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It is a two element Yagi-Uda antenna with folded dipole elements, and no director(s). Because of the folded ends, the element lengths are approximately 70% of the equivalent dipole length. The two-element design gives modest directivity (about 2.0 dB ) with a null towards the rear of the antenna, yielding a high front-to-back ratio : Gain up to ...
However, values will be higher than for a Yagi and more closely matched to a 50 Ohm coaxial feed. Lower boom height "A two-element, three-band quad, with elements mounted only 35 feet above ground, will give good performance in situations where a triband Yagi will not." [12] Shorter boom Orr (1996) [13] shows a 10, 15, and 20 meter, 2 element ...
A Yagi–Uda antenna, or simply Yagi antenna, is a directional antenna consisting of two or more parallel resonant antenna elements in an end-fire array; [1] these elements are most often metal rods (or discs) acting as half-wave dipoles. [2] Yagi–Uda antennas consist of a single driven element connected to a radio transmitter or receiver (or ...
A rooftop television antenna, an endfire parasitic array consisting of a combination of a Yagi and log periodic antenna Parasitic array – This is an endfire array which consist of multiple antenna elements in a line of which only one, the driven element, is connected to the transmitter or receiver, while the other elements, called parasitic ...
The addition of parasitic elements gives a diminishing improvement in the antenna's gain. [2] Adding a reflector to a dipole, to make a 2 element Yagi, increases the gain by about 5 dB over the dipole. Adding a director to this, to give a 3 element Yagi, gives a gain of about 7 dB over a dipole.
A Yagi–Uda antenna's maximum directivity is 8.77 dB d = 10.92 dB i. Its gain necessarily must be less than this by the factor η, which must be negative in units of dB. Neither ERP nor EIRP can be calculated without knowledge of the power accepted by the antenna, i.e., it is not correct to use units of dB d or dB i with ERP and EIRP.
Each element is longer than the last, and to maintain accuracy, the later elements are divided into more segments. All measurements in NEC use metres, so the first element is 2 metres wide, running from -1 to 1. The GE line indicates the end of the geometry section. At this point, NEC scans the geometry for overlapping endpoints, which it then ...
Early TV broadcast antennas used "cigar shaped" elements, shown in image of 1939 RCA Empire State Building antenna above. A common shape today is the batwing or superturnstile antenna, used for television broadcasting in the VHF or UHF bands [ 8 ] The batwing shape of each element produces an antenna with wide impedance bandwidth. [ 1 ]