Register Account

Login Help

ARRL Propagation Bulletin ARLP011 (2020)

ARLP011 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 11  ARLP011
From Tad Cook, K7RA
Seattle, WA  March 13, 2020
To all radio amateurs 

ARLP011 Propagation de K7RA

I felt cheated this week when a much anticipated sunspot only
appeared just briefly, disappearing after two days.

Sunspot region AR2758 only appeared on March 8-9, with daily sunspot
numbers of 13 and 12. Average daily sunspot numbers for the week
rose from zero to 3.6, while average daily solar flux increased
(minimally) from 70 to 70.2.

Average daily planetary A index declined from 6.7 to 4.4, and
average middle latitude A index decreased from 4.6 to 3.6.

Predicted solar flux over the next 45 days is 70 on March 13-20, 72
on March 21-22, 70 on March 23 through April 4, 72 on April 5-18,
and 70 on April 19-26.

Predicted planetary A index is 5 on March 13-26, then 12 and 8 on
March 27-28, 5 on March 29 through April 5, then 10 and 8 on April
6-7, 5 on April 8-13, then 8, 12 and 8 on April 14-16, 5 on April
17-22, then 12 and 8 on April 23-24 and 5 on April 25-26.

The Vernal Equinox occurs next week, at 0350 UTC on March 20. 2020.
This is when the Southern and Northern Hemisphere are bathed in
approximately equal doses of solar radiation, and like the Autumnal
Equinox six months later, is considered a good time of year for long
distance HF communications.

I see some new activity over the solar horizon, an active, bright
spot, but this time in the Northern Hemisphere:

Geomagnetic activity forecast for the period March 13 to April 8,
2020 from OK1HH.

"Geomagnetic field will be: 
quiet on: March 13-14, 23-25, 29-30. 
quiet to unsettled on: March 15, 18 (- 21), 26, 28, April 2-7. 
quiet to active on: (March 22, 31, April 1, 8). 
unsettled to active on: (March 16-17, 27). 
active to disturbed: None.

"Solar wind will intensify on: March (17-22,) 28, (29-31).
- Parenthesis means lower probability of activity enhancement. 
- The predictability of changes remains lower at present. 
- Beware of paraskavedekatriafobia on Friday!"

Ken, N4SO reports monitoring NCDXF 15 meter beacons using a
half-square antenna.

"CS3B on 21.150 MHZ NCDXF Beacon. Location for CS3B is Madeira.
(Northwest coast of Africa)

"CS3B heard on March 4, 2020, 1931 UTC, and 1934 UTC.

"The beacons in the NCDXF International Beacon Project broadcast on
four different power levels-- 100 watts, 10, 1 and 100 mw, giving a
very good indication of propagation quality.

"I heard the very strong CS3B beacon on at least 3 power levels.  The
last one is uncertain.

"It's not unusual to hear NCDXF beacons on 3 power levels, if the
signal is strong and the frequency is quiet.

"Other NCDXF beacons heard daily on 21.150 MHZ are OA4B and YV5B with
variable signals, or not at all. But often heard approximately at
1900, 2000, or 2100 UTC."

Steve Gardner, KB1RUV noted strong 15 meter activity into the
Caribbean last Saturday.

A local newspaper article in Duluth about recent sunspot activity
can be found here:

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, 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 March 5 through 11, 2020 were 0, 0, 0, 13, 12,
0, and 0, with a mean of 3.6. 10.7 cm flux was 69.5, 70, 69.9, 70.2,
70.8, 70.8, and 70.5, with a mean of 70.2. Estimated planetary A
indices were 4, 5, 5, 5, 5, 4, and 3, with a mean of 4.4. Middle
latitude A index was 3, 4, 5, 3, 5, 3, and 2, with a mean of 3.6.


Instragram     Facebook     Twitter     YouTube     LinkedIn