Exploring antennas
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Exploring Antennas. Van Warren AE5CC. Exploring Antennas: Pattern. D esign S imulate M easure R efine. Exploring Antennas: Rule 1. Don’t reinvent the wheel. Explore and understand successful designs before inventing new ones. Exploring Antennas: 2m.

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Exploring Antennas

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Exploring antennas

Exploring Antennas

Van Warren

AE5CC


Exploring antennas pattern

Exploring Antennas: Pattern

D esign

S imulate

M easure

R efine


Exploring antennas rule 1

Exploring Antennas: Rule 1

Don’t reinvent the wheel.

Explore and understand successful designs before inventing new ones.


Exploring antennas 2m

Exploring Antennas: 2m

Single Most Important Parameter:

Wavelength

Middle of band is 146 MHz

Middle of CW band is 144.05 MHz


Exploring antennas 2m1

Exploring Antennas: 2m

Middle of band is 146 MHz

146 MHz = 2.053 meters = 6.7 feet = 80.83 inches

Full Wavelength


Exploring antennas 2m2

Exploring Antennas: 2m

General Purpose 2m Antenna in free space.


Exploring antennas 2m3

Exploring Antennas: 2m

General Purpose 2m Antenna with Ground Plane (-5 Hz shift)


Exploring antennas 2m4

Exploring Antennas: 2m

General Purpose Ground Plane Antenna.


Exploring antennas 2m5

Exploring Antennas: 2m

General Purpose Antenna at 144 MHz In Free Space


Exploring antennas 2m6

Exploring Antennas: 2m

General Purpose Antenna with Ground Plane at 144 MHz


Exploring antennas 2m7

Exploring Antennas: 2m

Same Antenna at 900 MHz (33 cm band).


Exploring antennas loops

Exploring Antennas: Loops

Now duplicate argument using tetrahedral geometry reasoning from the simplex argument and minimal materials and tesselation of sphere for balloon borne 2m antenna. Also reduce to ¼ wave and compare gain with full wavelength cases.


Exploring antennas loops1

Exploring Antennas: Loops

Design Antenna

Simulate Antenna

Measure Antenna

Improve


Design antenna requirements

Design Antenna: Requirements

Use 42 AWG

DX: 1 – 1000 MHz

TX: 80 – 2m 50 watts

Aesthetic, preferably invisible

Low Lightning Hazard

Low Structural Hazard

Easily Relocated

Inexpensive


Design first pass wire loop

Design First Pass: Wire Loop

0.0025 in diameter

Materials 42 AWG 

DX: 1 – 1000 MHz

TX: 80 – 2m

Aesthetic, preferably invisible 

Low Lightning Hazard 

Low Structural Hazard 

Easily Relocated 

Inexpensive 


Design pass vary parameters

Design Pass: Vary Parameters

- Start: 42 AWG - 0.00125” radius

Observe Effects of:

Wire Diameter Variation

Frequency Variation

Loop Geometry Variation

add recursive elements

in plane/out of plane elements

- 160, 80, 40, 20, 10, 6, 2, 0.7, 0.3 meters

- 1.9, 3.5, 7, 14, 28, 50, 144, 420, 902 MHz


Exploring antennas

“Large” Circular loop has relatively

flat frequency response,

but surprisingly, high directionality!

(front/side ratio)

This borders on discovery!

Compare with microphone gain patterns

and yagi’s or “beam” antennas.

Total gain @ 20 MHz

Results suggest a wire loop

Can be “aimed” by simply

Changing the feed point.

Suggests a new radar antenna.

Stationary loop, moving feed point.

What is radiative efficiency?


Exploring antennas

Need a program that will let me preprogram a series of mouse positions, clicks and key presses, to create animations of the gain patterns of these loop antennas.

These are necessary and wonderful animations.


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