MY DOUBLE BOOM YAGI ANTENNAS FOR 144 MHZ
This is a little bit unusual approach to making high gain antennas. The point is to build two vertically stacked yagi antennas, which stacking distance is small.. The reflector, the radiator and the first director are common for both yagis.
The small distance stacking gives not so great gain increase. It is usually around 1 dB over a single yagi (maximum 1.5 dB), but there are other benefits of such configuration.
Because the radiator is common for two antennas, there is no need for phasing harness, and the associated gain loss in it is eliminated,
Vertical radiating pattern is narrower than horizontal (and much cleaner), what is very suitable for DXing.
Close stacking enables better SWR curve and bigger working bandwidth.
As seen, the booms should be slightly bent toward each other for best performance. The vertical distance after bending is not critical, so a little error in bending is negligible. However, the horizontal distance between elements should be kept very precise, as given in the tables for every particular antenna. This means, the element distance/position is given on the centerline between the booms and should be converted into vertical projections on both booms.
Every antenna model has so called LFA radiator. You can see the title `My LFA yagis for 144 MHz` how to build it.
One can say this configuration is hard for building. No, it is not! Both booms strengthen each other, and both booms are additionally reinforced by mounting on a vertical frame holder. At the ends, both booms are finally squeezed to make the necessary boom bending, which gives some more strength. You can, even, use a very small diameter boom.
I built a 8 meter long double boom yagi for 50 MHz using Ø25 mm Aluminum tubes, 1 mm thick. This antenna was standing on the tower for three years with no problems with strongest winds at all. Note, the Ø25 mm tube, 1 mm thick, 6 meter long, is just 1 kilogram of Aluminum. This antenna gain was nearly 14 dBi. For such gain level, a classic style yagi should be 11 to 12 meters long - which means much thicker boom tube, plus boom reinforcements.
DOUBLE BOOM YAGI ANTENNAS FOR 144 MHz – YU7XL
(INSERTED DATA FOR YU7EF ANTENNAS FOR COMPARISON)
|
ANTENNA TYPE |
No of ele |
Ǿ (mm) |
Length (mm) |
Type |
Gain (dB) |
F/B (dB) |
F/Sh (dB) |
F/Sv (dB) |
H lobe (◦) |
V lobe (◦) |
TA (◦K)* |
G/T (dB)* |
Central f (MHz) |
Δf (SWR=1.5) |
|
|
Lower |
Upper |
||||||||||||||
|
EF0206-5 |
6 |
5 |
2377 |
Classic 50Ώ |
11,91 |
25,74 |
