Ken Konechy W6HHC 1

Antenna Modelingsoftware

…teaches you more about antennas…how to design better antennas…how to predict antenna performance …how to “tune” for performance…lets you try “what if….”

Ken Konechy W6HHC 2

“What is Antenna Modeling?”

• it is NOT making tiny models

• it is a computer program to predict and analyze antenna performance

Ken Konechy W6HHC 3

“What is Antenna Modeling SW?”

• Allows you to describe your antenna• Allows you to describe your antenna height• Allows you choose construction materials• Allows you to describe your ground conditions• Allows you to analyze gain• Allows you analyze impedance / SWR• Allows you to predict “band-width”• Allows you to plot directivity & front-to-back

Ken Konechy W6HHC 4

Example of an Antenna Modeling Program

Describing a 10M 2-El Beam

Ken Konechy W6HHC 5

Example of an Antenna Modeling Program

Select Material for a 10M Dipole

Ken Konechy W6HHC 6

Example of an Antenna Modeling Program

Select “ground conditions” for a 10M Dipole

• NO GROUND – “free space conditions”

• PERFECT GROUND – “ The perfect world is simulated”

• SOMMERFELD GROUND – “Choose many real conditions”

• REAL GROUND – “Complex, allows nearby cliffs, hills, etc.”

Ken Konechy W6HHC 7

Example of an Antenna Modeling Program

Select “Sommerfeld ground conditions”

Ken Konechy W6HHC 8

Example of an Antenna Modeling Program

Gain plots for a 6-EL 20M Beam

Ken Konechy W6HHC 9

Example of an Antenna Modeling Program

Predicting SWR for a 10M Dipole at 20ft

Ken Konechy W6HHC 10

Let us Explore a 10M Dipole

Gain plots for 10M Dipole over different groundsHeight = 20 ft

Ken Konechy W6HHC 11

Let us Explore a 10M Dipole

Gain plots for 10M Dipole at different heightsOver Sandy ground

Ken Konechy W6HHC 12

Let us Explore a 10M Dipole

Gain plots for 10M Dipole at 5 degree Elev

10.7 dB of the gain is lost at 5 degrees!!!!!!

Ken Konechy W6HHC 13

Let us Explore a 2-EL 10M Beam

Gain plots for 10M Beam at different heights

Ken Konechy W6HHC 14

Explore Antenna Model for 2M J-Pole

J-Pole with “no pipe” – Gain = 5.77 dB

Ken Konechy W6HHC 15

Antenna Model for 2M J-Pole

Four J-Poles with “6-in pipe” to “25-in-pipe”

Ken Konechy W6HHC 16

Antenna Model for 2M J-Pole

J-Pole with “9.5 ft conductive pipe” – Gain = 4.3 dB(-1.5 dB loss from no pipe)

Ken Konechy W6HHC 17

Antenna Model for 2M J-Pole

• Last month we asked whether the length of support of J-Pole made difference??

• Can it be longer than 6 inches??

• The J-pole model showed that gain decreased when pole was 19 in, 25 in & 9.5ft

• I have not yet tried whether grounding the support pole also has an impact on gain…I will now guess…”yes”

Ken Konechy W6HHC 18

Different Antenna Modeling SW• NEC2 – was designed by Lawrence Livermore Labs

• Win-NEC-Plus – uses NEC2 “core” SW with GUI

- by L. B. Cebik, W4RNL - www.nittany-scientific.com

• EZNEC - uses NEC2 “core” software with GUI

- by Roy Lewallen, W7EL - www.eznec.com

• MINI-NEC – simplified NEC2 to run on slow PCs

- fairly obsolete, inaccurate

Ken Konechy W6HHC 19

ARRL Class on Ant Modeling

• If you want to learn how to use NEC2

• ARRL offers class beginning each month.

• On-line Internet class is 16 weeks long

• 3 hours per week

• On-line tutor for help and grading

• Cost $85

Ken Konechy W6HHC 20

Antenna Modelingsoftware

The End

Any Questions??