antennas frank donovan, w3lpl. antenna secrets of the top multi-op stations revealed ! how do the...
TRANSCRIPT
Antennas
Frank Donovan, W3LPL
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 they’re really serious competitors...
But that’s 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!
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/Pacific80M 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)
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
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 Yagion 48 Foot Boom, 50 Feet High
decibels
degr
ees
50 FT
5 degrees
Europe
Poor low angleradiation
18 degrees
No nulls...
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5 Element 20 Meter Yagion 48 Foot Boom, 50 Feet High
decibels
degr
ees
50 FT
4 degrees
Asia/Pacific
Poor low angleradiation
12 degrees
No nulls...
Secret #2: Eliminate Radiation Pattern Nulls
High antennas produce excellent low angle radiationbut have deep nulls at very important elevation angles
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5 Element 20 Meter Yagion a 48 Foot Boom, 200 Feet High
decibels
degr
ees
Deep nullEurope
12 degrees
4 degrees
Excellent low angleradiation
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5 Element 20 Meter Yagion a 48 Foot Boom, 200 Feet High
decibels
degr
ees
Deep null
Asia/Pacific
12 degrees
4 degrees
Excellent low angleradiation
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6 Element 15 Meter Yagion a 48 Foot Boom, 200 Feet High
decibels
degr
ees
Deep null
Deep null
Europe
15 degrees
4 degrees
Excellent low angleradiation
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6 Element 15 Meter Yagion a 48 Foot Boom, 200 Feet High
decibels
degr
ees
Deep null Asia/Pacific
10 degrees
3 degrees
Excellent low angleradiation
0
2
4
6
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12
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7 Element 10 Meter Yagion a 48 Foot Boom, 200 Feet High
decibels
degr
ees
Deep null
Deep null
Europe
12 degrees
3 degrees
Excellent low angleradiation
0
2
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7 Element 10 Meter Yagion a 48 Foot Boom, 200 Feet High
decibels
degr
ees
Deep null Asia/Pacific
8 degrees
2 degrees
Excellent low angleradiation
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 patternsthat 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 Yagison 48 Foot Booms, 50 and 100 Feet High
decibels
degr
ees
BOTH
100’
50 FT
Europe
18 degrees
5 degrees
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12 degrees
Two Stacked 5 Element 20 Meter Yagison 48 Foot Booms, 50 and 100 Feet High
decibels
degr
ees
BOTH
100’
50 FT Asia/Pacific
4 degrees
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Two Stacked 6 Element 15 Meter Yagison 48 Foot Booms, 47 and 94 Feet High
decibels
degr
ees BOTH
94 FT
47 FT
Europe
15 degrees
4 degrees
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Two Stacked 6 Element 15 Meter Yagison 48 Foot Booms, 47 and 94 Feet High
decibels
degr
ees BOTH
94 FT
47 FT Asia/Pacific
10 degrees
3 degrees
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Two Stacked 6 Element 10 Meter Yagison 36 Foot Booms, 35 and 70 Feet High
decibels
degr
ees BOTH
70 FT35 FT
Europe
12 degrees
3 degrees
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Two Stacked 6 Element 10 Meter Yagison 36 Foot Booms, 35 and 70 Feet High
decibels
degr
ees BOTH
70 FT35 FT Asia/Pacific
8 degrees
2 degrees
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Two Stacked 3 Element 40 Meter Yagison 48 Foot Booms, 100 and 200 Feet High
decibels
degr
ees BOTH
200’100 FT
Europe
23 degrees
7 degrees
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Two Stacked 3 Element 40 Meter Yagison 48 Foot Booms, 100 and 200 Feet High
decibels
degr
ees BOTH
200’100 FT
16 degrees
5 degrees
Asia/Pacific
Secret #3: Stacks for Europe and Asia are Different!
Stacked Yagis that produce an optimum null-free higher angleradiation pattern for Europe…cannot produce the optimum lower angle pattern for Asia/Pacific
Stacked Yagis that produce an optimum null-free low angleradiation pattern for Asia/Pacific...cannot produce the optimum higher angle pattern for Europe
Secret #3: Stacks for Europe and Asia are Different!
The solution is:
Tip #3: Use switchable stacks of three Yagis to select broadnull-free radiation patterns for either Europe or Asia/Pacific
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Three Stacked 5 Element 20 Meter Yagison 48 Foot Booms; 50, 100, 150 Feet High
decibels
degr
ees
50 FT/100 FT
100 FT/150 FT
Europe
18 degrees
5 degrees
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Three Stacked 5 Element 20 Meter Yagison 48 Foot Booms; 50, 100, 150 Feet High
decibels
degr
ees
50 FT/100 FT
100 FT/150 FT
Asia/Pacific
12 degrees
4 degrees
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Three Stacked 6 Element 15 Meter Yagison 48 Foot Booms; 47, 94 and 140 Feet High
decibels
degr
ees
Europe
15 degrees
4 degrees
47 FT/94 FT
94 FT/140 FT
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Three Stacked 6 Element 15 Meter Yagison 48 Foot Booms; 47, 94 and 140 Feet High
decibels
degr
ees
10 degrees
3 degrees
47 FT/94 FT
94 FT/140 FT
Asia/Pacific
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Three Stacked 6 Element 10 Meter Yagison 36 Foot Booms; 35, 70 and 105 Feet High
decibels
degr
ees
12 degrees
3 degrees
35 FT/70 FT
70 FT/105 FT
Europe
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Three Stacked 6 Element 10 Meter Yagison 36 Foot Booms; 35, 70 and 105 Feet High
decibels
degr
ees
8 degrees
2 degrees
35 FT/70 FT
70 FT/105 FT
Asia/Pacific
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!
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 patternsthat cover the full range of needed elevation anglesStacked Yagis require a tower 70 to 100 feet tall
Tip #3: Use switchable stacks of three Yagis to select broadnull-free radiation patterns for either Europe or Asia/Pacific