24,52 |
14,37 |
46,0 |
55,2 |
283,0 |
-12,61 |
144,400 |
140,200 |
145,300 |
|
11,84 |
25,74 |
24,52 |
14,37 |
46,0 |
55,2 |
283,3 |
-12,68 |
||||||||
|
11 |
10 |
3105 |
LFA |
13.88 |
24.92 |
16.62 |
19.37 |
40.2 |
39.2 |
240.1 |
-9.92 |
144.500 |
138.700 |
146.400 |
|
|
13.85 |
24.96 |
16.60 |
19.38 |
40.2 |
39.2 |
240.5 |
-9.96 |
||||||||
|
11 |
8 |
3105 |
LFA |
13.82 |
25.23 |
17.00 |
19.18 |
40.4 |
39.8 |
239.1 |
-9.97 |
144.500 |
139.300 |
146.400 |
|
|
13.79 |
25.25 |
16.98 |
19.19 |
40.4 |
39.8 |
239.6 |
-10.00 |
||||||||
|
11 |
6 |
3105 |
LFA |
13.71 |
23.38 |
18.03 |
18.82 |
41.2 |
40.8 |
239.3 |
-10.08 |
144.500 |
139.850 |
146.500 |
|
|
13.67 |
23.36 |
18.00 |
18.83 |
41.0 |
40.8 |
239.9 |
-10.13 |
||||||||
|
11 |
5 |
3105 |
LFA |
13.74 |
24.29 |
17.81 |
19.07 |
41.0 |
40.6 |
238.0 |
-10.03 |
144.500 |
139.550 |
146.400 |
|
|
13.68 |
24.27 |
17.77 |
19.09 |
41.0 |
40.6 |
238.8 |
-10.10 |
||||||||
|
EF0207-5 |
7 |
5 |
3274 |
Classic 50Ώ |
12,95 |
25,07 |
24,91 |
17,25 |
42,4 |
48,8 |
255,9 |
-11,13 |
144,300 |
140,400 |
145,100 |
|
12,85 |
24,85 |
24,82 |
17,20 |
42,2 |
48,6 |
256,8 |
-11,25 |
||||||||
|
13 |
10 |
3805 |
LFA |
14.62 |
22.00 |
15.43 |
18.38 |
37.4 |
35.2 |
232.5 |
-9.04 |
144.500 |
141.400 |
146.400 |
|
|
14.59 |
21.96 |
15.41 |
18.39 |
37.4 |
35.2 |
233.0 |
-9.08 |
||||||||
|
13 |
8 |
3805 |
LFA |
14.57 |
23.45 |
15.84 |
18.15 |
37.6 |
35.6 |
231.9 |
-9.08 |
144.500 |
141.350 |
146.300 |
|
|
14.53 |
23.37 |
15.82 |
18.16 |
37.7 |
35.6 |
232.6 |
-9.14 |
||||||||
|
13 |
6 |
3805 |
LFA |
14.50 |
23.63 |
16.38 |
17.95 |
37.8 |
36.2 |
233.4 |
-9.18 |
144.500 |
141.050 |
146.500 |
|
|
14.45 |
23.54 |
16.34 |
17.96 |
37.8 |
36.2 |
234.2 |
-9.25 |
||||||||
|
13 |
5 |
3805 |
LFA |
14.52 |
24.14 |
16.23 |
19.6 |
38.0 |
36.2 |
230.7 |
-9.11 |
144.500 |
141.500 |
146.200 |
|
|
14.46 |
24.02 |
16.29 |
19.67 |
37.8 |
36.0 |
231.8 |
-9.19 |
||||||||
|
EF0208-5 |
8 |
5 |
3900 |
Classic 50Ώ |
13,52 |
22,20 |
22,07 |
15,33 |
40,0 |
45,0 |
248,2 |
-10,43 |
144,200 |
141,220 |
145,490 |
|
13,45 |
22,20 |
22,07 |
15,33 |
40,0 |
45,0 |
249,2 |
-10,51 |
||||||||
|
EF0209-5 |
9 |
5 |
4490 |
Classic 50Ώ |
14,06 |
21,78 |
22,47 |
16,64 |
37,8 |
42,2 |
239,8 |
-9,74 |
144,200 |
140,100 |
145,480 |
|
13,99 |
21,78 |
22,47 |
16,64 |
37,8 |
42,2 |
240,9 |
-9,83 |
||||||||
|
15 |
10 |
4505 |
LFA |
15.24 |
24.76 |
14.90 |
17.27 |
35.0 |
32.0 |
231.1 |
-8.40 |
144.500 |
141.900 |
146.400 |
|
|
15.21 |
24.67 |
14.89 |
17.27 |
35.0 |
32.0 |
231.7 |
-8.44 |
||||||||
|
15 |
8 |
4805 |
LFA |
