Propagation and Solar
Issues
Carl Luetzelschwab K9LA
k9la@arrl.net
http://k9la.us
TCDXA Oct 2014 K9LA
TCDXA Oct 2014 K9LA
What We’ll Cover





Update on Cycle 24
Another Maunder Minimum?
Hints for Working FT4TA Tromelin
What Do the Numbers Mean?
What Bands Are Good? When Are
They Good?
TCDXA Oct 2014 K9LA
Cycle 24 Update

Cycle 24 in terms of 10. 7 cm solar flux
180
latest monthly
September 2014
10.7 cm Solar Flux
160
latest smoothed
March 2014
140

120
100

80
60
Jan
Jul
2009
Jan
Jul
2010
Jan
Jul
2011
Jan
Jul
Jan
2012
Jul
2013
Jan
Jul
2014
Jan
Jul
Jan
2015
K9LA - Mar 2014


Cycle 24
began in
late 2008
First peak
after 3½
years
Second
peak after
about 6
years –
still in
progress
We’re still in the second peak
Higher bands should be good this fall/winter
TCDXA Oct 2014 K9LA
Cycle 24 vs Cycle 23
smoothed 10.7 cm sf
Cycle 23
Cycle 24
200.0
180.0
160.0
140.0
120.0
100.0
80.0
60.0
0
12
24
36
48
60
72
84
96
108 120 132 144 156
months after minimum
Will Cycle 24 have a similar
long descent to minimum?
TCDXA Oct 2014 K9LA
Speaking of Minimums . . .
smoothed sunspot number
22
between Cycles 18 and 19
(min Apr 1954)
20
18
16
between Cycles 19 and 20
(min Nov 1964)
14
12
between Cycles 20 and 21
(min Jun 1976)
10
8
between Cycles 21 and 22
(min Sep 1986)
6
between Cycles 22 and 23
(min Oct 1996)
4
2
between Cycles 23 and 24
(min Dec 2008)
0
1
6
11
16
21
26
31
36
41
46
51
56
number of months below a smoothed sunspot
number of 20


We were used to short minimums – about 2 years
Then the minimum between Cycle 23 and 24 came
along
TCDXA Oct 2014 K9LA
250
200
150
Next Solar Max vs Duration of Previous Solar Min
100
50
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
solar cycle number
100
80
250
R2 = 0.5815
200
150
100
50
0
10
60
20
30
40
50
60
70
80
90
100
months at solar minimum (smoothed sunspot number < 20)
40
20
0
1-2
2-3
3-4
4-5
5-6
6-7
7-8
8-9
9-10
10-11
11-12
12-13
13-14
14-15
15-16
16-17
17-18
18-19
19-20
20-21
21-22
22-23
23-24
num ber of m onths below a
s m oothed s uns pot num ber of
20
120
maximum smoothed
sunspot number of next
solar cycle
maximum smoothed sunspot
number
Length of Min vs Next Max
sola r m inim um be tw e e n indic a te d c yc le s
The longer the minimum,
the smaller the next cycle
TCDXA Oct 2014 K9LA
maximum smoothed sunspot
number
Recorded History
250
200
150
100
50
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
solar cycle number



Three periods of larger cycles
Two periods of smaller cycles
It looks like we’re headed for a period of smaller
cycles
TCDXA Oct 2014 K9LA
How Small?
Another Maunder Minimum?
Cycle 1


Maunder min was a 70-year period of
very few sunspots
1645-1715
TCDXA Oct 2014 K9LA
MM Fueled By Mag Field Data




July 2009 paper by W.
Livingston and M. Penn
Sunspots are visible when
their magnetic field
strength is > 1500 gauss
Extrapolating the linear
trend line says no sunspots
will be visible by the end of
the decade (2020)
Is this the signature of a
Maunder Minimum?
TCDXA Oct 2014 K9LA
Update Thru 2013


Magnetic field strength still decreasing
But it looks like it is starting to level off
TCDXA Oct 2014 K9LA
Update Thru September 2014


It sure looks like it’s leveled off
Suggests sunspots won’t disappear
TCDXA Oct 2014 K9LA
MM Conclusion – For Now!



It’s kind of looking like we’ll just see
an extended period of smaller cycles
Not a period of few or no sunspots
We’re going into uncharted territory
• The Sun will do whatever it wants!
TCDXA Oct 2014 K9LA
FT4TA Tromelin

End of October thru early November
2014
• mid point is ~ Nov 5



They plan to concentrate on the
higher-volume bands 
Second priority is the low bands 
Let’s look at propagation from the
MSP area to Tromelin
TCDXA Oct 2014 K9LA
Great Circle Paths from FT4TA
MSP
FT4TA
antipode
FT4TA
great circle paths in 10o increments
TCDXA Oct 2014 K9LA
W6ELProp Map

Pretty close to
a high latitude
path
• More sensitive
to elevated K
and A indices


TCDXA Oct 2014 K9LA
Short path
(red) heading
to the NE
Long path
(black)
heading to the
SW
Predictions on the Higher Bands

Black line is
monthly median
MUF
• 50% of the days
of the 1-month
period centered
on Nov 5

