| The purpose of this design is to create an antenna for mobile field purposes. The antenna must correspond follow requirements:
1. To have gain not less the 7-dB. Forward Gain is the main characteristic of the antenna. 2. A wide lobe must be. During a QSO you can hold the antenna by the tail and shaking of the antenna should not result to full ‘failure’ of the communication. |
Figure 1 |
| 3. Simplicity in making and adjustments. An opportunity of fast repair in field conditions.
4. Antenna weight with coaxial cable both must be up to 500 gram. 5. 50-Ohm coax for the feeding must be used.
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Figure 1 shows a design of such antenna. The boom is made of a wooden strip.. Elements and the vibrator are made of 2-mm copper wire (# 12 AWG).
The sizes of elements:
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| The design of antenna vibrator is shown on Figure 2. Coaxial cable has 850-mm length and this one goes along the boom. Soldered place must be protected from weather.
Antenna has weight of 290 gram. SWR (metered by SWR-291) is: at 433- MHz =2:1, at 435-MHz =1:1, at 438-MHz =2:1. The antenna worked very well in the mountains. Also the antenna may be used for stationary work from a fixed QTH. |
Figure 2 |
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Credit Line: http://www.mountain.ru |
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