Antennas

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Antennas Frank Donovan, W3LPL
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Antenna Secrets of the Top Multi-Op Stations
Revealed !
How do the top multi-op stations break those
huge pileups so fast? How do they consistently
make 5000 to 8000 QSOs in one weekend ? Of
course, they have great operators, full legal
power, great locations, and theyre really
serious competitors... But thats not enough !
Its not even close... They all use stacked
monoband Yagis at carefully chosen heights But
the most competitive multi-ops do much more
The antenna secrets of the Top
Multi-ops... And tips to apply to your own
station!
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Secret 1 Use All of the Right Angles
Do your antennas cover all of these elevation
angles? The top multi-ops cover them all (or
almost all) Europe
Asia/Pacific 80M 10 - 30
deg (100 - 200 ft) 7 - 18 deg (150 -
200 ft) 40M 7 - 23 deg (100 - 200 ft)
5 - 15 deg (120 - 200 ft) 20M 5 - 18 deg
(75 -100 ft) 4 - 12 deg (100 - 200 ft)
15M 4 - 15 deg (60 - 90 ft) 3 -
10 deg (90 - 200 ft) 10M 3 - 12 deg (50 -
80 ft) 2 - 8 deg (80 - 200 ft)
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Secret 1 Use All of the Right Angles
Of course, its extremely difficult to cover all
of the right angles So Tip 1 Design
your antennas for as many of the right angles as
you can. A good compromise is 50 - 100
feet for Europe 80 - 100 feet (plus) for
Asia/Pacific
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Secret 2 Eliminate Radiation Pattern Nulls
Low antennas have clean radiation patterns -
with no nulls - but poor low angle radiation
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5 Element 20 Meter Yagi on 48 Foot Boom, 50 Feet
High
18 degrees
No nulls...
Europe
degrees
50 FT
Poor low angle radiation
5 degrees
decibels
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5 Element 20 Meter Yagi on 48 Foot Boom, 50 Feet
High
No nulls...
12 degrees
degrees
Asia/Pacific
50 FT
Poor low angle radiation
4 degrees
decibels
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Secret 2 Eliminate Radiation Pattern Nulls
High antennas produce excellent low angle
radiation but have deep nulls at very important
elevation angles
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5 Element 20 Meter Yagi on a 48 Foot Boom, 200
Feet High
12 degrees
Europe
degrees
Deep null
Excellent low angle radiation
4 degrees
decibels
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5 Element 20 Meter Yagi on a 48 Foot Boom, 200
Feet High
12 degrees
degrees
Deep null
Asia/Pacific
Excellent low angle radiation
4 degrees
decibels
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6 Element 15 Meter Yagi on a 48 Foot Boom, 200
Feet High
15 degrees
Deep null
degrees
Europe
Deep null
Excellent low angle radiation
4 degrees
decibels
12
6 Element 15 Meter Yagi on a 48 Foot Boom, 200
Feet High
10 degrees
degrees
Deep null
Asia/Pacific
Excellent low angle radiation
3 degrees
decibels
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7 Element 10 Meter Yagi on a 48 Foot Boom, 200
Feet High
12 degrees
degrees
Deep null
Europe
Deep null
Excellent low angle radiation
3 degrees
decibels
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7 Element 10 Meter Yagi on a 48 Foot Boom, 200
Feet High
degrees
8 degrees
Deep null
Asia/Pacific
Excellent low angle radiation
2 degrees
decibels
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Secret 2 Eliminate Radiation Pattern Nulls
Well designed stacked Yagis provide the best of
both! - low angle radiation, and - null-free
radiation patterns Tip 2 Use stacked Yagis
to produce broad null-free patterns that cover
the full range of needed elevation
angles Stacked Yagis require a tower 70 to 100
feet tall
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Two Stacked 5 Element 20 Meter Yagis on 48 Foot
Booms, 50 and 100 Feet High
18 degrees
BOTH
Europe
100
degrees
50 FT
5 degrees
decibels
