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Introduction to Radiosport: Understanding Propagation

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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. - PowerPoint PPT Presentation
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Introduction to Radiosport: Understanding Propagation Leonard Kay, K1NU
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Page 1: Introduction to Radiosport:  Understanding Propagation

Introduction to Radiosport: Understanding Propagation

Leonard Kay, K1NU

Page 2: Introduction to Radiosport:  Understanding Propagation

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

Page 3: Introduction to Radiosport:  Understanding Propagation

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

Page 4: Introduction to Radiosport:  Understanding Propagation

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

Page 5: Introduction to Radiosport:  Understanding Propagation

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

Page 6: Introduction to Radiosport:  Understanding Propagation

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

Page 7: Introduction to Radiosport:  Understanding Propagation

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

Page 8: Introduction to Radiosport:  Understanding Propagation

Quick review – skywave propagation

Page 9: Introduction to Radiosport:  Understanding Propagation

More to scale...

The signal loses strength on each hop

Lower takeoff angle means fewer hops = stronger signal

Page 10: Introduction to Radiosport:  Understanding Propagation

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

Page 11: Introduction to Radiosport:  Understanding Propagation

Software!

Program Before During

Geoclock (shareware)www.geoclock.com

W6EL Prop (free)www.qsl.net/w6elprop

K1TTT MOFWIN (free)www.k1ttt.net/software.html

HFTA (comes with Antenna Book)ARRL Antenna Book CD

Page 12: Introduction to Radiosport:  Understanding Propagation

Geoclock – world map

Page 13: Introduction to Radiosport:  Understanding Propagation

Geoclock – US Map

Page 14: Introduction to Radiosport:  Understanding Propagation

Geoclock – Great Circle map

Page 15: Introduction to Radiosport:  Understanding Propagation

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)

Page 16: Introduction to Radiosport:  Understanding Propagation

W6EL input

Page 17: Introduction to Radiosport:  Understanding Propagation

W6EL output

Page 18: Introduction to Radiosport:  Understanding Propagation

K1TTT MOFWIN

• Geoclock and W6EL rolled into one• Input screen

Page 19: Introduction to Radiosport:  Understanding Propagation

MOFWIN out – 26.10, 0900Z, SF=150

Page 20: Introduction to Radiosport:  Understanding Propagation

MOFWIN out – 26.10, 2000Z, SF=150

Page 21: Introduction to Radiosport:  Understanding Propagation

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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