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Propagation & Solar Activity

Propagation & Solar Activity. 1st hop. 2nd hop. By 19AT072 Jean-Paul. Agenda:. History of Propagation Service Center <PSC> Propagation Modes The Ionosphere Solar Terrestrial Activity Special Propagation Modes Preparing forecasts ???. 1.<PSC> history:.

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Propagation & Solar Activity

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  1. Propagation &Solar Activity 1st hop 2nd hop By 19AT072 Jean-Paul

  2. Agenda: • History of Propagation Service Center <PSC> • Propagation Modes • The Ionosphere • Solar Terrestrial Activity • Special Propagation Modes • Preparing forecasts • ???

  3. 1.<PSC> history: • Problems getting through QRM and pile ups • Understanding HF propagation would offer an advantage • Studying scientific material (library / internet) • Experiments and detailed logging of daily conditions • The need to share information (19AT’s 11-news) • Daily e-mails to WWDX mailinglist

  4. 1.<PSC> history: • Build a website for personal use only, with all kind of indexes on one page. • Upgrading by providing extended forecasts and propagation alerts. • 1998: official launch of the WWDX <PSC> website • Upgrade with a study center (WWDX College) • Other priorities • <PSC> went asleep • 2007: <PSC> revived

  5. 2. Propagation Modes: • Groundwaves: • Can travel only at fixed distances • Max. distance depends on antenna height • Geological influences • Horizontal polarization is favourable

  6. 2. Propagation Modes: • Tropospheric waves: • Travel across the first 10km of the atmosphere • Quiet weather causes sharp differences between air layers in humidity and/or temperature • These temperature or humidity differences are called “inversions” • Inversions can bend radiowaves, especially VHF and higher • On 11m can increase distances up to 250km and more

  7. 2. Propagation Modes: • Ionospheric waves: • Travel between the upper (80-500km) part of the atmosphere and the Earth’s surface • Ionized layers of air bend radiowaves back to Earth • Ionization mainly depends on X-ray and UV radiation from the sun (sunlight) • Ionospheric radiowaves are bent up to 50MHz, and in some occasions beyond 70MHz • On 11m can increase distances up to 20000km and more

  8. 3. The Ionosphere: • D-layer: • Altitude between 50km and 80km • Only absorbs radiowaves (most effect on MF and low HF band up to ±7MHz) • Is ionized by X-rays • Peakes at noon (max. absorbtion) • Appears shortly after sunrise, disappears shortly after sunset

  9. 3. The Ionosphere: • E-layer: • Altitude between 90km and 130km • Reflects radiowaves upto ±5MHz • Absorbs radiowaves above ±5MHz • Is ionized by UV-rays • Peakes shortly after noon • Appears during sunrise and disappears during the night

  10. 3. The Ionosphere: • F1-layer: • Altitude between 160km and 250km • Reflects radiowaves upto ±10MHz • Is ionized by UV-rays • Peakes already in late morning throughout the afternoon • Merges with the F2 layer during the night.

  11. 3. The Ionosphere: • F2-layer: • Altitude between 250km and 450km • Reflects radiowaves upto ±70MHz • Is ionized by UV-rays • Peakes in late morning and late afternoon. Reaches close to max. ionization already shortly after sunrise. • Merges with the F1 layer during the night to form the F-layer

  12. 3. The Ionosphere:

  13. 3. The Ionosphere: • Ionization and ions: • The atmosphere at high latitudes consists out of simple atoms like Oxygen, Hydrogen, Nitrogen, etc. • Atom consists out of neutrons, protons and electrons • X-rays and UV-rays make the electrons break free from their orbit around the core (protons + neutrons) • Electrons become ions which are electrically charged • These energized ions bend radiowaves • More ions, the higher frequency radiowaves is reflected • The denser the air, the faster ions recombine into atoms

  14. 4. Solar Terrestrial Activity: • Sunspots: • Cold areas on the sun’s surface comparable with Earth’s volcanoes. It’s eruptions are called Solar Flares • Produced by strong magnetic forces on the sun’s surface • Sunspots produce much X-ray and UV radiation • Randomly appear, but maximum peaks in 11-year cycle • Appear as “regions” of activity • Radiation causing ionization is measured in Solar Flux index (from 64 up to 250 during a maximum) at 2800MHz

  15. 4. Solar Terrestrial Activity: • Sunspot classification: • Identified by SEC (NOAA Space Environtment Center) as they appear, with a region number. • Regions not numbered yet by SEC, but spotted by <PSC> are numbered with P-number. • Classified by it’s magnetic forces from Alpha (weak) , Beta and Gamma to Delta (very strong) • Classified by the type of sunspots with three lettercode, for example AAX or DSO.

  16. 4. Solar Terrestrial Activity: • Solar Flares: • Produce high levels of radiation (X-ray and UV) • Ejections of large masses of charged particles called Coronal Mass Ejection (CME) • The more magnetically complex the sunspot region, the larger the solar flares it can produce • Measured in the level of X-rays ranging from A, B, C, M to X, for example C3.2 (small) or X8.5 (very large) • A large flare can cause ionoziation to increase shortly

  17. 4. Solar Terrestrial Activity: • The Geomagnetic Field (GMF): • Earth’s rotating iron core produces a magnetic field • Magnetic field diverts constant streams of charged particles from the sun, called the Solarwind • Strong at the equator, weak at the poles • Magnetic pole not at same location as geographic pole • Quiet GMF allows high ionization grades • The status of the GMF is measured with the K-index (3 hourly) ranging from 0 (inactive) to 9 (extreme severe storm). The daily status is measured with the A-index.

