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CHARACTERISTICS
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Typically uses a dipole as the feed element. The rest of the elements are parasitic, usually one reflector and the rest are directors. |
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A Yagi usually produces the most linear polarity gain for materials used |
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The practical gain range of a single Yagi is 6 to 20 dBi |
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The maximum typically bandwidth of a Yagi antenna is 10% ie. At a center frequency of 400 mhz, the bandwidth could be 380 to 420 mHz (40 mHz). |
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Doubling the boom length of a Yagi will increase its gain by 2.2 to 2.3 dB |
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Yagi designs are quite practical to about 3000 mHz |
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The best frequency range for Yagis is 3 to 1500 mHz |
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Modern computer design programs for Yagis provide great flexibility on gain / bandwidth, Front to back and side lobe control and VSWR bandwidth |
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Yagis are easily matched to 50 or 75 Ohm coaxial cable |
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When 2 Yagis are stacked, the main lobe beamwidth is cut in half in the direction of the stack. No change in beamwidth in the other plane |
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When two Yagis are stacked and phased together almost 3 dB gain is possible. The gain goes up by almost 3 dB each time the array size is doubled. Arrays up to 32 Yagis are quite practical and possible |
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It is easy to create circular polarity with Right Hand (RHC) or Left Hand (LHC) circularity |
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A Yagi is easy to use in Polarity Diversity systems |
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Excellent G/T is possible with Yagis and can be confirmed by computer |
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Typical Frequency Ranges
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| HF |
8.0 to 8.2 MHz, 15 to 15.4 MHz, 25.5 to 26 MH |
| VHF |
48 to 50 MHz, 121 to 126 MHz, 135 to 140 MHz, 150 to 165 MHz |
| UHF |
300 to 330 MHz, 400 to 430 MHz, 810 to 894 MHz |
| Microwave |
1400 to 1500 MHz, 1.85 to 1.975 GHz, 2.4 to 2.485 GHz |
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Basic Layout |
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