Transcript Cycle 24 Update - Carl Luetzelschwab K9LA

Cycle 24 Status – and Much More
Carl Luetzelschwab K9LA
[email protected]
PVRC Webinar 18 & 21July 2012
K9LA
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Topics
• Quick review of August 2009 presentation
• Recent data
– Solar min review
– Cycle 24 status
– Cycle 24 looking ahead
• Seasonal effects on propagation
• Four relevant Cycle 24 questions
• Two other topics
– Effect of trees
– Best height for an antenna
PVRC Webinar 18 & 21July 2012
K9LA
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Quick review of August 2009 presentation
PVRC Webinar 18 & 21July 2012
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smoothed sunspot number
August 2009 Webinar
22
20
18
16
14
12
10
8
6
4
2
0
between Cycles 18 and 19
(Apr 1954)
between Cycles 19 and 20
(Nov 1964)
between Cycles 20 and 21
(Jun 1976)
between Cycles 21 and 22
(Sep 1986)
between Cycles 22 and 23
(Oct 1996)
between Cycles 23 and 24
0
5
10
15
20
25
30
35
40
months from descent below smoothed
sunspot number of 20
We were at solar min – how long would it last?
PVRC Webinar 18 & 21July 2012
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August 2009 Webinar
From Dr. David
Hathaway (MSFC, 2009)
• We’d been seeing Cycle 24 sunspots for about a year and a half
• But Cycle 24 hadn’t started ramping up yet
PVRC Webinar 18 & 21July 2012
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August 2009 Webinar
• Prior to this July 2009
prediction, ISES had
been carrying two
predictions
• One for a “high”
cycle (140)
• One for a “low”
cycle (90)
• Long duration solar
minimum led to
decision to go with
“low” cycle prediction
International Space Environment Service
PVRC Webinar 18 & 21July 2012
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Most recent data
PVRC Webinar 18 & 21July 2012
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Recent Solar 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
months from descent below a smoothed
sunspot number of 20
Longest of our lifetimes
PVRC Webinar 18 & 21July 2012
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All Solar Minimums
Average duration ~ 37 months
100
80
60
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
sola r m inim um be tw e e n indic a te d c yc le s
We’ve had similar minimums – even longer minimums
(assuming our data is good back then)
PVRC Webinar 18 & 21July 2012
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Next Max vs Previous Solar Min
maximum smoothed
sunspot number of next
solar cycle
Next Solar Max vs Duration of Previous Solar Min
250
R2 = 0.5815
200
150
100
50
0
10
20
30
40
50
60
70
80
90
100
months at solar minimum (smoothed sunspot number < 20)
Looks like we’re headed for a small cycle
PVRC Webinar 18 & 21July 2012
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First Sunspot of Cycle 24
PVRC Webinar 18 & 21July 2012
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Current Cycle 24 Data
100
90
80
Cycle 24 monthly mean
Sunspot Number
70
Cycle 23 monthly mean
60
smoothed
50
40
30
20
10
0
J MM J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N
2006
2007
2008
2009
2010
2011
2012
• Solar min around December 2008
• Cycle 24 slow to start its ascent
• Have we reached Cycle 24’s peak or is this just a temporary lull?
PVRC Webinar 18 & 21July 2012
K9LA
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In Terms of 10.7 cm Solar Flux
Solar Min Between Cycle 23 and 24 and Cycle 24 Ascent
in terms of 10.7 cm solar flux
160
150
monthly mean
140
smoothed
10.7 cm Solar Flux
130
120
110
100
90
80
70
60
J MM J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N J M M J S N
2006
2007
2008
2009
2010
2011
2012
Similar trends
PVRC Webinar 18 & 21July 2012
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Geomagnetic Field Activity
Smoothed Sunspot Number and # of Days in Month With Ap < 7
# days in month with Ap
<7
Jan-12
Jan-10
Jan-08
Jan-06
0
Jan-04
0
Jan-02
6
Jan-00
40
Jan-98
12
Jan-96
80
Jan-94
18
Jan-92
120
Jan-90
24
Jan-88
160
Jan-86
30
Jan-84
200
Jan-82
smoothed sunspot
number
Cycle 21 decline through Cycle 24 Ascent
Month, Year
• Still quieter than 1996 solar minimum – too quiet?
• Where is 160-Meters?
– Are we seeing the effect of galactic cosmic rays?