  18. 4. Solar Terrestrial Activity: • The Geomagnetic Poles and Geomagnetic Equator:

  19. 4. Solar Terrestrial Activity: • CME: • Cloud of highly charged particles • Travels from the Sun to Earth in 12 to 72 hours. • Partial Halo (partially Earth directed) and Full Halo (fully Earth directed). • Presses down the GMF as Solar Wind speed increases • Black out of HF propagation as GMF becomes unstable • Divertion of particles onto the polar areas where GMF is weak (Aurora appears, as charged particles bombard the atmosphere). K-index can go up from 5 to 9

  20. 4. Solar Terrestrial Activity: • CME hitting Earth:

  21. 4. Solar Terrestrial Activity: • Coronal Hole: • The Corona is the Sun’s atmosphere • A hole in the Corona means charged particles can find their way out speeding up Solar Wind • As Solar Wind speed increases, GMF is pressed down • Possible black out of HF propagation as GMF becomes unstable (K-index can reach upto 5-6) • Divertion of particles onto the polar areas where GMF is weak (Aurora) • Not as strong as CME

  22. Solar Terrestrial Activity: • Cycles and Seasons: • The number of sunspots reaches a maximum every ± 11 years. This is called the Sunspot Cycle • So every ±11 years there is also a minimum • D-layer and E-layer strength are highest during summer (max. absorbtion) • F-layer strength is highest during winter • Sun rotates around it’s axis in 27 days, adding a 27-day cycle

  23. 4. Solar Terrestrial Activity: • Sun’s 27-day cycle:

  24. Current position in Cycle # 24:

  25. 5. Special Propagation Modes: • Es (Sporadic-E): • Ionospheric propagation via Es-layer at 80-130km altitude • Distances from 500-1800km “single hop” • Produces relative strong signals • MUF can reach up to 150MHz and more • Peaks during spring/summer and mid-winter • Appears randomly but peaks late morning and late afternoon

  26. 5. Special Propagation Modes: • TEP (Trans Equatorial Propagation): • Ionospheric propagation via highly ionized and high altitude part of the F-layer • Double reflection in the ionosphere • Works only passing the magnetic equator • MUF can reach up to 400MHz and more • Peaks late afternoon well into the evening

  27. TEP (Trans Equatorial Propagation)

  28. 5. Special Propagation Modes: • Aurora: • Ionospheric propagation via highly ionized and vertically orientated clouds • Clouds work like cracked “mirrors” • Only appears on higher latitudes • Caused by geomagnetic storms (CME etc.) • MUF can reach up to 400MHz and more • Signals very QSB • Sometimes visible at night

  29. Aurora Station A QTH: Amsterdam Station B QTH: Hamburg

  30. 5. Special Propagation Modes: • Backscatter: • Ionospheric propagation via F2-layer • Signal is scattered back when it reflects of the F2-layer or Earth’s surface ???? • Allow to work into the “blind zone” • “Early morning beacon” • “Hollow” modulation like someone is talking into a large pipe or barrel • Directional antenna and some Tx power needed

  31. 6. Preparing forecasts: • How: • Continuously monitor solar activity • Continuously monitor propagation worldwide (make use of clusters) • Make links between changes in solar activity and their effects on propagation • Join the PSC team as an Observer, and become one of the Researchers or Forecasters

  32. 6. Preparing forecasts: • Sources of information: • SOHO website • DXLC website (large archive) • SEC website

  33. 6. Preparing forecasts: • SOHO spacecraft images:

  34. 6. Preparing forecasts: • SOHO EIT (extreme UV) images: Bright areas are active regions. The brighter and larger the area, the more activity.

  35. 6. Preparing forecasts: • SOHO MDI Magnetogram images: Displays the magnetic forces within active regions. The more dense and larger these black/white areas, the stronger the magnetic forces, unleashing solar activity.

  36. 6. Preparing forecasts: • SOHO Lasco C2 images: Displays the Sun’s Corona (atmosphere). Activity on the sun’s limbs and backside can be seen, as well as solar flares and CME’s. Observe the flames shooting out.

  37. 6. Preparing forecasts: • SEC Space Environment Center: X-ray level. Peaks are caused by Solar Flares. High X-ray levels (> C5) causes high absorption in D-layer. If X-ray level rises, usually Solar Flux rises along.

  38. 6. Preparing forecasts: • SEC Space Environment Center: K-index. 3-Hourly geomagnetic index. High indexes (>5) mean stormy conditions, which is bad for the ionosphere.

  39. 7. <PSC> moving forward: • How: • Make <PSC>’s services more accessible • Cooperate with an independent organisation • Expand the team worting on observations, research and forecasts. • Make it a worldwide thing • <PSC> proudly presents the new <PSC>

  40. Thank you !!! • - Better forecasts - • - Better info - • - More accessible - - For everyone - - Independent from any club - - By proud DX’ers for proud DX’ers -

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