Wave Propagation Presented by Bob Kenyon K 8

Wave Propagation Presented by: Bob Kenyon - K 8 LJ CRES Amateur Radio Club 4/22/2008

Agenda • Introduction and background • Basic propagation concepts • Propagation software overview • Modeling program examples • Demo of W 6 ELProp and Ionoscope • Open discussion & conclusion

Primary Propagation Modes • Ground wave - AM BC band daytime; HF across town • Space wave - Point to point (ground not involved) ~ 30 mi. • Sky wave (the focus of this presentation) - Refraction via the ionosphere - Makes world-wide communications possible • Satellite communications - Artificial propagation (repeater in the sky)

Other Propagation Modes • Back scatter and side scatter • Rain scatter • Tropospheric ducting • Meteor scatter • Gray line (day - night line) • Aurora • Moon bounce

Some Basic Concepts • Wave Reflection - Occurs primarily at earth’s surface • Wave Refraction - Bending that occurs in the ionosphere and elsewhere • Wave Diffraction - Bending over the earth’s surface or around obstacles

Reflection and Refraction =

Diffraction Around and Over an Object (Not to scale) . .

The Earth and Environs (Not to scale) Ionosphere 250 miles 23 miles 6. 5 miles Earth Troposphere Stratosphere* * Isothermal region

Layers of the Ionosphere (Not to scale)

Ole Sol (The Sun) A massive nuclear furnace which produces the following: • Visible light (what we can see) • Ultraviolet light (ionizes the F layer) • Soft X-rays (ionizes the E layer) • Hard X-rays (ionizes the D layer - RF sponge) • Solar wind (charged particles that impact the earth’s magnetic field • Solar flares & coronal mass ejections (CMEs) • Sunspots (increases ionization of the F layer)

The Electromagnetic Spectrum Increasing Wavelength Increasing Frequency Optical Window Radio Window

Solar Flare Ionospheric Effects Sun Electromagnetic Radiation Increase Delay 8. 3 min Solar Cosmic Rays Delay 15 min – Several Hours Ultraviolet And X-Rays High Energy Protons & Particles D-Layer Increase (SWF) D –Layer Increase (PCA) SWF = Short Wave Fading PCA = Polar Cap Absorption Magnetic Storm Particles Delay 20 -40 Hrs Low Energy Protons And Electrons Magnetic Storms Auroras Sporadic E D – Layer Increase (Auroral Absorption)

Some Propagation Terms • Critical Frequency The highest frequency returned to earth when transmitted vertically • Critical Angle The highest angle at a given frequency which will be returned to earth • Maximum Useable Frequency (MUF) The highest frequency returned to earth between two specific points • Skip Zone Area between the ground wave end and 1 st sky wave reception

Frequency vs. Ionospheric Refraction

Frequency vs. Critical Angle

Critical Angle and the Skip Zone

Close-up View of Actual Sunspot Taken by NSO Sacramento Peak Vacuum Tower Telescope

100, 000 Kilometers

More Propagation Terms • Sunspot number (SN) - Weighted average of actual sunspots and groups of sunspots • Smoothed sunspot number (SSN) - SN averaged over + and - 6 months (13 months) • Solar flux - Measurement of solar radio noise at 2800 MHz. (10. 7 cm) • K index (Kp index - planetary) - A mid latitude geomagnetic index updated every 3 hours (scale 0 - 9) • A index (Ap index - planetary) - A daily measure derived from the K index (scale 0 - 400)

Some General Principals • Sunspot impact is a long term phenomenon - Observe months and years, not hours or days • Geomagnetic activity is more short term - Hours or even minutes can be very important • Use the planetary (Kp and Ap indices) A K Conditions 0 2 3 4 7 15 27 48 80 132 208 400 0 1 1 1 2 3 4 5 6 7 8 9 Quiet to unsettled Unsettled Active Minor storm Major storm Severe storm Very major storm

Guide to Propagation Conditions Using Solar Indices

Smoothed Solar Flux vs. Smoothed Sunspot Number (SSN)

Penticton, B. C. 10. 7 cm Solar Flux Monitoring Facility (2800 Mhz)

Smoothed Solar Flux vs. Smoothed Planetary A Index

Last Sunspot Cycle (23)

Comparison of Last Three Solar Cycles (21, 22, & 23)

400 Years of Sunspot Observations Pilgrims Land at Plymouth Rock American Revolution

Solar Cycle 24 Sunspot Number Prediction

Future Sunspot Cycle Predictions

Propagation Software (Sample) Public Domain (Free) • W 6 ELProp V 2. 7 (demo next) • VOACAP Commercial • ASAPS V. 4 $275 • HFx V. 1. 1 $129 • CAPMan $89 • Win. CAP Wizard 2 $29. 95 • Prop. Lab Pro $150

Demonstration of W 6 ELProp V 2. 7 and Ionoscope

Conclusion

References (1) Davies, K. , Ionosopheric Radio, London: Peter Pereginus, 1989. (2) The ARRL Antenna Book, Newington, CT: ARRL, 2002 (3) Jeffrey S. Beasley & Gary M. Miller, Modern Electronic Communication, 9 th Edition, Columbus, OH: Prentice Hall, 2008 (4) Jacobs, G. , Cohen, T. , Rose, R. , The NEW Shortwave Propagation Handbook, CQ Communications, Inc. , Hicksville, NY: 1995 (5) The ARRL Handbook, Newington, CT: ARRL, 2002 (6) Mc. Namera, L. F. , Radio Amateur’s Guide to the Ionosphere, Malabar, FL: Krieger Publishing Co. , 1994