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Date: Tue, 23 Feb 2010 18:25:39 +0100
From: "John RABSON" <john.rabson@numeo.fr>
To: rsgb_lf_group@blacksheep.org
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Subject: LF: Re: VLF_8.79 kHz
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Trying again.

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On 23/02/2010 at 14:16 John RABSON <john.rabson@numeo.fr> wrote:

From: John RABSON <john.rabson@numeo.fr>
To: rsgb_lf_group@blacksheep.org
Date: Tue, 23 Feb 2010 15:51:00 +0100=20
Subject: Re: LF: VLF_8.79 kHz



>My LF ground system consists of nine rods each 1 m long, separated by
>about 2 m.  if I connect them in parallel the inductance at 980 Hz is
>about 7=B5H, and the resistance is about 25 ohms.  This suggests that, at
>the frequencies we are considering, this is an essentially resistive
>termination and we don't need to cancel out the reactive part. =20
>
>If we place a similar setup at the other end of a long wire we should see
>of the order of 50 ohms.  Given that we are working at audio frequency,
>perhaps the step-up transformer from 8 ohms could use conventional soft
>iron laminations.  At 50 Hz, my colleagues used to use a rule of thumb of
>20VA per pound of laminations but I can't remember how this figure varied
>with frequency.
>
>Can any audio power engineers please comment?
>
>73
>John F5VLF

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