SB PROP @ ARL $ARLP014
ARLP014 Propagation de K7RA
QST de W1AW
Propagation Forecast Bulletin 14 ARLP014
From Tad Cook, K7RA
Seattle, WA April 8, 2022
To all radio amateurs
SB PROP ARL ARLP014
ARLP014 Propagation de K7RA
Lots of solar activity livened up HF conditions over the past
reporting week, March 31 to April 6. Average daily sunspot number
rose from 90.1 to 94.6, and daily solar flux from 132.7 to 135.3.
It looks like solar flux may peak this month at 140 on April 24-28.
Since March 18 we were unable to get daily solar flux from the
observatory in Penticton, British Columbia, so for a couple of weeks
we relied on secondary sources which were all in whole numbers,
instead of resolving to 0.1. Multiple inquiries to the observatory
led nowhere, but now the data is back online at,
I had to fudge the flux value for March 31, because the value of
239.5 was obviously an error, probably due to a CME overwhelming the
10.7 cm receiver at the observatory, so I averaged the morning and
afternoon readings to 149.3. The official daily flux value is always
from the 2000 UTC local noon reading.
Geomagnetic conditions were quite active on March 31 through April
2. Average daily planetary A index for the week increased from 10 to
14.4, and middle latitude A index from 8.1 to 10.9.
Spaceweather.com reported 146 solar flares over the month of March
and predicts even more for April. They also report that Solar Cycle
25 is progressing faster and stronger than earlier predictions.
A new sunspot group appeared on March 31, two more on April 1,
another on April 2 and one more on April 3, and one more on April 5.
Predicted solar flux is 108 on April 8-9, 105 on April 10-11, 100 on
April 12-14, then 110, 115 and 120 on April 15-17, 125 on April
18-19, 130 on April 20-23, 140 on April 24-28, 135 on April 29-30,
130 on May 1, 120 on May 2-3, 125 on May 4-5, 120 on May 6, 115 on
May 7-8, 110 on May 8-9, 115 on May 11, and 120 on May 12-14.
Predicted planetary A index is 12, 15, 10 and 8 on April 8-11, 5 on
April 12-19, 10 on April 20-21, then 5, 15, 10 and 8 on April 22-25,
5 on April 26-28, then 18, 12, 10 and 8 on April 29 through May 2, 5
on May 3-7, then 12 and 10 on May 8-9, and 5 on May 10-16.
Solar wind in the news:
F.K. Janda, OK1HH reports:
"Total solar activity has been declining. Recent CMEs generated by
solar flares have usually not been headed to Earth. In particular,
on April 6, the solar wind was expected to intensify from a CME
generated by a filament eruption on April 3rd, but only a small
portion of the solar plasma cloud reached Earth.
"The Earth's magnetic field was unsettled to active until April 2
and partly on April 4 and 7. The increased geomagnetic activity on
the night of April 3 to 4 worsened diurnal short wave propagation
conditions on April 4. Thereafter, despite the continuing decline in
solar activity, shortwave propagation conditions improved.
"In further development, we first expect a decline in solar
activity. Its growth in the second half of the month will again
cause an improvement of shortwave propagation. However, the
development will be slightly irregular."
Another great video forecast from Dr. Tamitha Skov, WX6SWW, the
Space Weather Woman:
WB8VLC reports from Oregon:
"Another great week on 10 meters but only SSB/CW and not much FM
activity, but the activity was very strong with signals to South
Africa, Taiwan, Philippines, Norfolk Island, and Australia.
"Interesting that I have not heard any European stations during any
morning or afternoon openings to the east, just South Africa."
A small portion of his log:
"April 3 it was ZS in the morning and VK at night then China and
"2344 UTC N7ET/DU7 28.014 CW 599 Philippines
2340 UTC BV1EL 28.010 CW 599 Taiwan
2311 UTC VK3NX 28.015 CW 599 Australia
1900 UTC ZS3Y 28.373 SSB 55 South Africa"
K5JRN reports on 6 meters from Austin, Texas:
"Interesting conditions observed here on April 4 and 6. On 6 meters
on 4/4/22, I worked HK3X (FJ24) in Columbia and HC1MD/2 (EI97) in
Ecuador while running 30 watts to an indoor dipole wrapped around a
couple of bamboo tomato stakes glued end to end. [I will assume FT8
was the mode. - K7RA]
"That same combo helped me snag HC2DR (FI07) in Ecuador today (4/6).
My signals were not strong, ranging from -13 to -24 in Colombia and
Ecuador. I've also been heard in Argentina and have copied several
Argentinian hams, including LU9AEA (GF05), but have not yet worked
an LU on 6.
"Today, I've also been heard in Uruguay by CX7CO (GF15) but have not
heard any CX stations yet. Indeed, I'm not receiving anyone else on
6 meters except a few locals and those South American stations. The
north-south paths seem like narrow pipelines."
Speaking of "narrow pipelines," I often see this on 10 and 12 meters
using FT8. Monitoring pskreporter.info, on April 7 at 1630 UTC on 12
meters my signal was only reported by stations on the East Coast
over a narrow band, all from 2296-2359 miles from me, at first only
by many stations in Virginia and North Carolina, but not South
Later at 1645 UTC coverage expanded to Florida and Georgia, but
still within that narrow mileage limit. Later by 1720 UTC reports
had spread to New York, Georgia and Florida, and the mileage range
expanded slightly to 2119-2489 miles. But there was one major
exception, HK3A in Bogota, Colombia at 4091 miles.
The night before (local time) at 0220 UTC on 17 meters I was copied
only into a specific area about 2300 miles away in Ohio, Virginia,
Pennsylvania, and Maryland, then suddenly at 0232 UTC the coverage
expanded to California, Oregon, Texas, Alabama, and Florida. All of
this with low power and a crude end-fed indoor antenna, fed with an
UnUn and autotuner.
Thanks to KA7F for the following:
Information on Solar Cycle 25 increasing:
And more from the Southgate Amateur Radio Club:
More solar phenomena:
"On Saturday April 2, 2022 N0LL (EM09) copied LU5VV, CE2SV, LU1WFU
and PV8DX on 50.313 MHz FT8 TEP. I copied CE2SV on TEP and K0SIX
(EN35) calling PY5CC on 50.313 MHz Es at 2109 UTC."
If you would like to make a comment or have a tip for our readers,
For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals. For
an explanation of numbers used in this bulletin, see
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 March 31 through April 6, 2022 were 84, 109,
118, 129, 86, 75, and 61, with a mean of 94.6. 10.7 cm flux was
149,3, 146.6, 143.3, 140.2, 128, 122.4, and 117, with a mean of
135.3. Estimated planetary A indices were 27, 17, 22, 10, 11, 6, and
8, with a mean of 14.4. Middle latitude A index was 18, 12, 19, 7,
8, 6, and 6, with a mean of 10.9.