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Introduction to Radiosport: Understanding Propagation

Introduction to Radiosport: Understanding Propagation. Leonard Kay, K1NU. A (very) Short Course in HF Propagation for Contesters. Propagation: What’s important Why do we care? What data do we need, and how do we get it? How do we use it? Tools to help you.

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Introduction to Radiosport: Understanding Propagation

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  1. Introduction to Radiosport: Understanding Propagation Leonard Kay, K1NU

  2. A (very) Short Course in HF Propagation for Contesters • Propagation: What’s important • Why do we care? • What data do we need, and how do we get it? • How do we use it? • Tools to help you

  3. Sample: MOFWIN map – 26 October, 2000Z, SF=150

  4. Propagation: Why do we care? • Bottom line: We want to: • Maximize rate (primary, strong paths) • Maximize multipliers (weaker primary and secondary paths) • Have fun (maybe work some new band-countries!) • Propagation conditions determine band openings • What band(s) • When • To where • Quality of openings (signal strength, arrival angles) • All stations being equal, we win by exploiting more openings • Important for both SO and MO

  5. Propagation:Where does the data come from? • Predictive Software • Based on empirical and theoretical models • Inputs • time & date • QTH • solar parameters(flux/SSN, A index, K index) • frequencies • Output • path openings as function of time and freq • Empirical • experience and Conventional Wisdom • HFTA - arrival angle files

  6. Propagation: How do we use it? • Operating strategy • Know your band openings • ‘General’ openings for your QTH • EU: morning – high bands • Specific details per time of year, contest (DX/local), and solar cycle • 15m to EU: open at 1000Z or 1300Z? • Plan your operating time accordingly • Optimize your antennas • Best use of takeoff angle

  7. The Sun • 11-year sunspot cycle • 27-day rotation period • Daily parameters • Solar flux, A index, K index • From WWV [SH/WWV on packet] • web site

  8. Quick review – skywave propagation

  9. More to scale... The signal loses strength on each hopLower takeoff angle means fewer hops = stronger signal

  10. Signal Arrival Angles and Your Antennas • DX • Typically low: 0° – 30° • Need high yagis (at least /2,  pref.)or verticals (gain a plus) • Local • Typically higher: 20° - 90° • Lower dipoles or other horiz-polarized antennas • An antenna can be too high

  11. Software!

  12. Geoclock – world map

  13. Geoclock – US Map

  14. Geoclock – Great Circle map

  15. W6EL Prop • Windows version of DOS MINIPROP • Models D, E, and F layers • Text based • Other useful utilities • Great circle map • Frequency map (similar to MOFWIN)

  16. W6EL input

  17. W6EL output

  18. K1TTT MOFWIN • Geoclock and W6EL rolled into one • Input screen

  19. MOFWIN out – 26.10, 0900Z, SF=150

  20. MOFWIN out – 26.10, 2000Z, SF=150

  21. What does it all mean? • Strategy • Know your band openings and plan around them • Primary paths for rate • Hunt for multipliers on other paths • Use software before and during the contest • Fine-tune your strategy and identify openings • Real-time monitors • Antennas • DX: • Get your yagis as high as possible • Put up verticals • Local: • Low dipoles and other high-angle radiators

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