I developed this presentation for a talk to our local radio club in 2014. It graphically shows how the sun and it's activity affects ham radio activity.The 11 year cycle is explored along with the terms used to describe sunspot activity and it's relationship to radio communication.

1. Our Sun: Good guy or bad guy? 
Radio PropagationRadio Propagation
101101

2. As it turns out, the sun is a
mixture of both for Amateur
radio.
Lets talk about the sun first!

3. NASA Solar imagesNASA Solar images
on Jan 23 – 2012on Jan 23 – 2012
Cycle 24 due to peakCycle 24 due to peak
early 2013. There isearly 2013. There is
plenty of dailyplenty of daily
sunspot activity atsunspot activity at
presentpresent

4. SunspotsSunspots
Sunspots are temporary dark spots that
appear on the surface of the Sun.
Sunspot temperatures are at 3000–4500 K
(2727–4227 °C),while the surrounding sun
activity is at about 5,780 K.
Being colder sunspots appear darker.
Isolated, they would be brighter than an
electric arc.
Sunspots expand and contract as they move
across the surface of the Sun and can be as
large as 80,000 Km (50,000 mi) in diameter,
making the larger ones visible from Earth
without the aid of a telescope.

5. SSN &SSN & SFISFI – They are not the same– They are not the same
Sun Spot Number
Increased sunspot numbers indicate increasing
iononizing radiation of our ionosphere. They vary from
zero to over 200 during the peak of the 11 year cycle.
Solar Flux Index
This is a measurement taken of radio signals taken
from the sun at 2800 Mhz (10.7 Cm)
Solar Flux values range from 60 (No sunspots) to 300

6. Sunspot Groups

7. What the Solar Flare Numbers mean

8. Magnetic & X-Ray Sun RadiationMagnetic & X-Ray Sun Radiation

9. Geomagnetic
Storms can be
your Friend!

10. What is the “A” Index and “K” Index?What is the “A” Index and “K” Index?
““A” IndexA” Index
““K” Index?K” Index?
The A Index describes
the Geomagnetic
conditions for the past
24 hours.
The K Index describes
the Geomagnetic
conditions for the past 3
hours.

11. How do weHow do we
know what theknow what the
sunspotsunspot
activity isactivity is
doing daily?doing daily?
TheseThese
updatedupdated
charts are oncharts are on
must amateurmust amateur
radio websitesradio websites
Realtime Sunspot ChartsRealtime Sunspot Charts

12. The Indexes can change rapidlyThe Indexes can change rapidly

13. Geomagnetic Storm Warning
Its coming at you!!!

14. Where are we heading?Where are we heading?
Sunspots were rarely observed during the Maunder Minimum in the second part of the
17th century (approximately from 1645 to 1715). This coincides with part of a period of
cooling known as the Little Ice Age.
Sunspots quickly rise and more slowly fall on an irregular cycle of 11 years, For
example, from 1900 to the 1960s the solar maximum trend has been upward. From the
1960s to the present is slowly edging downwards.

15. Sunspot Cycles – Every 11 Years
Sunspot Cycles are Notoriously Difficult to Accurately
Predict.
Solar physicists believe that the speed of a massive circulating current of hot plasma within the Sun
predicts the amplitudes of sunspot cycles approximately twenty years into the future. In the years prior to
2006 that speed had become lower than ever before observed.
The National Center for Atmospheric Research predicted Cycle 24 would be intense. NASA predicted
Cycle 25 will be extraordinarily weak. The NCAR prediction for Cycle 24 is shown above in pink. NASA's
Cycle 24 and 25 predictions are shown in red.
Bugger!
The Boffins got
it wrong!!!!

16. Cycle 24Cycle 24

17. Pathetic Cycle 24 on it’s way to 2020Pathetic Cycle 24 on it’s way to 2020

18. How Does the Sun Affect our Ionosphere?How Does the Sun Affect our Ionosphere?

19. Ionospheric D LayerIonospheric D Layer

20. Ionospheric E LayerIonospheric E Layer

21. Ionospheric F LayersIonospheric F Layers

22. Layer HeightsLayer Heights

23. Ionized Ionospheric LayersIonized Ionospheric Layers

24. It is all VERY confusing!It is all VERY confusing!
How does Radio Propagation work forHow does Radio Propagation work for
us during the day and during the night?us during the day and during the night?
Answer: Very well indeed!Answer: Very well indeed!
It all depends on the Sunspot activityIt all depends on the Sunspot activity
and the time of day or nightand the time of day or night
This is how it works ….........This is how it works ….........

25. Know How the Layers Work and You will Work
DX

26. Angle of Radiation -Verticals Rule?Angle of Radiation -Verticals Rule?

27. Angle of radiation is not just a theory…Angle of radiation is not just a theory…
It’s real – if you want to work DXIt’s real – if you want to work DX
High angle of radiation – Little or no reflection andHigh angle of radiation – Little or no reflection and no DXno DX
Low angle of radiation – Good reflection and you workLow angle of radiation – Good reflection and you work DX!DX!

28. Propagation Terms 1Propagation Terms 1
Ground Wave
Are signals that travel on the surface of the earth for short
distances
Skywave
Are signals that reflect off the Ionosphere layers. It is the primary
mode of long distance communication.
Absorption
The D and E layers absorb signals below 4 Mhz during the day
Critical Frequency
The highest frequency at which reflections are returned to earth
from a vertical incidence

29. Propagation Terms 2Propagation Terms 2
Sporadic E Skip
When the E layer becomes highly charged permitting reflection of signals up
to 200 Mhz for a few minutes to a few hours
Tropospheric Ducting
Where waves get trapped between layers and goes long distances. Usually
happens over water. Wonderful news for 6M addicts!
Wave Angle
The angle at which radio waves leave the earth and reflect off the Ionosphere
and back to earth. The angle determines the skip distance
Fading
Fading happens when signals return to earth by two or more separate paths
and cancel each other out. Aircraft, Mountains and ionospheric layers may
also reflect part of a signal while the other part of the signal takes a more
direct path

30. Propagation Terms 3Propagation Terms 3
MUF (Maximum Useable Frequency)
The MUF varies with solar activity and time of day and is the
highest frequency that will reflect off the Ionosphere. If the frequency
used is too high, it will pass through the layers
and disappear into space. e.g The 24Mhz – 28Mhz example
Ionization
The ionization level of the ionosphere reaches it’s minimum just before sunrise
The Grayline
That hour at Sunrise and at Sunset when the DX magic happens!

31. The Grey line is RealThe Grey line is Real

32. How the Grey line worksHow the Grey line works

33. SV3AQR Beacon on 28,123 Mhz. Note the 10Db increase at the beacon's dusk
Not every band, location or terminator path behaves the same way.
Signal strengths along the Grey LineSignal strengths along the Grey Line

34. Understanding Radio Propagation is a bit like
A blind man in a dark cellar searching for
a black cat that isn't there.
It's a highly nebulous process!
That damned cat is
here somewhere!

35. Software that will help you work the rare ones
W6EL Propagation Prediction program: It’s
free and will tell you when there may be a
path opening to where you want your signals
to go.
DX Atlas: This program will tell you everything
about the actually path of your signal. Better
still, it will tell you the exact time you will have
to work “The Gray Line”
Aids ( No, not those aids! )Aids ( No, not those aids! )