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ARRL Propagation Bulletin ARLP041 (2019)

ARLP041 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 41  ARLP041
From Tad Cook, K7RA
Seattle, WA  October 11, 2019
To all radio amateurs 

ARLP041 Propagation de K7RA

No sunspots appeared over the past week, and in the prior week there
were only two days with sunspots, so average daily sunspot number
declined from 3.1 to 0.
Average daily solar flux nudged higher, but just barely, from 67.6
to 67.8.
Geomagnetic indicators were much lower this week, with average daily
planetary A index retreating from 14.4 to 6.3, while the
mid-latitude average went from 11 to 5.3.
Predicted solar flux for the next 45 days is 68.  That's correct, on
every day for the next month and a half, October 11 through November
24 the solar flux is forecast to be 68.  This is in line with recent
Predicted planetary A index is 5 on October 11 and 12, 8 on October
13 and 14, 5 on October 15 to 20, then 12, 5 and 5 on October 21 to
23, then 18, 25, 12, 10 and 8 on October 24 to 28, then 5 on October
29 through November 3, 8 on November 4 and 5, 5 on November 6 to 8,
then 8 on November 9 and 10, 5 on November 11 to 16, then 12, 5 and
5 on November 17 to 19, then 18, 25, 18, 10 and 8 on November 20 to
F. K. Janda, OK1HH, sent this geomagnetic activity forecast for the
period October 11 to November 5, 2019.
"Geomagnetic field will be: 
Quiet on:  October 16 and 17, 29 and 30 
Quiet to unsettled on:  October 15, 18 to 20, 22 and 23, November 1 
Quiet to active on:  October 11 to 14, 27 and 28, 31, November (2 to 5) 
Unsettled to active on:  October 21, 26 
Active to disturbed:  October 24 and 25 
Solar wind will intensify on:  October 11 (-14,) 21 to 26
Parenthesis means lower probability of activity enhancement."
Even more news on huge solar blasts in the past:
Mike Schaffer, KA3JAW of Easton, Pennsylvania reported:
"Yesterday, Friday, October 4th, the same 11 meter band double-hop
Es event (reported last week) repeated itself.
But this time it started later during the day, sometime prior to
4:45 pm and vaporized at 6:10 pm ET.  From 5:14 pm onward, local
(within 10 miles) 11M operators were heard mixing with the Puerto
Rico DX.
The signal strength was fairly-good, at times slow short duration
fading with slight distortion due to multipath propagation.
Other station reports:
a. 5:36pm 2136 UTC WP4O FK68ke 28.075.7 DIGI AB1HL FN42kj LoTW 2717
km Black Prop Unknown

b. 5:42pm 2142 UTC WP4O FK68ke 28.075.7 DIGI W1ZQ FN42fu LoTW 2773
km Black Prop Unknown

c. 5:51pm 2151 UTC W1NT FN42lu 28.025.0 CW HK1MW FK20lt LoTW 3582 km
CW 4 dB 26 WPM CQ
a. WP4O Bayamon, PR - AB1HL Cambridge, MA, 1688 miles 

b. WP4O Bayamon, PR - W1ZQ Amherst, NH, 1723 miles 

c. W1NT Newton, NH - HK1MW Barranquilla, Colombia, 2225 miles
It's back, roughly the same time frame as the October 4 report.
On Wednesday, October 9th the 11 meter band opened with double-hop
Es down to the northern Caribbean Sea, from Cuba over to Puerto
It started at 4:40 pm ET (2040 UTC) and vaporized at 6:04 pm (2204
UTC), twenty-eight minutes prior to local sunset.
Signal strength ranged from Faint (1) to Fair (5)."
Ken, N4SO of Alabama sends us his 17 meter notes:
"18.100 MHZ FT8 mode October 7.  Band opening is near sunrise each
day, with a variety of European stations, including Ukraine and
Oman.  Wales was appearing first today.  At band opening there are
no USA stations or South Americans but they are appearing about two
hours later.
There are very few Maritime Mobile stations on the FT8 mode.
Here is one.  Vladimir,  UW5EJX/MM is on a tanker with photos of his
radio and antennas on  Contact was made at 1846 UTC.
184645 -13  0.3 2649 ~  CQ UW5EJX/MM  ( has the Grid/Location)
Power level is 15 watts with a Half Square antenna.
120630 -15  0.1 1047 ~  CQ DX GW0PLP IO72  Wales 
133430   2  1.5 1713 ~  N4SO OM3SEM 73  (Slovak Rep.) 
135700  -1  0.1 1606 ~  N4SO HB9SPACE RR73  (Switzerland) 
141530  -9  0.4 1551 ~  N4SO EA4HBK RR73 (Spain) 
140730 -17  0.3 1737 ~  CQ E75C JN93 Bosnia-Herzegovina 
143700 -11  0.1 2378 ~  N4SO EB3JT JN01  (Spain)"
Martin McCormick, WB5AGZ wrote:
"I believe there is a way to tell if propagation one is hearing is
Sporadic E or F2.

When Sporadic E occurs, the path goes from the transmitter to a
patch of sky in which the E layer is ionized to form a reflective
surface like a mirror which bounces it back to Earth somewhere else.
It is a simple path and the resulting echo fades up and down in
strength but there is no selective fading to give that
characteristic short wave sound as if somebody was continually
twisting the tone controls.  The signal just gets stronger and
F2 reception is more complex because there is more than 1 F layer. 
Since radio signals are nothing more than a different color of
light, they travel at the speed of light with nulls and nodes that
enhance or nullify the carrier on any given frequency from second to
second.  This is what can briefly make an AM signal sound like
sideband and, if you switch to sideband mode, you may hear a
tinny-sounding restoration of the AM audio because the null of the
carrier only kills the carrier, not the side bands.

The effect is much like sweeping a RF notch filter across an AM
signal because that is what the physics of the multiple reflective
layers which may be many miles apart are doing to the signal."
The latest from 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 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 October 3 through 9, 2019 were 0, 0, 0, 0, 0, 0,
and 0, with a mean of 3.1. 10.7 cm flux was 68.2, 68.1, 67.8, 67.4,
67.7, 67.1, and 68.1, with a mean of 67.6.  Estimated planetary A
indices were 5, 7, 7, 5, 6, 5, and 9, with a mean of 14.4.  Middle
latitude A index was 5, 6, 6, 5, 4, 4, and 7, with a mean of 11.


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