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| Keywords: GP-70cm.jpg Selbstgebaute Groundplane-Antenne für das 70cm-Band UHF ground plane antenna for the 70 cm 420 MHz band This is a quarter-wave whip monopole antenna rod at top with four grounded quarter-wave conductors projecting down from the base of the whip to form a ground plane Ground plane antennas have an omnidirectional radiation pattern radiating equal signal strength in all azimuthal directions with the radiated power maximum in a horizontal direction and decreasing with elevation angle to zero on the antenna axis The ground conductors serve to increase radiated power in the horizontal direction to twice the gain of a dipole or 5 19 dB If the ground plane wires extended out horizontally from the base of the monopole the impedance would be half that of the dipole or 36 5 ohms However the downward slant of the ground plane wires serves to increase the antenna impedance so the antenna is a good match for the 50 ohm coaxial cable feedline self-photographed original caption selbst fotografiert 1 2008-09-06 D Derigs wikipedia de D Derigs Original upload log de wikipedia Wdwd CommonsHelper page de wikipedia GP-70cm jpg 2008-09-06 21 14 D Derigs 983×1376× 573698 bytes <nowiki> Andere Versionen </nowiki> Monopole antennas | ||||
