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Antenna Modeling - Getting Started! -
Ward Silver, NØAX ARRL Contributing Editor
You, too, can be an
Antenna Modeling GURU…
5/24/2013 Antenna Modeling - Getting Started 2
in TWENTY minutes!!
5/24/2013 Antenna Modeling - Getting Started 3
You, too, can be an
Antenna Modeling GURU…
5/24/2013 Antenna Modeling - Getting Started 3
in TWENTY minutes!!
Why Do I Want to Do This?
• Learn a LOT about basic antennas
• Antenna know-how is important!
• Antennas that make the most of your lot
• Avoid antennas unlikely to work
• Evaluate antenna sales pitches
• Optimize portable and Field Day antennas
• Opens the door to more tools
5/24/2013 Antenna Modeling - Getting Started 4
Where Do I Start?
5/24/2013 Antenna Modeling - Getting Started 5
5/24/2013 Antenna Modeling - Getting Started 6
But Seriously...
5/24/2013 Antenna Modeling - Getting Started 7
Where Do I Start?
• Which programs?
– EZNEC or 4nec2 are the most popular
– Start with the best basic features, get fancy later
– Try both with a basic model to see which you like
• Add more references
– Antenna Book, Antenna Experimenters Guide (G3LDO)
– L.B. Cebik W4RNL’s website on antennex.com
– Tutorials by Cebik and Ordy W8WWV online
5/24/2013 Antenna Modeling - Getting Started 8
Where Do I Start?
• Read the manual
• Browse the Help files
• Take the whole tutorial
• Join the user’s group or reflectors
• Use articles and books as learning aids
• Modify models and experiment!
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Know Your Terms
• Different types of patterns
• Pattern measurements
• Wavelength-frequency relationship
• Impedance-resonance-reactance
• SWR, basic transmission line terms
• Ground, types of ground, free space
• Know your decibels: dB vs dBm vs dBV vs dBw
5/24/2013 Antenna Modeling - Getting Started 10
Practice the Familiar
• Start with “known-good” models
• Familiar antennas (dipoles, verticals, loops)
• Study beam basics (Yagis and phased arrays)
• Reproduce validated results
• Small changes in design should result in small changes in performance
• Add small features to “known-good” models
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Design
Model
Build
Compare
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Design
Model Compare
Build
There! You’re started!
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Learn the Warning Signals
• Weird patterns or values
• Big changes from small changes
• Warnings from the program
• Double-check
– Use alternative views
– Look at the numbers
• Remember that it’s JUST A MODEL
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“I don’t think anyone has made an EZNEC-to-EZNEC QSO yet!”
Larry W7IUV
THANK YOU!!
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