PVRC Webinar 18 & 21July 2012
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Cycle 24 vs Cycle 23
C y c le 24 v s C y c le 23
C yc le 23
C yc le 24
s moothed s uns pot
number
140
120
100
80
60
40
20
0
0
10
20
30
40
50
60
70
80
90
100
months after s olar minimum
• For a short time Cycle 24 rate of ascent was comparable to Cycle 23
• But Cycle 24 was slower to start – tends to indicate lower cycle
PVRC Webinar 18 & 21July 2012
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Current Predictions
90
60
International Space Environment Service
Marshall Space Flight Center
PVRC Webinar 18 & 21July 2012
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A Very Early Prediction
If only it were true!
PVRC Webinar 18 & 21July 2012
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Seasonal effects
PVRC Webinar 18 & 21July 2012
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Seasonal Effects
• With the smoothed sunspot number hovering
•
around 60 (smoothed 10.7 cm solar flux around
120) beginning in August 2011, seasonal effects
become noticeable for 10m propagation
Let’s look at the MUFs along two paths at a
smoothed sunspot number of 60
– W3 to EU, to JA, and to S. America
– G to Eastern EU, to W4, and to JA
PVRC Webinar 18 & 21July 2012
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W3 to EU
35
30
MHz
25
20
W3 to DL
15
28 MHz
10
5
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
• October thru December good for 10-Meters
• Summer months worst
PVRC Webinar 18 & 21July 2012
K9LA
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W3 to JA
35
30
25
20
W3 to JA
15
28 MHz
10
5
0
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
• October best for 10-Meters
• Summer months worst
PVRC Webinar 18 & 21July 2012
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W3 to S America
35
30
25
20
W3 to LU
15
28 MHz
10
5
0
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
• September thru April good for 10-Meters
– Thanks to the robust equatorial ionosphere
• Summer months worst
PVRC Webinar 18 & 21July 2012
K9LA
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G to Eastern Europe
30
25
MHz
20
G to LZ
15
28 MHz
10
5
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
• October thru February best for 10-Meters
• Summer months worst
PVRC Webinar 18 & 21July 2012
K9LA
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G to W4
35
30
25
20
G to W4
15
28 MHz
10
5
0
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
• October thru February good for 10-Meters
• Summer months worst
PVRC Webinar 18 & 21July 2012
K9LA
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G to JA
35
30
25
20
G to JA
15
28 MHz
10
5
0
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
• October best for 10-Meters
• Summer months worst
PVRC Webinar 18 & 21July 2012
K9LA
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Last Fall vs This Spring
• Decrease in monthly mean solar activity resulted
•
•
in leveling off of the smoothed value
As we moved from Fall/Winter to the Spring,
seasonal effects came into play
In general, 10-Meters for CQ WW and ARRL 10M
good, ARRL DX and CQ WPX not so good
• This Fall – 10-Meters should be good
• But we need a more active Sun to help with 10Meter propagation next Spring!
PVRC Webinar 18 & 21July 2012
K9LA
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Four FAQs
PVRC Webinar 18 & 21July 2012
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#1 - Two Peaks for Cycle 24?
• Cycle 19, 20, and
•
21 didn’t show
much of a second
peak
Cycle 22 and 23 did
show a definite
second peak
– Cycle 23’s second
peak made 6-Meter
DXers very happy in
the Winter of 2001
Cycle 24 could have a second peak
PVRC Webinar 18 & 21July 2012
K9LA
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#2 - 6-Meter F2?
• Paths not involving the equatorial ionosphere are
•
•
very unlikely with the current Cycle 24 prediction
• TEP is still possible
If F2 does happen away from the equator, it
would be most likely during the Spring, Fall, and
Winter of 2013
Sporadic E should still be there
– Late morning and early evening in the Summer
– Early evening in December
PVRC Webinar 18 & 21July 2012
K9LA
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Recent 6m Opening - W7 to EU
29 June 2012
foF2 ~ 4.7 MHz
F2 MUF ~ 17.4 MHz
foEs > 9.5 MHz
Es MUF > 50 MHz
Probably not F2 – most likely Es
PVRC Webinar 18 & 21July 2012
K9LA
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#3 - Disappearing Sunspots?
• W. Livingston and M. Penn
measured the maximum
strength of magnetic fields
of sunspots
• Strength has been declining
since 1992
• Need about 1500 gauss for
sunspots to be visible
• Extrapolating their data says
sunspots will disappear by
2016
PVRC Webinar 18 & 21July 2012
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extrapolation
31
2012 Update
Slope the same as previous
plot – vertical axis in this
plot is expanded
So what if sunspots disappear?