Blue line is
monthly median
FOT
• 90% of the days

short path



White = S8
Yellow = S7
Green = S6
Red = S5
20m – good opportunity from 2200-0300 UTC
17m, 15m, 12m – good opportunity from 1400-2200 UTC
10m – 50% probability from 1600-1900 UTC
TCDXA Oct 2014 K9LA
Predictions on the Higher Bands





long path

Long path
openings are
pretty much
limited to
around and
after sunrise
White = S5
Yellow = S4
Green = S3
Red = S2
Best shots are
• 20m: 13-15z
• 17m: 14-16z
• 15m: 14-16z
TCDXA Oct 2014 K9LA
FT4TA on 160-Meters


Know when the entire path is in darkness
(referred to as common darkness)
For stations in the MSP area
• MSP sunset is around 2253 UTC
• FT4TA sunrise is around 0148 UTC
• Approximately 3 hours of common darkness

Watch especially around FT4TA sunrise
• Up to a half hour before and a bit after

All this also applies to 80-Meters, and to
40-Meters to a lesser extent
TCDXA Oct 2014 K9LA
Wedge of Daylight
The terminator
at FT4TA
sunrise
superimposed
on the
terminator at
FT4TA sunset
All of NA should be able to work FT4TA on
160-Meters (if someone is on at each end!)
TCDXA Oct 2014 K9LA
Headings to FT5ZM on 160m
FT5ZM
black lines are
great circle
paths out of
FT5ZM

FT5ZM – 77 reports from topband operators
• 49 true great circle paths, 28 other paths
For FT4TA, start with short path,
but always check other directions
TCDXA Oct 2014 K9LA
What Do the Numbers Mean?
image from www.qrz.com
• SFI is 10.7 cm solar flux
• Generally the higher the flux, the better the higher bands
• But the short-term correlation between daily SFI and daily
MUF is poor
• SN is sunspot number
• Ditto above comments
TCDXA Oct 2014 K9LA
Numbers - continued
• K is 3-hr index
• Tells how disturbed the Earth’s magnetic field is
• Generally an elevated K index gives lower mid and high
latitude MUFs
• An elevated K index may enhance low latitude MUFs
• 0-9, with 0 = quiet and 9 = extremely disturbed
• A is daily average of the eight 3-hour K indices
• 0-400, with 0= quiet and 400 = extremely disturbed
TCDXA Oct 2014 K9LA
Numbers - continued
• XRY is x-ray flux at 1-8 Angstroms (0.1-0.8 nm)
• B, C, M, X - B is least, X is most
• Higher letters indicate more adverse impact to D region
• 304A is flux from Sun at 304 Angstroms (30.4 nm)
• 26-34 nm ionizes greater than 50% of F2 region
• See SFI and SN comments
• Aur is auroral activity from NOAA satellite
• Roughly correlates to K index
• Lat is lowest geographic latitude impacted by auroral event
TCDXA Oct 2014 K9LA
Numbers - continued
• Bz is direction of interplanetary magnetic field (IMF)
• +50 to -50, negative indicates south with disturbed conditions
• SW is solar wind speed in km/s
• Average is around 400 km/s
• Much higher values suggest CME or coronal hole
• PF is proton flux at geosynchronous altitude
• Values of 10 and higher suggest polar cap absorption (PCA)
• EF is electron flux at geosynchronous altitude
• Values less than 10 suggest disturbed magnetic field
TCDXA Oct 2014 K9LA
Numbers - continued
• MUF Bdr is the MUF over the Boulder ionosonde at the designated
time assuming it’s the mid point of a 3000 km path
• EME deg is estimated Earth-Moon-Earth path attenuation in words
• Band prognosis
• Caveat emptor – subjective assessment
• Geomag Field is assessment of K index in words
• Sig Noise Lvl is estimated noise in S-units due to SW and K
• Could be masked by man-made and atmospheric noise
• CME (UTC) is estimated time when coronal mass ejection will hit
TCDXA Oct 2014 K9LA
What Bands? When?

160m, 80m, 40m are driven by absorption
• These bands are best during night at solar min

15m, 12m, 10m are driven by MUF
• These bands are best in daylight at solar max

30m, 20m, 17m are good throughout an
entire solar cycle
• Can withstand more absorption than
160/80/40m
• Don’t need as high a MUF as 15/12/10m
TCDXA Oct 2014 K9LA
What Bands? When?

Right now during 2nd peak of Cycle 24
• 15m, 12m and 10m are best
• 30m, 20m and 17m are good
• 160m, 80m and 40m generally not considered good


But you can still work lots of DX around solar max
Fall/winter of 2015/2016
• 15m, 12m and 10m openings will decrease
• 30m, 20m and 17m will be the best bands
• 160m, 80m and 40m better

Fall 2016 and onward
• 15m, 12m and 10m will be mostly noise
• 30m, 20m and 17m will still be good
• 160m, 80m and 40m will also be good
TCDXA Oct 2014 K9LA
Summary

We’re in the second peak of Cycle 24
• It won’t last forever
• Take advantage of good propagation on the higher
bands now!

Recent data suggests that we’re not headed into
another Maunder Minimum
• Just a period of small solar cycles
• Dust off the low band gear


FT4TA should be very workable on all bands
We are inundated with space weather data
• I think it’s too much – but it’s colorful!

In the next several years we’ll transition from the
higher bands being best to the lower bands being
best
TCDXA Oct 2014 K9LA