1 / 47

Radio Wave Propagation A Refresher Briefing By: Ron, KØMAJ

Radio Wave Propagation A Refresher Briefing By: Ron, KØMAJ. 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

decima
Download Presentation

Radio Wave Propagation A Refresher Briefing By: Ron, KØMAJ

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


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

  2. 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

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

  4. Not so good news…

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

  6. 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?

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

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

  9. (Wikipedia)

  10. 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?

  11. 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

  12. 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

  13. 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”

  14. 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

  15. (DX net example including Louri)

  16. 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

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

  18. WWV

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

  20. Audio splitter to your computer

  21. DX Cluster NY - Corsica

  22. Contests

  23. 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

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

  25. 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 >

  26. 3 2 1

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

  28. 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

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

  30. Conclusion CQ

More Related