Sunday, December 29, 2013

H antenna

It is known that a single dipole antenna tuned neslishkom has a high gain. But if you use two of these antennas connected a phased power line, then we can increase the gain of the antenna. The result is an antenna system comprising two types of dipole antennas, is reminiscent of the Latin letter h and with the name of "lying h". This antenna (lying h) feeding points has high input impedance and it soglosovat to the power supply line of arbitrary length requires use quarter wave transformer. Antenna type "bream h" has exactly takuyuzhe radiation pattern in the horizontal plane as the normal dipole antenna. But the radiation pattern in the vertical plane in the investigation narrows the location of two dipoles of each other and that this expense and get a win to be reinforced. But this antenna system has its drawbacks - namely, suspension height. Necessary to lower the dipole antenna "lying h" was at the height of not less than L / 2 + height of the top of the dipole. The approximate gain of the antenna "lying h" 5-6 dB! And it is much more than a single dipole. The figure shows the dimensions of the antenna "lying h" for three ranges of 14, 21, 28 MHz. As the supply line used by the resonant power line, it Is located horizontally to a measure on the longer L / 2. For this it is necessary to use another mast. Radiation pattern is the range of frequencies used.

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