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Message-ID: <01a401c6e96a$39b97b20$e9ce28c3@captbrian>
From: "captbrian" <captbrian@ukonline.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <000701c6e8f1$aff10b10$6801a8c0@Radio> <00c901c6e919$dd77ada0$e9ce28c3@captbrian> <4526310D.3010902@w1tag.com>
Date: Fri, 6 Oct 2006 18:08:41 +0100
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Subject: Re: LF: Re: erp ierp VY1JA
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Gentlemen,

I have long been fully familiar with 'isotropic antenna ' and 'Effective
Radiated Power.' ......indeed I hope no-one can get a transmitting licence
without such knowledge but.........

ERP is the power which would be required to be fed to an isotropic antenna
to achieve the same field strength at the same distance as is generated by
the antenna under discussion in the centre of its main lobe.

for example: an  antenna with a gain of 10db fed with one watt of power has
an ERP of 10 watts.

However "Effective_ Isotropic_ Radiated Power"  is ..........what ?

Bryan


----- Original Message -----
From: "John Andrews" <w1tag@w1tag.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: 06 October 2006 11:33
Subject: Re: LF: Re: erp ierp VY1JA


> Bryan,
>
> As others have pointed out, the "I" is for isotropic, a theoretical
> radiator that sends the same signal in all directions. A 3-D model of
> the radiation pattern would be a sphere. The far field of a dipole has
> no signal off the ends, and hence has gain in the favoured direction (at
> right angles to the dipole). The 3-D model would be a donut (without
> chocolate frosting).
>
> John A.
>
> captbrian wrote:
> > What is I in IERP ?
>
>