geminids
meteor shower did coincide with the contest this year which saved
the day especially for the big guns.

"Friday, Saturday morning and evening, and Sunday morning I was able
to work meteor scatter on CW in all directions and there was some
activity from most of the states/provinces within the approximate
1500 mile MS range. For example, I worked all W1 except RI and all
of eastern Canada except NL, PE and NU. I worked 4 NB stations,
about 1-2 via brief sporadic-E.

"There was a short sporadic-E opening late Sunday around 2127-2205Z
to TX, AR, IA but again activity was low. Sunday was a real grinder
with most stations already worked. The meteor scatter died out
around 1600Z Sunday. F2 was limited to Brazil and Chile here from
2016-2057Z. It was difficult to work PY even when above S5 here; I
guess many locations in PY have high noise levels."

New forecast from Dr. Tamitha Skov, WX6SWW:

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 web page at, 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 December 12 through 18, 2019 were 0, 0, 0, 0, 0,
0, and 0, with a mean of 0. 10.7 cm flux was 70.5, 68.9, 70.3, 71,
70, 70.5, and 70.2, with a mean of 70.2. Estimated planetary A
indices were 4, 4, 3, 5, 1, 2, and 13, with a mean of 4.6. Middle
latitude A index was 3, 3, 2, 5, 1, 2, and 12, with a mean of 4.