Flip Beam Antenna (FBA) Moxon Antenna Optimized for F

Transcription

Genesis – the Birth of Antennas
“Why and How Antenna Ideas are
Conceived, Computer Simulated,
Constructed, and Born Into the Wild
for Field Day”
Presenter
Gene Hinkle, K5PA, Austin, Texas
[email protected]
No
Noneed
needto
totake
takenotes.
notes.This
This
entire
entirepresentation
presentationavailable
available
at
atwww.k5pa.com
www.k5pa.com
Copyright © 2004 Gene Hinkle All Rights Reserved
Dedications
z Dr.
John D. Kraus
» W8JK
» Silent Key, July 18, 2004
z Les
Moxon
» G6XN
» Silent Key, March 11, 2004
Moxon Copyright © 2004 Gene Hinkle All Rights Reserved
Genesis – Birth of Antennas
Why
do it?
What do
you need?
Great Outdoor
Activities
Lots of
FUN
Sling Shot Gear
Special Fishing
Spool
Get the Antenna Up
Portable
Masts
Battery Power
Portable
Topics
Methods
z
z
z
z
Conceptual Ideas
Computer Modeling
Examples
Construction
Field Day Usage z Wide Band Dipole
Moxon Beam
z Flipbeam Array (FBA)
z Phased Dipole Array
z Reel Antenna
z
Idea Evolution Creating
Antenna Solutions
Wide Band Dipole
z Moxon Beam
z Flipbeam Array (FBA)
z
Phased Dipole Array
z Reel Antenna
z
Wide Band Dipole
z Desirable
Features
Multiple HF
Bands
Fast Band
Change
Easy to
Match to
Feedline
High
Efficiency
Simple Design
Wide Band Dipole
z
Conceptual Idea
Basic Dipole is Half Wavelength Long
Great for Fundamental and Odd Harmonics
λ/2
EXAMPLES
3.5 MHz – 10.5 MHz – 24.5 MHz
7 MHz – 21 MHz
C
O
A
X
XMIT
GOALS
50 Ohm Z Match to Transmitter
Easy Operation
Radiation Pattern Not Important
Wide Band Dipole
z
Conceptual Idea
Problems
Wide Band Operations are Difficult to Achieve
Coax Losses at High VSWR
Do Not Make λ/2
Twin
Lead
XMIT
RF COAX
Control Line
FEATURES
Off Resonance Operation
Need Antenna Tuner Unit (ATU)
Keep at Antenna to Reduce Losses
ATU
Wide Band Dipole
z
Construction
4:1
BALUN
Tackle Box ATU
ATU
OUT
IN
Balanced or Unbalance
Output Connections
Wide Band Dipole
z
Construction
RF Coax
Cable
Computer Network
Control Cable with RJ-45’s
Wide Band Dipole
z
Field Day Usage
Center Mast
Wires
Low Loss
Ladder Line
Automatic
Tuner Unit
Moxon Beam
z Desirable
Features
Gain Over
Dipole
Easy to
Match to
Feedline
Good Front- High
to-Back Ratio Efficiency
Simple Design Inexpensive
Small Size
Can Be
Rotated
Moxon Beam
z
Conceptual Idea
Reflector
About 5%
Longer Than
Driven Element
Driven
Element
Basic 2-element
Beam
Take a 2-element
Yagi Beam
And Create New
Antenna
Moxon Beam
z
Conceptual Idea
Reflector
Driven
Element
Moxon Beam
z
Conceptual Idea
Elements Fold Back Towards
One Another
Reflector
About 5%
Longer Than
Driven Element
Driven
Element
Basic 2-element
Beam
Reflector
Driven
Element
Increased Mutual
Coupling.
Increased Current on
Element Ends.
Fold the Ends to
Create Moxon Beam
Moxon Beam
z
Conceptual Idea
Reflector
Driven
Element
Moxon Beam
z
Modeling the Moxon
Reflector
Driven
Element
Moxon Beam
z
Modeling
Reality, Stressed
Moxon Bends Inward
The Reflector [4] Uses Insulated
Wire – Dielectric Loading
Shortens Effective Length
Moxon Beam
z
Modeling
1.5
VSWR with 50 Ohm
Source Impedance
VSWR with 75 Ohm
Source Impedance
Moxon Beam
z
Modeling
Elevation Beam Pattern
Azimuth Beam Pattern
Moxon Beam
z
Construction
Gap Spacer Rod
Moxon Beam
z
Construction
Coax Line BALUN
Unit
Driven Element
Being Screwed to Mast Bracket
Moxon Beam
z
Construction
Insulated
Wire
Reflector Element
Screws to Side Rods
Moxon Beam
z
Field Day Usage
Stressed Moxon
Field Day Tripod Mount
6 Meter Moxon Beam
Flipbeam Array (FBA)
z Desirable
Features
Gain Over
Dipole
Easy to
Match to
Feedline
Good Front- High
to-Back Ratio Efficiency
Simple Design Inexpensive
Small Size
Instant
Rotation
z
Conceptual Idea
z
Conceptual Idea
Length is Longer
Lengths are Equal
Reflector
Driven
Element
Moxon is
Asymmetrical
Reflector
Driven
Element
FBA is
Symmetrical
So, Electrically, Lengthen
The Reflector
But... HOW?
