| Open-sleeve principles | VHF-Duoband principles | Duoband-Yagi 6m/10m | 10m-Dipole+ 3-El.- 6 m | Triband-Yagi 6m/4m/2m | Duoband-Dipol 2m/70cm | 2m/70cm 2+2/3 El. | 2m/70cm 4+5 El. | 2m/70cm 5+8 El. |
Duoband Yagi 2m/70cm with 4 Elements on 2 m
and 5 Elements on 70 cm and one Feedpoint
Version 1: Ultralight with 3,2-mm-Elements
Version 2: With 8- and 10-mm-Elements (see down), built by SQ9VPA
|
The 4-El.-Ultralight-Yagi for 2m can be used on 70cm with an SWR of 1,5 without any changes. The pattern and the currents of the Yagi are shown down. The Yagi has three forward lobes (according to the three current maxima in the 3/2-lambda-radiator) with 5,39dBd - 4,35dBd -5,39dBd gain. We can use this Yagi without any changes on 2m and 70cm. |
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Feeding of the Duoband-Yagi with a coax-choke. here you can see the solution by Emmanuel, LU5HED |
For increasing the gain and for a better pattern we add 5 elements for 432MHz.
 |
The bandwidth is small, the Yagi is designed for the CW-/SSB-part of the 70cm-band near 432MHz. |
 |
Element currents in the Duoband-Yagi on 432MHz Gain 8dBd at 432MHz |
Data of the
Yagi on the two bands for the SSB-Frequencies
|
144,3
MHz |
7,1dBd |
11,5dB |
58,0° |
81,8° |
|
|
Gain |
F/B |
3dB-angle
hor. |
3dB-angle
ver. |
|
432
MHz |
8,09dBd |
9dB |
30,4° |
80,8° |
All elements made with 3,2mm-Aluminium-welding rods, except the radiator (4mm)
|
El.-Nr. |
Element |
Length |
Position |
|
1 |
Reflector
for 2m |
1022
mm |
0
mm |
|
2 |
Reflector
for 70cm |
329
mm |
110mm |
|
3 |
Radiator
2m and 70cm |
977
mm (4mm) |
260
mm |
|
4 |
Director
1 für 70cm |
322
mm |
300
mm |
|
5 |
Director
2 für 70cm |
320
mm |
440
mm |
|
6 |
Director
1 für 2m |
935
mm |
470
mm |
|
7 |
Director
3 für 70cm |
285
mm |
750
mm |
|
8 |
Director
4 für 70cm |
297
mm |
965
mm |
|
9 |
Director
2 für 2m |
915
mm |
985 mm |
 |
The 4/5-El.-Yagi with 8 and 10-mm-Elements (redisigned by SQ9VPA)
|
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The Duoband-Yagi built by Mich, ON8DM |
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|
|
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| Details of the Duoband-Yagi by Bojan, YT2SMS Click on the thumbnails for greater picture! | ||
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The Duoband-Yagi built by Emmanuel, LU5HED
|
|
El.-Nr. |
Element |
Position |
Length |
Length (10 mm) |
|
1 |
Reflector
for 2m |
0
mm |
1013
mm |
1011 mm |
|
2 |
Reflector
for 70cm |
110mm |
343
mm |
332 mm |
|
3 |
Radiator
2m and 70cm |
260
mm |
973 mm (12 mm) |
973 mm (12 mm) |
|
4 |
Director
1 für 70cm |
308
mm |
319
mm |
316 mm |
|
5 |
Director
2 für 70cm |
440
mm |
312
mm |
310 mm |
|
6 |
Director
1 für 2m |
465
mm |
919
mm |
911 mm |
|
7 |
Director
3 für 70cm |
750
mm |
267
mm |
261 mm |
|
8 |
Director
4 für 70cm |
965
mm |
283
mm |
278 mm |
|
9 |
Director
2 für 2m |
985
mm |
879
mm |
870 mm |