15.37 |
24.55 |
16.19 |
16.43 |
34.6 |
32.0 |
231.4 |
-8.27 |
144.500 |
140.000 |
146.450 |
|
|
15.33 |
24.51 |
16.17 |
16.43 |
34.6 |
32.0 |
232.1 |
-8.33 |
||||||||
|
15 |
6 |
4805 |
LFA |
15.25 |
24.55 |
17.11 |
16.16 |
35.2 |
32.9 |
230.5 |
-8.38 |
144.500 |
140.150 |
146.650 |
|
|
15.20 |
24.51 |
17.08 |
16.16 |
35.2 |
32.8 |
231.4 |
-8.44 |
||||||||
|
15 |
5 |
4805 |
LFA |
15.20 |
25.06 |
17.45 |
16.08 |
35.4 |
33.2 |
230.1 |
-8.42 |
144.500 |
139.550 |
146.700 |
|
|
15.14 |
25.02 |
17.43 |
16.08 |
35.4 |
33.2 |
331,1 |
--8.50 |
||||||||
|
EF0210-5 |
10 |
5 |
5290 |
Classic 50Ώ |
14,77 |
20,85 |
21,87 |
17,23 |
34,8 |
38,0 |
233,8 |
-8,92 |
144,300 |
140,190 |
145,450 |
|
14,67 |
20,85 |
21,87 |
17,23 |
34,8 |
38,0 |
235,4 |
-9,05 |
||||||||
|
17 |
10 |
5455 |
LFA |
15.95 |
22.38 |
14.46 |
16.45 |
32.2 |
28.5 |
236.3 |
-7.79 |
144.500 |
141.500 |
147.000 |
|
|
15.92 |
22.34 |
14.44 |
16.45 |
32.2 |
28.4 |
237.0 |
-7.83 |
||||||||
|
17 |
8 |
5575 |
LFA |
15.86 |
27.07 |
16.09 |
16.34 |
33.0 |
30.4 |
225.3 |
-7.67 |
144.500 |
140.000 |
146.300 |
|
|
15.82 |
26.99 |
16.08 |
16.34 |
33.0 |
30,2 |
227.0 |
-7.75 |
||||||||
|
17 |
6 |
5575 |
LFA |
15.70 |
26.92 |
16.81 |
15.79 |
33.6 |
31.0 |
229.0 |
-7.90 |
144.500 |
139.600 |
146.800 |
|
|
15.65 |
26.87 |
16.79 |
15.79 |
33.4 |
31.0 |
229.9 |
-7.97 |
||||||||
|
17 |
5 |
5575 |
LFA |
15.67 |
27.25 |
17.09 |
15.61 |
33.6 |
31.2 |
229.3 |
-7.93 |
144.500 |
139.550 |
146.800 |
|
|
15,62 |
27.17 |
17.08 |
15.62 |
33.6 |
31.2 |
230.3 |
-8.00 |
||||||||
|
EF0211B-5 |
11 |
5 |
5980 |
Classic 50Ώ |
15,13 |
29,23 |
21,03 |
17,02 |
33,8 |
36,8 |
229,1 |
-8,47 |
144,300 |
140,600 |
145,210 |
|
15,03 |
29,23 |
21,03 |
17,02 |
33,8 |
36,8 |
230,8 |
-8,60 |
||||||||
|
19 |
10 |
6255 |
LFA |
16.44 |
21.76 |
15.32 |
17.90 |
30.8 |
26.6 |
232.8 |
-7.23 |
144.500 |
140.500 |
146.850 |
|
|
16.40 |
21.71 |
15.32 |
17.89 |
30.6 |
26.6 |
233.6 |
-7.28 |
||||||||
|
19 |
8 |
6225 |
LFA |
16.38 |
24.23 |
15.50 |
18.23 |
31.2 |
27.0 |
226.7 |
-7.17 |
144.500 |
138.000 |
147.100 |
|
|
16.33 |
24.16 |
15.49 |
18.22 |
31.2 |
27.0 |
227.7 |
-7.24 |
||||||||
|
19 |
6 |
6225 |
LFA |
16.34 |
25.36 |
15.73 |
17.75 |
31.4 |
27.6 |
225.8 |
-7.20 |
144.500 |
138.800 |
147.500 |
|
|
16.28 |
25.23 |
15.72 |
17.74 |
31.4 |
27.6 |
227.0 |
-7.28 |
||||||||
|
19 |
5 |
6225 |
LFA |
16.41 |
27.92 |
15.13 |
17.17 |
31.0 |
27.0 |
229.8 |
-7.20 |
144.500 |
139.00 |
147.550 |
|
|
16.33 |
27.68 |
15.12 |
17.14 |
31.0 |
27.0 |
231.2 |
-7.31 |
||||||||
|
EF0211-5 |
11 |
5 |
6325 |
