Introduction

This page presents a series of 3-Element HF antennas that are easily constructed, "easily matched and easily tuned". By "easily matched and easily tuned" it is meant that, these antennas can be constructed and tuned on the ground. When the antenna is finally placed at height, there will only be a small decrease in F/B ratio. But the decrease is small and not worth trying to tune at height.

Note: The feed impedance for these yagi designs is 18-20 Ω. This means that a matching device will be necessary for the driven element, if you want to use 50/75 Ω coax or 75/300/450 Ω Ladder Line. See the web page on 2 and 3 Element Yagi Matching.

3-Element Parasitic Beam
For 6 or 10 Meters
3-Element Parasitic Beam
For 11, 15, or 20 Meters
Power Gain = 7.5 - 8.0 dB
F/B Ration = 20 dB
Radiation Resistance = 22 Ohms
Power Gain = 8.0 - 8.5 dB
F/B Ration = 25 dB
Radiation Resistance = 20 Ohms
Driven Element Length
475/FMHz (ft) || 144.8/FMHz (m)
Director Length
436/FMHz (ft) || 132.9/FMHz (m)
Reflector Length
505/FMHz (ft) || 153.9/FMHz (m)
Element Spacing
185/FMHz (ft) || 56.4/FMHz (m)
Driven Element Length
473/FMHz (ft) || 144.2/FMHz (m)
Director Length
445/FMHz (ft) || 135.6/FMHz (m)
Reflector Length
501/FMHz (ft) || 152.7/FMHz (m)
Element Spacing
140/FMHz (ft) || 42.7/FMHz (m)
Bandwidth for 1.75:1 SWR
1250 KHz at 10 Meters
2100 KHz at  6 Meters
Bandwidth for 1.75:1 SWR
 450 KHz at 20 Meters
 840 KHz at 15 Meters
1070 KHz at 11 Meters
Diameter of Elements
10 Meters = 1-1/2"
6 Meters = 1"
Diameter of Elements
20 Meters = 1-1/2"
15 Meters = 1"
11 Meters = 1"
The table on the right is similar to the table in Bill Orr's1 book. I updated the table to include current references and metric dimensions. The antennas are separated into two groups and have slightly different gains. This is because the bands on the left (6 and 10 Meters) have a greater operating bandwidth (>3% at the design frequency). For these bands, the gain is lowered so that the antenna covers a larger bandwidth. Whereas, the bands on the right (11, 15, and 20 Meters) are much narrower (<3% at the design frequency) and can realize a higher gain and still cover the whole band with an SWR <= 1.75:1.

The antennas in the table are detailed below. For the most part, the text associated with each antenna is pretty generic. However, if there is anything specific about an antenna, it will be listed in the description

3-Element 6 Meter Antenna

The diagram below contains all the information you would need to build a 3-Element 6 Meter antenna. A General Coverage frequency (51.5 MHz) is selected as this provides the best coverage of the 6 Meter band. The SWR chart on the right show the General Coverage antenna's SWR performance, within the 6 Meter band. If you wish to use a center frequency above or below the General Coverage frequency, the Element Length .vs. Frequency chart can be used to determine new element lengths. The chart only lists the length of the driven and director elements. The Element Spacing can be kept the same, as there is very little change (2 inches) across the 6 Meter band. The spacing listed on the diagram is a good mean value.

50
51
52
53
54
Frequency (MHz)
8'
9'
10'
E
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Low Frequency
Coverage
High Frequency
Coverage
Driven Element (A)
Director (D)
Reflector (R)
Top View
R
A
D
3' 7" (1.095 m)
3' 7" (1.095 m)
7.5 dB
Element Diameter = 1"
50
51
52
53
54
Frequency (MHz)
1
1.5
2.0
S
W
R
Low Frequency
Coverage
High Frequency
Coverage
Element Lengths for 50 MHz, 3-Element Parasitic Array.
For Low Frequency Coverage (50-52 MHz) - R = 9′ 10", A = 9′ 4", D = 8′ 7", S = 3′ 7"
For High Frequency Coverage (52-54 MHz) - R = 9′ 6", A = 8′ 11", D = 8′ 2", S = 3′ 7"
For Spot Operation near 50 MHz - R = 10′ 1", A = 9′ 6", D = 8′ 10", S = 3′ 7"
SWR vs Frequency for
3-Element Beam
Resonated at
51 MHz or 53 MHz.

The table below can also be used to determine Driven and Director elements for a frequency other than the General Coverage frequency. Just select your center frequency from the drop-down selector listed under the Frequency catagory. The dimensions for the Driven and Director elements, and the Element Spacing, will automatically be updated.

