18.12.2012 Views

Von: BueschelW@web.de im Auftrag von Wolfgang Bueschel ...

Von: BueschelW@web.de im Auftrag von Wolfgang Bueschel ...

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5070 antenna is of ITU #902 type, like<br />

900-908 type - rhombic horizontals<br />

#902 RH 155/68/40<br />

maybe 5070 kHz range suffers more by UTE services worldwi<strong>de</strong>, or the<br />

horizontal rhombic matches better gain on lower 60 mb edge?<br />

ITU explanation of 902 antenna type<br />

2.8 Type 8: Rhombic antennas<br />

Designation: RH l//h, where:<br />

l : length of one si<strong>de</strong> of the rhombus (m).<br />

: one half of the interior obtuse angle of rhombus.<br />

h : height of rhombus above ground (m).<br />

FIG 7 Horizontal rhombic antenna.<br />

The rhombic antenna has been extensively used for HF communications. It<br />

continues to be used for fixed-services point-to-point links. It has also<br />

been used for HF broadcasting but is no longer recommen<strong>de</strong>d for this<br />

purpose. The antenna consists of four straight wires of the same length l<br />

arranged in the form of a rhombus.<br />

A typical rhombic antenna <strong>de</strong>sign would use si<strong>de</strong> lengths of several<br />

wavelengths and be at a height of between 0.5-1.0 l at the middle of the<br />

operating frequency range.<br />

The rhombic antenna differs from the array of dipoles since it belongs to<br />

the travelling-wave antenna category, i.e. the currents in the conductors<br />

of the antenna are substantially travelling waves originated from the<br />

feeding point and propagating through the wires towards the terminating<br />

resistance.<br />

A consi<strong>de</strong>rable amount of power may be lost in the terminating resistance<br />

and represents the price that has to be paid for some <strong>de</strong>sirable features<br />

such as s<strong>im</strong>plicity of construction, relatively wi<strong>de</strong> bandwidth of operation<br />

and high directivity gain.<br />

(ITU explanation; wb dxld Feb 4)<br />

VATICAN STATE 4004.253 Vatican Radio, 1959 UT, noted in passing with<br />

intervial signal, into talk by a man. Fair.<br />

(David Sharp-NSW-AUS, dxld Jan 22)<br />

Google Earth <strong>im</strong>agery. Some high resolution place.<br />

Another GE <strong>im</strong>age update.<br />

Vatican Radio, Santa Maria di Galeria, 2.7 x 1.8 kilometers wi<strong>de</strong> area.<br />

service entry access<br />

<br />

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