Transcript "Family Tree of Antennas" - David Conn VE3KL

Family Tree of Antennas
David Conn VE3KL
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Acknowledgements
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Doug Leach VE3XK
Bert Barry
VE3QAA
QCWA Members
The Inventors
References given in
slides
ARRL Antenna book
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Why Make a Family Tree
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To understand the overall (complex) picture
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To enable us to select a good antenna
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To organize and compare existing designs
Antenna Types
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Antenna Types 1…6
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Resonant Wires: Dipole, Yagi, Quad, Vertical,
Moxon Square …….
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Long wires (non-resonant): Zepp/G5RV…
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Resistively Loaded: Beverage, Pennant,
Rhombic …
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Small Loops/Wires: Resonant Loading Circuits
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Antenna Types 1…6
5. Phased Arrays: Yagi, Collinear, Sterba Curtain,
Rhombic, Four Element Rectangular Array,
Many Others …
6. Lens Antennas for UHF/Microwaves: Parabolic
Dish, Helix …
Family Tree
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Transmission Lines
Radiation
Waves
Circuits
Transmitting Antennas
Receiving Antennas
SNR
Amateur Radio
Antennas
(index)
Simulation/Smith Chart
MF
Ground/Ionosphere
Power
Microwave
HF
UHF/VHF
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Transmitting Antennas
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Performance measured by Gain & Directivity
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Low Loss: Transmitter Matching
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SWR of 2:1 loses half the power
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Ground/Ionosphere… dominates
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Polarization (Vertical for MF Transmitters)
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Receiving Antennas…SNR
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Performance measured by RDF (dB)
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RDF (Receiving Directivity Factor) defined
as peak response in desired direction to
average response in all directions
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Ground/Ionosphere… extremely important
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Consider Polarization: VHF weak signal (DX)
uses Horizontal Polarization
Antenna Examples
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MF Antennas
Need good S/N…not Gain for Receive
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Inverted L, T
Beverage Antenna… the best?
Terminated loops (Pennant, Flag)
Vertical Phased Arrays
Vertical GP antennas
K9AY Loop
4 Square Vertical
Green indicates Receive Only Antenna
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Inverted L,T,Vertical,K9AY Antennas
http://www.antennex.com/preview/archive3/ltv.htm
http://www.aytechnologies.com/TechData/LoopInstall.htm
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MF Receiving Antenna Performance
RDF, dB
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Vertical phased array B/S
2 Broadside Beverages 1.75 W
Good
Beverage 1.0 W
8.64
Small 4X4 Square
Flag/Pennant
Dipole
K9AY
Vertical Omni
Beverage 0.5 W
5.0
80 m high
Bad
Cost
Low Dipole
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http://www.w8ji.com/antennas.htm
Classic Dipole: type 1 .. Elevation Plot
35 feet
Ground
RDF = 8.3 dB Good
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Classic Dipole: type 1 .. Azimuth Plot
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Classic Vertical Ground Plane: type 1
RDF =5 dB
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Two Element Quad…Azimuth: type 1
RDF = 12.84 dB…high
31 feet high
to top
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End Fed Zepp Antenna: type 2
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MF Pennant…Receive only: type 3
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Ground independent
Very Low Gain (-35 dB)
RDF = 7.39 dB…OK
Cardoid pattern
F/B 25 dB
Small..20 feet each arm
Terminated loop class
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Small Magnetic Loop Antenna: type 4
Very High Voltages
g3ycc.karoo.
net/loop.htm
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Microwave Antenna Array: type 5 & 6
Space Diversity
Transmitter
Receivers
Wanted Rays
Unwanted Rays
Arrays
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Arrays
► Driven
arrays: Collinear, Sterba and Bobtail
Curtains, two dimensional arrays, three
dimensional (lens) arrays, Log Periodic
 End fire or broadside or any beam shape
► Parasitic
arrays: Yagi
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Linear Arrays (Driven)
Directivity increases with Length
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Four Element Rectangle.. Easy to
Visualize
ARRL Antenna
Book
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Collinear Arrays
http://www.tpub.com/neets/book10/42i.htm
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Bobtail Curtain Driven Array
Maximum Gain 4.5 dBi
Low Angle Radiation
ARRL Antenna Book
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Log Periodic Antenna Array…looks like a tapered Yagi
but each element is driven
► Very
Broad Band
► Dimensions repeat
logarithmically
► QST Sept. 2002
ARRL Antenna Book
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VHF/UHF/Microwave Antennas
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Yagi, Quagi, Quads ….stacked versions
Cycloid Dipole…
Circular Polarization..Repeaters
Helix and Helix Arrays
Vertical, Jpole
Corner Reflectors, Parabolas, Lenses
Circuit board patch antenna arrays
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The J Pole Antenna: type 1
Easy to Build
• No ground plane
needed
• Many designs
available
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http://www.cebik.com/jp2.html
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Cycloid Dipole
Circular Polarization…Repeaters: type 1
http://www.wa7x.com/cycloid_info.html
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Summary
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Tree must include antenna design as well as the
physical description
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Tree must include: ground effects, basics of the
ionosphere
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Tree must link to the most important well proven
designs
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Tree must help amateurs at all levels to select an
appropriate antenna
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Many Thanks: Especially to the
Organizers
http://www.dxlc.com/solar/
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