Gain F/B
Ratio
Rad.
Res.
Frequency DE
Length

475/FMHz
(144.8/FMHz)
Dir
Length

436/FMHz
(132.9/FMHz)
Ref
Length

505/FMHz
(153.9/FMHz)
Element
Spacing

185/FMHz
(56.4/FMHz)
1.75:1 SWR
Bandwidth
Element
Diameter
7.5
to
8.0 dB
20 dB 22 Ω 9' 3-3/4"
2.839 m
8' 6-5/8"
2.606 m
9' 10-7/8"
3.018 m
3' 7-1/2"
1.106 m
2,100 KHz 1"

3-Element 10 Meter Antenna

The diagram below contains all the information you would need to build a 3-Element 10 Meter antenna. A General Coverage frequency (28.75 MHz) is selected as this provides the best coverage of the 10 Meter band. The SWR chart on the right show the General Coverage antenna's SWR performance, within the 10 Meter band. If you wish to use a center frequency above or below the General Coverage frequency, the Element Length .vs. Frequency chart can be used to determine new element lengths. The chart only lists the length of the driven and director elements. The Element Spacing can be kept the same, as there is very little change (3 inches) across the 10 Meter band. The spacing listed on the diagram is a good mean value.

28.0
28.5
29.0
29.5
30.0
Frequency (MHz)
14'
15'
16'
17'
18'
E
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Low Frequency
Coverage
High Frequency
Coverage
Driven Element (A)
Director (D)
Reflector (R)
Top View
R
A
D
6' 6" (2.000 m)
6' 6" (2.000 m)
7.5 dB
Element Diameter = 1-1/2"
28.0
28.5
29.0
29.5
30.0
Frequency (MHz)
1
1.5
2.0
S
W
R
Low Frequency
Coverage
High Frequency
Coverage
Element Lengths for 28 MHz, 3-Element Parasitic Array.
For Low Frequency Coverage (28.0-29.2 MHz) - R = 17′ 7", A = 16′ 7", D = 15′ 2", S = 6′ 6"
For High Frequency Coverage (28.5-29.7 MHz) - R = 17′ 4", A = 16′ 3", D = 14′ 11", S = 6′ 6"
SWR vs Frequency for
3-Element Beam Resonated
at 28.7 MHz or 29.2 MHz.

The table below can also be used to determine Driven and Director elements for a frequency other than the General Coverage frequency. Just select your center frequency from the drop-down selector listed under the Frequency catagory. The dimensions for the Driven and Director elements, and the Element Spacing, will automatically be updated.

Gain F/B
Ratio
Rad.
Res.
Frequency DE
Length

475/FMHz
(144.8/FMHz)
Dir
Length

436/FMHz
(132.9/FMHz)
Ref
Length

505/FMHz
(153.9/FMHz)
Element
Spacing

185/FMHz
(56.4/FMHz)
1.75:1 SWR
Bandwidth
Element
Diameter
7.5
to
8.0 dB
20 dB 22 Ω 16' 6-1/4"
5.037 m
15' 2"
4.623 m
17' 6-3/4"
5.353 m
6' 5-1/4"
1.962 m
1,250 KHz 1-1/2"

3-Element 11 Meter Antenna

The diagram below contains all the information you would need to build a 3-Element 11 Meter antenna. A General Coverage frequency (27.1 MHz) is selected as this provides the best coverage of the 11 Meter band. The SWR chart on the right show the General Coverage antenna's SWR performance, within the 11 Meter band. If you wish to use a center frequency above or below the General Coverage frequency, the Element Length .vs. Frequency chart can be used to determine new element lengths. The chart only lists the length of the driven and director elements. The Element Spacing can be kept the same, as there is very little change (1 inch) across the 11 Meter band. The spacing listed on the diagram is a good mean value.

26.9
27.0
27.1
27.2
27.3
Frequency (MHz)
16'
17'
18'
19'
E
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General Coverage
Operation
Driven Element (A)
Director (D)
Reflector (R)
Top View
R
A
D
5' 2" (1.581 m)
5' 2" (1.581 m)
8.5 dB
Element Diameter = 1"
26.9
27.0
27.1
27.2
27.3
Frequency (MHz)
1
1.5
2.0
S
W
R
General Coverage
Operation
Element Lengths for 27 MHz, 3-Element Parasitic Array.
For General Coverage - A = 17′ 7", D = 16′ 5", R = 18′ 6", S = 5′ 2"
SWR vs Frequency for 3-Element
Beam Resonated at 27.1 MHz.

The table below can also be used to determine Driven and Director elements for a frequency other than the General Coverage frequency. Just select your center frequency from the drop-down selector listed under the Frequency catagory. The dimensions for the Driven and Director elements, and the Element Spacing, will automatically be updated.