Classic 50Ώ |
15,24 |
20,19 |
22,13 |
18,06 |
33,8 |
36,6 |
226,7 |
-8,31 |
144,100 |
142,500 |
144,750 |
|
15,14 |
20,19 |
22,13 |
18,06 |
33,8 |
36,6 |
228,5 |
-8,45 |
||||||||
|
21 |
10 |
6980 |
LFA |
16.77 |
32.41 |
14.36 |
16.05 |
29.4 |
25.4 |
234.4 |
-6.93 |
144.500 |
138.900 |
147.500 |
|
|
16.73 |
32.24 |
14.35 |
16.03 |
29.4 |
25.4 |
235.1 |
-6.98 |
||||||||
|
21 |
8 |
6980 |
LFA |
16.76 |
28.58 |
14.69 |
16.29 |
29.8 |
25.8 |
234.2 |
-6.94 |
144.500 |
139.900 |
147.500 |
|
|
16.72 |
28.46 |
14.68 |
16.28 |
29.6 |
25.8 |
235.0 |
-6.99 |
||||||||
|
21 |
6 |
6980 |
LFA |
16.76 |
24.12 |
15.43 |
16.61 |
29.8 |
26.0 |
233.3 |
-6.92 |
1.500 |
140.600 |
147.200 |
|
|
16,70 |
24,04 |
15.41 |
16.59 |
29.8 |
26.0 |
234.5 |
-7.00 |
||||||||
|
21 |
5 |
6980 |
LFA |
16.71 |
24.33 |
15.91 |
16.51 |
30.2 |
26.6 |
231.9 |
-6.94 |
144.500 |
140.850 |
147.200 |
|
|
16.64 |
24.22 |
15.87 |
16.49 |
30.2 |
26.4 |
233.2 |
-7.04 |
||||||||
|
EF0212-5 |
12 |
5 |
7260 |
Classic 50Ώ |
15,91 |
21,21 |
20,14 |
16,71 |
31,2 |
33,4 |
224,0 |
-7,59 |
144,300 |
143,300 |
144,820 |
|
15,81 |
21,21 |
20,14 |
16,71 |
31,2 |
33,4 |
226,0 |
-7,73 |
||||||||
|
23 |
10 |
7725 |
LFA |
17.11 |
29.70 |
13.72 |
16.82 |
28.2 |
24.4 |
233.0 |
-6.56 |
144.500 |
137.300 |
147.400 |
|
|
17.07 |
29.60 |
13.71 |
16.82 |
28.2 |
24.4 |
233.8 |
-6.62 |
||||||||
|
23 |
8 |
7725 |
LFA |
17.11 |
29.83 |
24.49 |
16.38 |
28.4 |
24.8 |
232.6 |
-6.56 |
144.500 |
138.100 |
147.000 |
|
|
17.07 |
29.71 |
14.48 |
16.38 |
28.4 |
24.8 |
233.4 |
-6.61 |
||||||||
|
23 |
6 |
7725 |
LFA |
17.00 |
30.29 |
15.57 |
15.87 |
29.0 |
25.6 |
232.1 |
-6.66 |
144.500 |
137.900 |
147.400 |
|
|
16.94 |
30.11 |
15.54 |
15.86 |
29.0 |
25.6 |
233.1 |
-6.74 |
||||||||
|
23 |
5 |
7725 |
LFA |
16.99 |
30.33 |
16.19 |
15.97 |
29.2 |
25.8 |
231.1 |
-6.65 |
144.500 |
137.900 |
147.100 |
|
|
16.93 |
30.17 |
16.17 |
15.97 |
29.2 |
25.8 |
232.3 |
-6.73 |
||||||||
|
EF0213M-5 |
13 |
5 |
7940 |
Classic 50Ώ |
16.12 |
26.47 |
22.13 |
19.27 |
30.6 |
32.6 |
223.9 |
-7.38 |
144.300 |
140.500 |
146.000 |
|
16.00 |
26.31 |
22.11 |
19.25 |
30.6 |
32.6 |
226.2 |
-7.54 |
||||||||
|
EF0213-5 |
13 |
5 |
8150 |
Classic 50Ώ |
16,40 |
19,51 |
19,16 |
16,69 |
29,4 |
31,2 |
224,8 |
-7,12 |
144,300 |
143,660 |
144,620 |
|
16,25 |
19,51 |
19,16 |
16,69 |
29,4 |
31,2 |
227,6 |
-7,32 |
||||||||
|
25 |
10 |
8495 |
LFA |
17.45 |
27.71 |
13.31 |
16.34 |
27.0 |
23.2 |
231.8 |
-6.20 |
144.500 |
137.500 |
147.250 |
|
|
17.41 |
27.64 |
13.30 |
16.33 |
27.0 |
23.2 |
232.6 |
-6.26 |
||||||||