z
Modeling
Maximum
Radiation
Reduced
Radiation
Two Feed Lines
One for Power, The Other For Loading
z
Modeling
Reduced
Radiation
Maximum
Radiation
Then Flip
z
Modeling
AZ-EL Patterns
Main Lobe
Azimuth Pattern
Great
Front-Back
Ratio
Elevation Pattern
VSWR Bandwidth Curves
Less than 2:1 VSWR Possible
z
Construction
Dielectric Constant = 3.5
Epoxy Material Fiber Glass
Thickness Wall Varied
50 Mil
Thickness
100 Mil
Thickness
Modeled Resonance Shift
With Thickness
F
(MHz)
SWR
R
(Ohms)
X
(Ohms)
Diel C
Thick
(MIL)
18.8
1.24
41
3.5
3.5
100
19.3
1.3
38.8
3.15
3.5
50
19.4
1.32
38.6
4.36
3.5
40
19.5
1.33
37.7
2.18
3.5
37
20.1
1.43
36.3
6.5
1
0
Modeled Vs. Real Life
650 KHz
Shift Matches
Real Life
37 Mil
Thickness
z
Test Measurements
BALUN
1:1
» Effect of Fiber
Glass Loading on
Resonance
» Test Dipole
» BALUN for
Balanced Feed Line
Construction Techniques
» Detuning Due to Fiber Glass Materials
» Basic Dipole Element – Baseline
Fo
17.500
17.750
18.000
18.250
18.500
18.750
19.000
19.150
19.250
19.500
19.750
20.000
VSWR
4.3
3.7
3.1
2.6
2.0
1.6
1.2
1.0
1.1
1.4
1.8
2.2
Fiberglass Fishing Poles, Wonderpole, Cut to 11' 6" Length Each Wire
Wire ends
Wire ends
Balun 1:1
Rs
Xs
116
119
52' 8.5" RG-58U Coax
67
93
Z Measurement
44
65
37
46
VSWR Without Fiberglass Pole as Element
35
29
37
17
3.0
44
8
50
4
2.5
55
4
69
12
2.0
69
33
50
47
VSWR
z
1.5
1.0
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
Freq (MHz)
» Fiber Glass Lowers Resonant Frequency
» Must Account for This in Final
Dimensioning
Fo
17.500
17.750
18.000
18.250
18.500
18.750
19.000
19.250
19.500
VSWR
2.0
1.8
1.6
1.3
1.2
1.3
1.5
1.9
2.2
Fiberglass Fishing Poles, Wonderpole, Cut to 11' 6" Length Each Wire
Wire ends
Wire ends
Balun 1:1
Rs
Xs
67
42
52' 8.5" RG-58U Coax
52
34
Z Measurement
44
22
41
11
VSWR With Fiberglass Pole as Element
43
7
52
14
67
20
3.0
88
23
95
44
2.5
VSWR
z
2.0
1.5
1.0
17.0
17.5
18.0
18.5
19.0
19.5
20.0
Freq (MHz)
» Overall Shift is -650KHz, So Make Antenna Shorter!
