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Message-ID: <025201c6e9d8$16b4e740$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><01a401c6e96a$39b97b20$e9ce28c3@captbrian> <20061006223332.da7rnmsp1h0cc0s4@webmail3.kuleuven.be>
Date: Sat, 7 Oct 2006 07:16:10 +0100
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Subject: Re: LF: Re: erp ierp VY1JA
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Status: O

thank you ........and is this comparison half-wave antenna vertical or
horizontal ?  Are there limits about how far away is the 'notional
measuring' position .

It seems we can radiate more power on 136 than I thought ;-) 1.6 times in
fact.

Bryan
----- Original Message -----
From: "Rik Strobbe" <Rik.Strobbe@fys.kuleuven.be>
To: <rsgb_lf_group@blacksheep.org>
Sent: 06 October 2006 21:33
Subject: Re: LF: Re: erp ierp VY1JA


Hello Bryan,

ERP, EIRP, EMRP ... It's just a matter of what reference antenna you take

ERP is the power which would be required to be fed to an 1/2 WAVE
DIPOLE 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 FEEDING 1
WATT INTO THE ANTENNA.

EIRP: as above but replace 1/2 WAVE DIPOLE by ISOTROPIC

EMRP: as above but replace 1/2 WAVE DIPOLE by VERTICAL MONOPOLE

73, Rik  ON7YD

Quoting captbrian <captbrian@ukonline.co.uk>:

> 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 ?
>>
>>
>
>
>


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