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Re: LF: Finbar's Compact 500kHz Vertical

To: [email protected]
Subject: Re: LF: Finbar's Compact 500kHz Vertical
From: Rik Strobbe <[email protected]>
Date: Tue, 17 Jun 2008 15:19:35 +0200
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Dear HaJo,

But in general I feel that antenna height should not be disregarded. Even with equal ERP sky waves may develop better from higher aerials.


I guess that the only cause that 2 antennas fed with the same ERP produce different signals is a difference in the (vertical) radiation pattern, ie. the takeoff angle.
I simulated a 30m, 10m and 3m vertical (at 502kHz) with mmana_gal and found only very small differences: from 18.2 degrees for the 30m vertical to 18.6 degrees for the 3m vertical. This for a uniform ground with a conductivity of 10mS/m.
Making the ground poor (1mS/m) results in a takeoff angle of about 26 degrees (+/- a few tenths depending on the height).
Increasing the conductivity to 100mS/m reduces the takeoff angle to 12-13 degrees.

73, Rik  ON7YD - OR7T

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