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The Extended Oblong for the Shortwave Bands
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The Extended Oblong for the Shortwave Bands
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The 1-λ-Oblong has a gain of 2,6 dBd. We can
increase the gain with a greater circumference.
The highest gain with 3,6 dBd will be in the case of 1,32 λ length and a relation of the sides of 0,16 : 0,5 λ. The feedpoint impedance is 72 + j 660 Ω. Therefore we need a matching network. Better is an ATU and the feeding with a Wireman-twin-cable. In that case we can use the extended Oblong for more than one band. An example for such an antenna is shown right. This is an extended Oblong for 24,9 MHz. The antenna can be used for 10m, 15m and 17m, too. |
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The table shows the gain and the impedance at
XX for the 24,9-MHz-Extended Oblong. Feeding with Wireman-cable and an
Antenna-Tuner.
As a support a glass-fibre mast or a metallic mast can be used, mount the wires insulated! |
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The elevation plot above real ground with medium conductivity. The antenna is mounted 5 m above the ground with the lower part of the loop.
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