Resonance Shift Due to Fiberglass Pole
4.0
3.5
3.0
VSWR
z
Wire Only
2.5
Wire in Pole
2.0
1.5
1.0
17.00
18.00
19.00
20.00
Frequency (MHz)
z
Construction Details
Driven Element
Cross Arm
Assembly
Driven Element
Driven Element
Exit at End
Wonderpole™ by Shakespeare
z
Construction
Driven Element
Cross Arm Assembly
Element to Boom Assembly Bracket
Home Depot Home Product
PVC Pipe
Insulator
Mast to Boom Assembly Bracket
DX Engineering Product
z
Construction
Phasing Harness with
Relay Box/Control Line
DPDT Relay with
N.O. Contacts
z
Construction
Driven Element Connection
to Side Wires
Phasing Harness Connection
to Driven Element from Mast
z
Field Day Usage
Completed FBA
Up 22 Feet
Inspection of
RF Relay
z
Evolutions
» Greater Gain & F/B
» Switched Beams
Driven
Element
Reflector
(make look inductive)
Director
(make look capacitive)
z
Evolutions
» Greater Gain & F/B
» Switched Beams
Driven
Element
Director
(make look capacitive)
Reflector
(make look inductive)
Flip
Phased Dipole Array
z Desirable
Features
Gain Over
Dipole
High
Efficiency
Easy to
Match to
Feedline
Simple
Design
Inexpensive
Phased Dipole Array
z
Conceptual Idea
» Start with the Basic Dipole Element
Half Wave Length
Dipole Section
Transmitter
Phased Dipole Array
z
Conceptual Idea
» Add More Dipoles, Fields are Adding Broadside
Half Wave Length
Dipole Section #2
Half Wave Length
Dipole Section #1
Half Wave Length
Dipole Section #3
Transmitter
Phased Dipole Array
z
Conceptual Idea
» Notice Polarity of “Phasing” Between Elements
+
Half Wave Length
Dipole Section #2
-+
Half Wave Length
Dipole Section #1
-+
Half Wave Length
Dipole Section #3
-
Transmitter
Phased Dipole Array
z
Conceptual Idea
» Can’t Just Connect Wire Ends; Phasing Destroyed
+
Half Wave Length
Dipole Section #2
++
Half Wave Length
Dipole Section #1
Must Have 180°
Phase Reversal Here!
--
Half Wave Length
Dipole Section #3
-
Must Have 180°
Transmitter
Phased Dipole Array
z
Conceptual Idea
» Can Add Equivalent of 180° of Wire length; “Phasing Harness”
+
Half Wave Length
Dipole Section #2
Fields Due to
AC Current Cancels;
No Radiation From
Phasing Lines
-+
Half Wave Length
Dipole Section #1
Must Have 180°
-+
Half Wave Length
Dipole Section #3
-
Must Have 180°
Transmitter
Phased Dipole Array
z
Conceptual Idea
» Repositioning of Phasing Line
+
Half Wave Length
Dipole Section #2
-+
Half Wave Length
Dipole Section #1
-+
Half Wave Length
Dipole Section #3
-
Phasing Lines
Can Be At Angles.
Remember, No Radiation
Must Have 180°
Must Have 180°
Transmitter
Phased Dipole Array
z
Conceptual Idea
» Further Repositioning of Phasing Line
+
Half Wave Length
Dipole Section #2
-+
Half Wave Length
Dipole Section #1
-+
Half Wave Length
Dipole Section #3
-
Phasing Lines
Can Be Up Close.
Remember, No Radiation
Must Have 180°
Must Have 180°
Transmitter
Phased Dipole Array
z
Conceptual Idea
» Repositioning of Phasing Line
+
Half Wave Length
Dipole Section #2
-+
Half Wave Length
Dipole Section #1
-+
Half Wave Length
Dipole Section #3
-
Phasing Lines
Can Be Wrapped Around – Like Coax!
Must Have 180°
Must Have 180°
Transmitter
Phased Dipole Array
z
Conceptual Idea
Half Wave Length
Dipole Section
Also
180º Phasing
Section
Half Wave Length
Dipole Sections
Phased Dipole Array
z
Conceptual Idea
» Conversion to Modeling
» Overcoming NEC-2 Cores Limitations
180º Phasing
Section
Half Wave Length
Dipole Section
Electrical
Half Wave Length
300 Ohm Feed Line
180º Phasing
Section
Half Wave Length
Dipole Section
Half Wave Length
Dipole Section
300 Ohm Impedance
RF Source
Phased Dipole Array
z
Modeling
» Horizontal
Component
Phased Dipole Array
z
Modeling
» Vert+Horz
Component
» Skywave
Validity
Phased Dipole Array
z
Modeling
Phased Dipole Array
z
Modeling
» Just Like Our Old Friend the Wide Band Dipole – Use a Tuner
» Phasing Line Has Little Effect Off Frequency
» Approximate Locations of Ham Bands Shown
80 M
40 M
30 M
20 M
17 M
15 M 12 M
10 M
Phased Dipole Arrays
z
Evolutions
» Vertical Applications
– “Sleeve Antenna”
» Better Low Angle Performance
Half Wave Length
Dipole Section
Inside
Electrical
Connection
Center Tube
Does Not Touch
Outer Tubing
Ground Radials
(Cylindrical Tubing)
Quarter Wave
Length Section
Feed Point Z
150 Ohms
Phased Dipole Array
z
Construction
» Reel Makes Storage a Snap
Wire
Ends
Balanced
Feed Line
Reel Antennas
z Desirable
Features
Easy to
Unwind or
Wind
High
Efficiency
Easy to
Match to
Feedline
Simple
Design
Inexpensive
Reel Antennas
z
Conceptual Idea
Antenna Elements
Roll Up Onto
a
Reel for Easy
Storage
Feed Line
Feed Line
Feed Line
Need to
Isolate End
From Coax
Line!
