The first figure shows a conventional antenna Delta with dimensions for a range of 40 meters. The size of the delta can be calculated by the formula L = 304 / F: L - perimeter of the delta, F - frequency at which it is set. At the point of connection of the coaxial cable included tuning loop length of 80 centimeters. Setting the delta is produced by this train on a minimum SWR. The antenna radiates perpendicularly to the antenna plane. Increase the gain of the delta can be placed at a distance L / 4 from the existing framework of another of the same frame of the same length. Delta gain increases due to the fact that one performs the role of the delta frame vibrator and the other reflector (second figure), i.e. the antenna is unidirectional. In order to change the direction of emission of the delta to the framework necessary to connect an additional antenna loop length L / 4 from the same coaxial cable, and set the switch (third picture). Cable length of frames to loop can be arbitrary. This antenna system can operate only on one range. Strengthening the double delta of about 7 dB. For a more exact matching antenna tuner is needed.
The distance between the borders of the delta in meters:
28 MHz - 2.65
21 MHz - 3.54
14 MHz - 5.32
7 MHz - 10.64
3.6 MHz - 20.2
Loop length in meters:
28 MHz - 1.75
21 MHz - 2.34
14 MHz - 3.52
7 MHz - 7.02
3.6 MHz - 13.33
(Dimensions loop length for the cable impedance of 75 ohms for the other cables needed and stored in the velocity factor.)
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