|
25 |
8 |
8495 |
LFA |
17.46 |
28.48 |
14.53 |
16.42 |
27.4 |
24.0 |
231.2 |
-6.18 |
144.500 |
137.700 |
147.600 |
|
|
17.41 |
28.38 |
14.51 |
16.41 |
27.4 |
24.0 |
232.0 |
-6.24 |
||||||||
|
25 |
6 |
8495 |
LFA |
17.32 |
34.95 |
15.84 |
16.23 |
28.0 |
24.8 |
231.5 |
-6.33 |
144.500 |
138.400 |
147.000 |
|
|
17.27 |
34.64 |
15.83 |
16.23 |
28.0 |
24.8 |
232.5 |
-6.39 |
||||||||
|
25 |
5 |
8495 |
LFA |
17.27 |
34.48 |
16.13 |
15.99 |
28.4 |
25.0 |
230.2 |
-6.35 |
144.500 |
138.800 |
146.600 |
|
|
17.20 |
34.06 |
16.11 |
15.98 |
28.4 |
25.0 |
231.3 |
-6.44 |
||||||||
|
EF0214-5 |
14 |
5 |
9100 |
Classic 50Ώ |
16,81 |
22,03 |
20,11 |
17,64 |
28,2 |
30,0 |
220,7 |
-6,63 |
144,300 |
143,720 |
144,620 |
|
16,67 |
22,03 |
20,11 |
17,64 |
28,2 |
30,0 |
223,3 |
-6,82 |
||||||||
|
27 |
10 |
9335 |
LFA |
17.78 |
27.98 |
13.71 |
16.19 |
26.0 |
22.2 |
231.2 |
-5.86 |
144.500 |
137.900 |
147.200 |
|
|
17.73 |
27.89 |
13.70 |
16.17 |
26.0 |
22.2 |
232.0 |
-5.93 |
||||||||
|
27 |
8 |
9335 |
LFA |
17.77 |
30.66 |
15.41 |
15.93 |
26.2 |
22.8 |
230.6 |
--5.86 |
144.500 |
138.100 |
147.650 |
|
|
17.72 |
30.52 |
15.41 |
15.92 |
26.2 |
22.6 |
231.5 |
-5.93 |
||||||||
|
27 |
6 |
9335 |
LFA |
17.65 |
40.14 |
16.10 |
15.84 |
27.0 |
24.0 |
239.5 |
-5.98 |
144.500 |
138.500 |
147.700 |
|
|
17.60 |
39.53 |
16.08 |
15.84 |
27.0 |
23.8 |
231.5 |
-6.05 |
||||||||
|
27 |
5 |
9335 |
LFA |
17.62 |
37.91 |
16.60 |
15.81 |
27.2 |
24.2 |
229.4 |
-5.99 |
144.500 |
138.900 |
147.200 |
|
|
17.56 |
37.35 |
16.59 |
15.81 |
27.2 |
24.0 |
230.6 |
-6.07 |
||||||||
|
EF0215-5 |
15 |
5 |
10060 |
Classic 50Ώ |
17,26 |
20,42 |
17,08 |
16,33 |
26,2 |
27,6 |
223,0 |
-6,22 |
144,200 |
143,750 |
144,460 |
|
17,06 |
20,42 |
17,08 |
16,33 |
26,2 |
27,6 |
226,7 |
-6,49 |
||||||||
|
29 |
10 |
10095 |
LFA |
18.04 |
29.28 |
14.59 |
16.00 |
25.2 |
21.4 |
231.7 |
-5.61 |
144.500 |
138.900 |
146.800 |
|
|
17.99 |
29.22 |
14.59 |
15.97 |
25.2 |
21.4 |
232.5 |
-5.67 |
||||||||
|
29 |
8 |
10095 |
LFA |
18.05 |
28.09 |
14.68 |
15.77 |
25.4 |
21.8 |
233.0 |
-5.62 |
144.500 |
138.700 |
147.630 |
|
|
17.99 |
27.98 |
14.67 |
15.74 |
25.4 |
21.8 |
233.9 |
-5.70 |
||||||||
|
29 |
6 |
10095 |
LFA |
17.96 |
29.17 |
15.62 |
15.48 |
25.8 |
22.6 |
234.0 |
-5.73 |
144.599 |
138.600 |
148.050 |
|
|
17.90 |
29.05 |
15.60 |
15.48 |
25.8 |
22.6 |
235.0 |
-5.81 |
||||||||
|
29 |
5 |
10095 |
LFA |
17.91 |
27.10 |
15.33 |
1.96 |
26.0 |
22.8 |
23.0 |
-5.78 |
144.500 |
138.900 |
147.250 |
|
|
17.84 |
26.96 |
15.31 |
14.95 |
26.0 |
22.8 |
235.2 |
-5.87 |
||||||||