Gain F/B
Ratio
Rad.
Res.
Frequency DE
Length

473/FMHz
(144.2/FMHz)
Dir
Length

445/FMHz
(135.6/FMHz)
Refr
Length

501/FMHz
(152.7/FMHz)
Element
Spacing

140/FMHz
(42.7/FMHz)
1.75:1 SWR
Bandwidth
Element
Diameter
8.0
to
8.5 dB
25 dB 20 Ω 17' 5-1/2"
5.321 m
16' 5"
5.004 m
18' 5-7/8"
5.635 m
5' 2"
1.576 m
1070 KHz 1"

3-Element 15 Meter Antenna

The diagram below contains all the information you would need to build a 3-Element 15 Meter antenna. A General Coverage frequency (21.2 MHz) is selected as this provides the best coverage of the 15 Meter band. The SWR chart on the right show the General Coverage antenna's SWR performance, within the 15 Meter band. If you wish to use a center frequency above or below the General Coverage frequency, the Element Length .vs. Frequency chart can be used to determine new element lengths. The chart only lists the length of the driven and director elements. The Element Spacing can be kept the same, as there is very little change (2 inches) across the 15 Meter band. The spacing listed on the diagram is a good mean value.

21.0
21.1
21.2
21.3
21.4
21.5
Frequency (MHz)
20'
21'
22'
23'
24'
E
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General Coverage
Operation
Driven Element (A)
Director (D)
Reflector (R)
Top View
R
A
D
6' 7" (2.014 m)
6' 7" (2.014 m)
7.5 dB
Element Diameter = 1"
21.0
21.1
21.2
21.3
21.4
21.5
Frequency (MHz)
1
1.5
2.0
S
W
R
General Coverage
Operation
Element Lengths for 21 MHz, 3-Element Parasitic Array.
For General Coverage - A = 22′ 5", D = 21′ 0", R = 23′ 8", S = 6′ 6"
SWR vs Frequency for 3-Element
Beam Resonated at 21.2 MHz.

The table below can also be used to determine Driven and Director elements for a frequency other than the General Coverage frequency. Just select your center frequency from the drop-down selector listed under the Frequency catagory. The dimensions for the Driven and Director elements, and the Element Spacing, will automatically be updated.

Gain F/B
Ratio
Rad.
Res.
Frequency DE
Length

473/FMHz
(144.2/FMHz)
Dir
Length

445/FMHz
(135.6/FMHz)
Ref
Length

501/FMHz
(152.7/FMHz)
Element
Spacing

140/FMHz
(42.7/FMHz)
1.75:1 SWR
Bandwidth
Element
Diameter
8.0
to
8.5 dB
25 dB 20 Ω 22' 3-3/4"
6.802 m
20' 11-7/8"
6.396 m
23' 7-5/8"
7.203 m
6' 7-1/4"
2.014 m
840 KHz 1"

3-Element 20 Meter Antenna

The diagram below contains all the information you would need to build a 3-Element 20 Meter antenna. A General Coverage frequency (14.2 MHz) is selected as this provides the best coverage of the 20 Meter band. The SWR chart on the right show the General Coverage antenna's SWR performance, within the 20 Meter band. If you wish to use a center frequency above or below the General Coverage frequency, the Element Length .vs. Frequency chart can be used to determine new element lengths. The chart only lists the length of the driven and director elements. The Element Spacing can be kept the same, as there is very little change (3 inches) across the 20 Meter band. The spacing listed on the diagram is a good mean value.

14.0
14.1
14.2
14.3
14.4
Frequency (MHz)
31'
32'
33'
34'
35'
36'
E
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L
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General Coverage
Operation
Driven Element (A)
Director (D)
Reflector (R)
Top View
R
A
D
10' 0" (3.05 m)
10' 0" (3.05 m)
8.5 dB
Element Diameter = 1-1/2"
13.9
14.0
14.1
14.2
14.3
14.4
Frequency (MHz)
1
1.5
2.0
S
W
R
General Coverage
Operation
CW
Operation
Phone
Operation
Element Lengths for 14 MHz, 3-Element Parasitic Array.
For General Coverage - A = 33′ 5", D = 31′ 5", R = 35′ 4", S = 10′ 0"
SWR vs Frequency for 3-Element
Beam Resonated at 14.15 MHz.

The table below can also be used to determine Driven and Director elements for a frequency other than the General Coverage frequency. Just select your center frequency from the drop-down selector listed under the Frequency catagory. The dimensions for the Driven and Director elements, and the Element Spacing, will automatically be updated.

Gain F/B
Ratio
Rad.
Res.
Frequency DE
Length

473/FMHz
(144.2/FMHz)
Dir
Length

445/FMHz
(135.6/FMHz)
Ref
Length

501/FMHz
(152.7/FMHz)
Element
Spacing

140/FMHz
(42.7/FMHz)
1.75:1 SWR
Bandwidth
Element
Diameter
8.0
to
8.5 dB
25 dB 20 Ω 33' 3-3/4"
10.155 m
31' 4"
9.549 m
35' 3-3/8"
10.754 m
9' 10-1/4"
3.007 m
450 KHz 1-1/2"