Feed Line
Reel Antennas
z
Modeling
» Elevation Pattern
Reel Antennas
z
Modeling
» VSWR
Reel Antennas
z
Construction
» 3 Methods for
Isolation
Coaxial
RF Choke
Resonant
Coax L-C
Trap
Ferrite Bead RF Choke
Reel Antennas
z
Construction
Active Dipole End
Co
ax
RF
Ch
ok
e
Coax Feed Line
Reel Antennas
Reel Antennas
z
Modeling
» Inductance vs. Length
Coax Coil Inductance Vs. Length
(RG-58 on 1-1/2" PVC Pipe)
16.0
Inductance (uH)
14.0
12.0
10.0
8.0
Coil Only
44 pF to Resonate
at 14.2 MHz
6.0
4.0
2.0
0.0
0.00
2.00
4.00
6.00
8.00
10.00
Length (inches)
Reel Antennas
z
Construction
Coil Only
End 2
End 1
Coax Capacitor
Reel Antennas
z
Construction
Coax Capacitor with Final
Length for Resonance
Dipping to Find
Resonance
Completed Coax
L-C Trap
With Coax
Connectors Installed
Reel Antennas
Stub Length
To Create
Resonance
Reel Antennas
Final Antenna VSWR
Reel Antennas
z
Construction
Coax L-C Trap
Antenna
End
Feed Line
Method of VSWR
Adjustment by
Wrapping Capacitor
Around Antenna End
Reel Antennas
z
Construction
Upper Antenna
16 ft. 6 in.
Effective
Feed Point
30 ft.
Fiberglass
Mast
Lower Antenna
16 ft. 6 in.
50 ohm
Transmitter
Resonant Trap Connection Here
Isolator
Reel Antennas
z
Construction
» Reel Really
Makes It EZ to
Stow
Coax L-C
Trap
Where to go for more into ...
z
Reel Antennas
z
Wide Band Dipoles
z
Phased Arrays
z
Moxon Antennas
» New Dipole Feeder- Tuned Feeder Yet!, A.F. Stahler, AA6AX, 73
Magazine, June 1978
» RFD-1 and RFD-2: Resonant Feed-Line Dipoles, James Taylor, W2OZH,
QST, August 1991
» Five Bands, No Tuner, Bill Wright, G0FAH, QST, June 1995
» Antennas for All Applications, John Kraus and Ronald Marhefka,
McGraw Hill, 2002..
» Collinear Phased Antennas for the HF Bands, Douglas Fouts, KI6QR,
QST, March 1989
» The W5GI Mystery Antenna, John Basilotto, W5GI, CQ Magazine, July
2003.
» An Invisible DX Aerial for 14 MHz, Del Arthur, G0DLN, International
Antenna Collection, RSGB, 2003, pp. 103-105.
» HF Antennas for All Locations, Les Moxon, G6XN, 2nd Edition, Printed
2002.
» Two-Element 40-Meter Switched Beam, Carrol Allen, AA2NN, The
ARRL Antenna Compendium, Vol. 6, 1999, pp. 23-25.
Where to go for more into ...
z
Antenna Modeling & Software
» ARRL Antenna Modeling Course, L.B. Cebik, edited by Dean
Straw, American Radio Relay League, 2002.
» EZNEC or EZNEC+, Version 4.0.0, Roy Lewallen,
www.eznec.com/
» MultiNEC, Version 2.2.1, Dan Maguire, AC6LA,
www.qsl.net/ac6la/multinec.html
z
Antenna Modeling Software, Shareware
» 4NEC2,
http://www.qsl.net/wb6tpu/swindex.html
» MMANA, by JE3HHT (Mininec derivative),
http://www.qsl.net/mmhamsoft/mmana/
Thanks
Thanks for
for Being
Being aa Great
Great
Audience
Audience ...
...
See
See You
You in
in the
the Field
Field
You
You can
can download
download this
this presentation
presentation at
at
www.k5pa.com
www.k5pa.com
Slide
Copyright © 2004 Gene Hinkle All RightsEnd
Reserved
Wide Band Dipole - Show ‘n
Tell
z
z
Remote ATU
Ladder Line
Moxon - Show ‘n Tell
z
6 M Moxon Beam
Pieces
Flipbeam Ant - Show ‘n Tell
z
z
z
z
Antenna Flip
Switch Control
Flip Switch Ant
Relay
Antenna Switch
Dipole Element
Collapsed
z
Phasing Harness
Phased Array - Show ‘n Tell
z
20 M Phased
Dipoles with Reel
Reel Antenna - Show ‘n Tell

Flip Beam Antenna (FBA) Moxon Antenna Optimized for F

Transcription

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