1. Introduction to Radiosport: Understanding Propagation
Leonard Kay, K1NU

2. 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

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

4. 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

5. 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

6. 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

7. 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

8. Quick review – skywave propagation

9. More to scale...
The signal loses strength on each hop Lower takeoff angle means fewer hops = stronger signal

10. Signal Arrival Angles and Your AntennasDX
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

11. Software! Program  Before During Geoclock (shareware) 
W6EL Prop (free)
K1TTT MOFWIN (free)
HFTA (comes with Antenna Book)
ARRL Antenna Book CD

12. Geoclock – world map

13. Geoclock – US Map

14. Geoclock – Great Circle map

15. 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)

16. W6EL input

17. W6EL output

18. K1TTT MOFWIN
Geoclock and W6EL rolled into one
Input screen

19. MOFWIN out – 26.10, 0900Z, SF=150

20. MOFWIN out – 26.10, 2000Z, SF=150

21. What does it all mean? Strategy Antennas
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