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4x7-Element |
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4x7-Element-Yagi built by Dirk, ON1IM |
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The 4x7-Element-Group of Herman, PB0AHX |
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4xYagis in H-configuration Distance in vertical plane is 2,85m and in horizontal plane is 3,00m between the Yagis. You can stack the 4 Yagis with a harness of coax-cables: Use 4x50-Ohm-cable, any length (l1), but all cables must have the same length. At the points X you have a feedpoint impedance of 25Ohm. With a quarter-wave transformer (lambda/4*V) of 2x50Ohm-coax (l2) you transform each side to 100Ohm, by connecting them together at point Y you get the desired 50Ohm for the cable to your shack. |
Horizontal pattern for 4x7-El.- Yagi-Group in H-configuration
Vertical pattern for 4x7-El.- Yagi-Group in H-configuration
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4xYagis vertically stacked This group is a very good configuration for contests: Good horizontal angle of radiation and extermly low vertical elevation angle. Used by several contest-groups in Germany! The stacking distance between all Yagis is 3,00m, not easy to handle! You can stack the 4 Yagis with a harness of coax-cables (75 Ohm). Here is the method of quarterwave-transformers used, too. 4x lambda 5/4 or 7/4*V (l1) to the points X, then with further pieces of lambda 5/4 or 7/4 * V (l2) to the point Y with 50Ohm. You need less cable for this method as with 50Ohm cables and 75-Ohm-coax has lower losses as 50-Ohm-cables. |
Vertical pattern of 4x7-Element-Yagis with a vertical stacking of 3m.
Horizontal pattern is the same as with one Yagi.
