HF Propagation Can we work Winter FD? Ionospheric Layers Making - - PowerPoint PPT Presentation

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HF Propagation Can we work Winter FD? Ionospheric Layers Making - - PowerPoint PPT Presentation

Nov 27, 2023 228 likes •598 views

HF Propagation Can we work Winter FD? Ionospheric Layers Making Ionosphere Sun creates ions Form layers above the earth Fairly predictable Day Night Seasons Sunspots Making Ions Making Ionosphere Layers Ionospheric

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HF Propagation

Can we work Winter FD?

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Ionospheric Layers

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Making Ionosphere

  • Sun creates ions
  • Form layers above the earth
  • Fairly predictable

– Day – Night – Seasons – Sunspots

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Making Ions

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Making Ionosphere Layers

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Ionospheric Layers

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Ionospheric Refraction

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What’s your Fc?

  • The highest frequency that bounces is critical

– Straight up and back down – Fc is the nomenclature

  • Realtime Fc map
  • http://www.spacew.com/www/fof2.html

– Updated every 5 minutes for free – Buy software for >$200

  • Where does it come from?
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Critical Frequency

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Ionograph

  • Profile of Critical Frequency, and MORE
  • Digisonde

– automatically plot a vertical profile

  • Project of Umass, Lowell
  • Stations all over the world
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UMass Lowell

  • University of Massachusetts – Lowell
  • Space Science Lab

– http://ulcar.uml.edu/digisonde.html

  • GIRO

– Global Ionosphere Research Organization

  • IRTAM

– IRI Real-Time Assimilative Mapping

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UML-SSL

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GIRO worldwide sites

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GIRO site Reports

  • http://umlcar.uml.edu/WatchIt/latestIonogram

.html

  • All sites

– http://umlcar.uml.edu/WatchIt/latestIonograms.ht ml

  • Any one site

– https://lgdc.uml.edu/common/DIDBFastStationList

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http://giro.uml.edu/IRTAM/

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LoS and Skip

  • Line of Site

– Distance based on antenna tower height for VHF

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Critical Frequency

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Ionospheric Refraction

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See MUF vs Distance chart

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Montgomery vs Dallas

Pelham Montgomery Dallas

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Wire Antenna Pattern

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Vertical Antenna

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Two Wavelength Horizontal

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V Beam Antenna

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MUF vs LUF

  • I didn’t discuss LUF

– Lowest Usable Frequency – Skywave problem – Daytime problem

  • MF problem – 160M

– Ignore it for night time HF

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URLs

  • https://ns6t.net/azimuth/azimuth.html
  • http://www.cvarc.org/resources/Tech_Articles

/14-MUF-04-R.pdf

  • http://www.spacew.com/www/fof2.html
  • http://ulcar.uml.edu/digisonde.html

– http://umlcar.uml.edu/WatchIt/latestIonograms.html – http://umlcar.uml.edu/WatchIt/latestIonogram.html – https://lgdc.uml.edu/common/DIDBFastStationList – http://giro.uml.edu/IRTAM