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Two Stacked 5 Element 20 Meter Yagis on 48 Foot
Booms, 50 and 100 Feet High
BOTH
12 degrees
100
degrees
Asia/Pacific
50 FT
4 degrees
decibels
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Two Stacked 6 Element 15 Meter Yagis on 48 Foot
Booms, 47 and 94 Feet High
15 degrees
BOTH
degrees
Europe
94 FT
47 FT
4 degrees
decibels
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Two Stacked 6 Element 15 Meter Yagis on 48 Foot
Booms, 47 and 94 Feet High
BOTH
10 degrees
degrees
94 FT
Asia/Pacific
47 FT
3 degrees
decibels
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Two Stacked 6 Element 10 Meter Yagis on 36 Foot
Booms, 35 and 70 Feet High
12 degrees
BOTH
degrees
Europe
70 FT
35 FT
3 degrees
decibels
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Two Stacked 6 Element 10 Meter Yagis on 36 Foot
Booms, 35 and 70 Feet High
BOTH
degrees
8 degrees
70 FT
Asia/Pacific
35 FT
2 degrees
decibels
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Two Stacked 3 Element 40 Meter Yagis on 48 Foot
Booms, 100 and 200 Feet High
23 degrees
Europe
BOTH
degrees
200
100 FT
7 degrees
decibels
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Two Stacked 3 Element 40 Meter Yagis on 48 Foot
Booms, 100 and 200 Feet High
16 degrees
BOTH
degrees
Asia/Pacific
200
100 FT
5 degrees
decibels
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Secret 3 Stacks for Europe and Asia are
Different!
Stacked Yagis that produce an optimum null-free
higher angle radiation pattern for Europe cannot
produce the optimum lower angle pattern for
Asia/Pacific Stacked Yagis that produce an
optimum null-free low angle radiation pattern for
Asia/Pacific... cannot produce the optimum higher
angle pattern for Europe
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Secret 3 Stacks for Europe and Asia are
Different!
The solution is Tip 3 Use switchable stacks
of three Yagis to select broad null-free
radiation patterns for either Europe or
Asia/Pacific
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Three Stacked 5 Element 20 Meter Yagis on 48 Foot
Booms 50, 100, 150 Feet High
18 degrees
50 FT/100 FT
Europe
degrees
5 degrees
100 FT/150 FT
decibels
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Three Stacked 5 Element 20 Meter Yagis on 48 Foot
Booms 50, 100, 150 Feet High
50 FT/100 FT
12 degrees
degrees
Asia/Pacific
100 FT/150 FT
4 degrees
decibels
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Three Stacked 6 Element 15 Meter Yagis on 48 Foot
Booms 47, 94 and 140 Feet High
15 degrees
47 FT/94 FT
degrees
Europe
94 FT/140 FT
4 degrees
decibels
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Three Stacked 6 Element 15 Meter Yagis on 48 Foot
Booms 47, 94 and 140 Feet High
47 FT/94 FT
10 degrees
degrees
Asia/Pacific
94 FT/140 FT
3 degrees
decibels
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Three Stacked 6 Element 10 Meter Yagis on 36 Foot
Booms 35, 70 and 105 Feet High
35 FT/70 FT
12 degrees
degrees
Europe
70 FT/105 FT
3 degrees
decibels
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Three Stacked 6 Element 10 Meter Yagis on 36 Foot
Booms 35, 70 and 105 Feet High
35 FT/70 FT
degrees
8 degrees
Asia/Pacific
70 FT/105 FT
2 degrees
decibels
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Antenna Secrets of the Top Multi-Op Stations
Revealed !
Secret 1 Use All of the Right Angles Secret
2 Eliminate Radiation Pattern Nulls Secret 3
Stacks for Europe and Asia are Different!
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Tips to Apply to Your Own Station
Tip 1 Design your antennas for as many of the
right angles as you can. A good compromise
is 50 - 100 feet for Europe 80 - 100
feet (plus) for Asia/Pacific Tip 2 Use
stacked Yagis to produce broad null-free
patterns that cover the full range of needed
elevation angles Stacked Yagis require a tower 70
to 100 feet tall Tip 3 Use switchable stacks
of three Yagis to select broad null-free
radiation patterns for either Europe or
Asia/Pacific