Remember that sunspots are a proxy for the true ionizing
radiation (EUV), which still appears to be alive and well
PVRC Webinar 18 & 21July 2012
K9LA
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Sunspot Number vs Solar Flux
If sunspots are disappearing, we might expect to
see a decrease in the correlation of smoothed
sunspot number and smoothed 10.7 cm solar flux
Aug us t 1947 throug h D ec ember 2011
Aug us t 1947 throug h D ec ember 1996
(pe a k of C yc le 18 throug h e nd of C yc le 22)
(pe a k of C yc le 18 throug h sta rt of C yc le 24)
300.0
R 2 = 0.9908
s m oothed 10.7 c m s olar
flux
s m oothed 10.7 c m s olar
flux
300.0
250.0
200.0
150.0
100.0
50.0
0.0
R 2 = 0.981
250.0
Cycle 23/24 data
200.0
150.0
100.0
50.0
0.0
0
50
100
150
sm oothe d sunspot num be r
200
250
0
50
100
150
sm oothe d sunspot num be r
200
250
Also impacts propagation predictions using smoothed sunspot number
PVRC Webinar 18 & 21July 2012
K9LA
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#4 - Another Maunder Minimum?
• Maunder Minimum - lack of
•
•
•
•
•
sunspots from 1645-1715
The three cycles before
Maunder Minimum showed a
smooth decrease in group
sunspot number
It’s generally agreed that the Sun is “slowing down”
Cycles 22, 23, and 24 exhibit a smooth decrease, too
What Cycle 24 does and duration of solar min between
Cycle 24 and 25 may suggest where we’re headed
It very well may be there will still be an ionosphere
PVRC Webinar 18 & 21July 2012
K9LA
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Trees and HF propagation
PVRC Webinar 18 & 21July 2012
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Trees and HF
• All of my antennas
look through trees
on headings from
Northwest thru
South
• Is this a problem?
PVRC Webinar 18 & 21July 2012
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Trees and HF – Two Issues
• Foliage (leaves)
– Use the work of Tamir and Krevsky
PVRC Webinar 18 & 21July 2012
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Foliage
• Conductivity
much more
significant than
permittivity
• Mid latitude
woods
– Minor effect at
LF
– More effect as
frequency
increases
• But my trees
PVRC Webinar 18 & 21July 2012
K9LA
are deciduous –
probably very
minor effect in
winter
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Trunk (Chunk of Lossy Dieletric)
• Technical Correspondence, Nov 1991 QST
• 75m vertical in pine trees
• Distances
• High voltage portion too close to trunk
• Try to keep high voltage portion greater than .023
•
wavelengths from trunk
These experiments were with wire parallel to tree trunk
– Beverage antenna probably more forgiving
PVRC Webinar 18 & 21July 2012
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Best antenna height
PVRC Webinar 18 & 21July 2012
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Best Height for Antenna
EU
JA
AF
SE Asia
OC
SA
USA
30
Indianapolis to the
world on 10-Meters
25
percetn of the time
20
15
10
5
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 25 26 27 28 29 30 31
elevation angle, degrees
• Elevation statistics in the ARRL Antenna Book CD from N6BV’s work
• Example: Indianapolis to six areas of the world and to the US
PVRC Webinar 18 & 21July 2012
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Antenna Patterns
5-el a t 25 ft
5-el a t 50 ft
5-el a t 100 ft
20
perc etn of the time or g ain in
dB i
15
10
5
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 25 26 27 28 29 30 31 32
elev atio n an g le, d eg rees
5-element 10m monobander over average ground
PVRC Webinar 18 & 21July 2012
K9LA
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Elevation Statistics + Patterns
all elevation angles
5-el at 25 ft
5-el at 50 ft
5-el at 100 ft
percetn of the time or gain in dBi
20.0
15.0
10.0
5.0
0.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
elevation angle, degrees
• Best “compromise” height is ~ 1.5 wavelengths (50 ft)
– Agrees with W2PV’s analysis in his book Yagi Antenna Design
• Need to stack antennas to cover all the angles
PVRC Webinar 18 & 21July 2012
K9LA
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Summary
• Cycle 24 has leveled off
– Is this temporary or are we at the peak?
– Next several months will give us a clue
• Cycle 24 has a decent chance of two peaks
– Would likely prolong propagation on the higher bands
• 6M F2 propagation probably restricted to equatorial ionosphere
• Sunspots may disappear, but EUV will likely still be there
• Too early to tell if we’re headed for another Maunder Minimum
• Even if we are, maybe it doesn’t matter with respect to propagation
• Expect good 10-Meter contest season for CQ WW and ARRL 10M
• ARRL DX and CQ WPX next spring need more solar activity
• Don’t worry too much about trees – especially in the winter
• Try to put your antenna at the “optimum” height
PVRC Webinar 18 & 21July 2012
K9LA
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