Radio Wave Propagation A Refresher Briefing By: Ron, KØMAJ

1. Radio Wave PropagationA Refresher Briefing By: Ron, KØMAJ

3. Introduction • I’m not a genius and I don’t know everything, • I’m just the guy who was selected to make a presentation • I’ve tried to minimize the technical theory and focus on: • Practical concepts • Some info not presented in textbooks • Tips • Techniques • Because of limited time, the focus is on HF

4. The good news: Conditions haven’t been better in 8 years! http://www.smeter.net/propagation/sunspots/current-sunspot-cycle.php

5. Not so good news…

7. Example of actual current propagation Today on 10 Meters: England station , 100 W, 20-foot beam, S-9 +10 (S-3 on dipole)

9. Propagation • “Propagation” refers to the travel of radio • waves from point A to B • A grasp of propagation theory allows you to be a more • professional amateur • If your radio signal does propagate, • who’s out there to receive it?

10. Propagation: If you have it, who’s there to hear you?

11. SEMO ARC Demographics • Extra = 20 • Advanced = 6 • General = 15 • Technician = 12 • Cape = 22 • Jax = 20 • Scott = 4 • Other = 8

12. (Wikipedia)

13. If you aren’t much interested in HF, you might not be • Interested in this topic • Technicians: HF Phone on 28.3 – 28.5 (worldwide) • Many clubs have their own stations • If we had a club HF station, who would be interested?

18. Propagation • Terminology: • HF = 3.0 – 30 MHz (80 -10 meters) • VHF = 30 - 300 MHz • UHF = 300 MHz - 3 GHz • Propagation varies with many factors, including • time of year, time of day, geographical location, • solar and geomagnetic activity, weather, power, • frequency, and antenna type

20. Propagation • Radio waves belong to a family of electromagnetic radiation • Family includes infrared, visible light, ultraviolet, others • Radio waves, like light waves and all • other forms of electromagnetic radiation, • normally travel in straight directions and in all directions away from the source

21. Radio waves weaken as they travel, from the • dispersal of radio energy from its source • Range = distance a radio signal can be received • Mostpropagation at VHF and higher frequency • is usually line-of-sight, so earth curvature and obstacles • are range-limiting factors • HF can travel along Earth surface, “ground waves”

23. The ionosphere (30-260 miles high) is made • up mostly of O2 and N2 • Solar energy, in the form of ultraviolet light (UV) and • X-rays going thru atmosphere can convert gas atoms to • ionosphere layers of ions which can refract radio waves • The ionization plays basic role in long-distance • contacts in amateur bands from 1.8 MHz to 30 MHz • Maximum one-hop skip is about 2500 miles. Beyond • that involves multiple bounces off the ionosphere • VHF and higher usually pass thru ionosphere to space • D-layer: (lowest region) can absorb HF radio waves, • especially 1.8 – 4.0 MHz during day

24. (DX net example including Louri)

25. E-layer: occasionally patches of the E-layer can • become overly ionized and refract even VHF and UHF, • called “sporadic-E” propagation • F-layers: (highest region) refracts HF, divided • into two sub-groups • HF refracted back to earth = “sky wave” or “skip” • Highest frequency that can be refracted = MUF • Lowest frequency that can be refracted = LUF • “Band open” means sky waves are possible

26. Gray line (twilight) • Radio wave-absorbing D-layer disappears faster than the higher • altitude radio wave propagating F2-layer

27. WWV

29. Band Plans (ARRL) (Beacons) • QRP stations with CW ID • If you need CW help, get a CW program from • SEMOARC.net links

30. Audio splitter to your computer

32. DX Cluster NY - Corsica

33. Contests

34. DX Nets • If you can get through to the state-side moderator, • you’ll have a good chance with the DX… • 1100Z : 14.2385 MHz every day • 1430Z : 14.244 • 2000Z : 14.247 • Or, call CQDX yourself

35. ARRL Propagation Charts (solar flux 146) MHz MUF Line LUF Line Zulu

36. Keep in mind that the earth is round when pointing a directional • antenna (central Russia is north of here) • Some times long path works best, due to the ionosphere situation • between two stations, especially if short path >

38. 3 2 1

39. Free HRD Bandscope Various propagation programs available: Google: “radio propagation software”

40. Time Out • I’m out of time (and ideas) • You can view or download this presentation from • the “Links” section of SEMOARC.NET (viewer) • Questions / Comments / Discussions? Japan New York Alaska Iowa Hawaii

41. Radio Wave PropagationA Refresher Briefing By: Ron, KØMAJ

44. Conclusion CQ