Register Account

Login Help

ARRL Propagation Bulletin ARLP010 (2019)

ARLP010 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 10  ARLP010
From Tad Cook, K7RA
Seattle, WA  March 8, 2019
To all radio amateurs 

ARLP010 Propagation de K7RA

After no sunspots over the entire month of February, sunspot group
2734 appeared on March 5. So far the new sunspot numbers are 14, 17,
and 14 on March 5-7. I believe this was the longest consecutive
period (33 days) with no sunspots on this declining side of Cycle
24. The polarity of the new sunspot group identifies it as being
from Cycle 24, not the upcoming Cycle 25.

Frank Donovan, W3LPL sent a link from the Royal Observatory in
Belgium showing brief sunspot appearances on February 13 and 21:

But numbers from NOAA do not show these:

It is interesting to note that we are currently seeing the lowest
sunspot activity since August 2008 during the last solar cycle
minimum, between Cycles 23 and 24.

Frank also sent this link, concerning spotless days:

And a newsletter:

Average daily sunspot numbers for the week increased from 0 to 4.4,
compared to the previous seven days. Average daily solar flux was
unchanged at 70.6

Average daily planetary A index rose from 4.9 to 12.6, and average
mid-latitude A index increased from 4 to 9.7. These geomagnetic
indicators were higher due to effects of a solar wind stream on
February 28 and March 1.

Predicted solar flux is 71 on March 8-12, and 70 on March 13 through
April 21.

Predicted planetary A index is 12, 10 and 8 on March 8-10, 5 on
March 11-13, 10 on March 14-15, 5 on March 16-25, then 12, 30, 28,
14, 8 and 10 on March 26-31, then 8, 5, 10, 15, 12, 12 and 8 on
April 1-7, then 5 on April 8-15, 10 on April 16, and 5 on April

In reference to the predicted planetary A index, here is the
geomagnetic activity forecast for the period March 8 until April 6,
2019 from F.K. Janda, OK1HH.

"Geomagnetic field will be:
Quiet on March 14-15, 23-24
Quiet to unsettled on March 9, 17-18, 22, 25
Quiet to active on March 8, 10-13, 19-21, 31, April 1-2
Unsettled to active on March 16, 26, 29-30
Active to disturbed on March 27-28

"Solar wind will intensify on March (8-9,) 13-14, (15,) 21-22,
25-28, April 1, (2, 5)

"Parenthesis means lower probability of activity enhancement."

Dr. Tamitha Skov, WX6SWW sent this video and report:

"Dear Tad,

"We have been enjoying an unusual increase in activity over the past
week. First, the Sun launched a solar storm that grazed Earth. Nice
to see our solar minimum Sun can still launch storms every now and
again! This solar storm enhanced a relatively weak period of fast
solar wind and caused aurora to drop down to mid-latitudes, lasting
for nearly two days. We haven't seen a storm that engaging since

"As if that wasn't enough fun, two new hot spots have emerged in
Earth view alongside a third bright region that was already visible.
Three active regions on the Earth-facing Sun? We haven't seen that
since 2017!

"Additionally, the biggest and brightest of these hotspots has now
grown into a 'rogue' sunspot. This means it clearly shows an
influence from the coming Solar Cycle 25! Although we cannot
officially designate this region, numbered 2734, as a sunspot from
the new cycle, its magnetic signature is very peculiar. Its magnetic
poles sit one on top of the other instead of side by side. This is
unusual and point to the region being a bit confused as to which
cycle it belongs. I will be sure to report on it in more detail
during my Solar Storm forecast that I'll finish late this week.

"As for the current forecast, expect solar flux to remain in the low
to mid 70s due to the new active regions. This will give radio
propagation a nice boost on Earth's day side. Also, as the solar
storm continues to wane, GPS reception should continue to improve on
Earth's night side and at high latitudes. However, satellite
operators and users should be aware of an increase in anomalies over
the next few days due to the enhanced near-Earth radiation
environment right now. This is especially true for those satellites
in geosynchronous orbits (GEO) like Direct TV and SIRIUS-XM Radio.
So, if your satellite radio glitches while you're listening to your
favorite song, you'll know why.

"Cheers, Tamitha."

In last week's Propagation Forecast Bulletin ARLP009 - - I expressed my confusion over the numbers
in FT8 reports. Thanks to N6KW, N5UWY and others for clearing this
up.  Here is N6KW's missive:

"The FT8 QSO, left to right, is Zulu time, signal/noise ratio in dB,
time deviation in seconds, audio frequency in the passband.

"So JA4FKX's signal was 13 dB below the noise at the time of copy."

N5UWY wrote:

"That's a cut/paste from WSJT-X (K1JT's software package for all the
modes he and his colleagues have developed). Fields are 'UTC, signal
strength in dB relative to the noise level in a 2500-Hz bandwidth,
delta in seconds between received station's clock and UTC, the
number of Hertz above the dial frequency, then the message from the
other station' Japan (or 'JA') is tacked on after the message by the
software to indicate the DXCC entity by name or prefix.

"'343' here means that JA4FKX was transmitting on 10136.343 kHz.
Further, his clock was 0.3 s off UTC (according to the receiving
station's clock which could be off itself!) and the JA's signal was
13 dB DOWN from the noise level that the software was seeing at the

"I am totally an expert now on FT8. I started using it on January 28
and by February 27 or so, I had WAS on 30 m and FT8! Made about 350
QSOs. Got some DX, too. 30 meters is an interesting band and I'm
glad I stuck it out there as I'd never really operated on the band
before. I'm kidding - I am in no way an expert. I didn't even stay
at a Holiday Inn.

"FT8 is kind of addicting but it's fun. Even got an ATNO on 30 -
Reunion Island my 2nd best DX ever. I think I'm running about 50 W
to a trap dipole at about 25-30."

On March 7 NN4X wrote:

"FT8 is a fantastic tool for monitoring prop. It allowed me to
document a fascinating but short 30 minute opening to Africa from
Florida, resulting in RF being expended from my side, but no QSOs.
My antenna: JK Antennas JK-WARC 121730 (3 elements on 17M) at 113

"17M 2019-Mar-07
EA9AK 1502Z
5X2S  1516Z
Z81D  1530Z"

On March 6, Steve wrote:

"Due to dreadful conditions, I seriously did not want to suffer
through the ARRL DX contest last week, but did want to play on the
radio. I've only been on 12M since December 2018, so have been
making a point to check it frequently.

"Just to show that there is propagation, here's a selection of what
I've worked from Florida recently:

"VK3BDX February 28
March 2, 3
CE0YHO March 3, 
T31EU March 2, 3

"So, the moral of the story is, 'Never Give Up Hope.'"

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 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 February 28 through March 6, 2019 were 0, 0, 0,
0, 0, 14, and 17, with a mean of 4.4. 10.7 cm flux was 70.1, 69.9,
69.4, 69.5, 70.9, 72, and 72.5, with a mean of 70.6. Estimated
planetary A indices were 26, 24, 12, 6, 7, 5, and 8, with a mean of
12.6. Estimated mid-latitude A indices were 17, 18, 9, 6, 7, 4, and
7, with a mean of 9.7.


Instragram     Facebook     Twitter     YouTube     LinkedIn