Message-ID: <EDDB9CDEA0C0422F9A174FEEED6DEB10@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <4C694CC6.3010609@o2.ie> <006401cb3d5a$e4ebca00$4001a8c0@lark>
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Date: Mon, 16 Aug 2010 17:42:21 +0100
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Subject: Re: LF: Re: Earth electrode antenna tests
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Actually : Two earths  joined with  insulated wires are not very  safe in 
the  vicinity of a  ground  strike , as are  insulated 'long'  radials .... 
with a  typical  rise of   250KAmps / micro-sec , 'strange' things happen to 
all  connected at a time  round  T + 100 mS  +/- a bit  ...

Might  be worth reviewing the  dc path from this aspect ?

G..

--------------------------------------------------
From: "Alan Melia" <alan.melia@btinternet.com>
Sent: Monday, August 16, 2010 4:51 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: LF: Re: Earth electrode antenna tests

>
> Hi Tony, why do you think the directivity is wrong? It looks as though 
> they
> are operating like loops with the majority of the loop area in the ground.
> This is a fairly common appreciation of ground "aerials" though Dave 
> Gibson
> doesnt seem to agree
> :-))
>
> Alan
> G3NYK
>
> ----- Original Message ----- 
> From: "Tony" <ei8jk@o2.ie>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Monday, August 16, 2010 3:35 PM
> Subject: LF: Earth electrode antenna tests
>
>
>>   Yesterday I spent some time playing with different antennae.
>> I started by laying out another wire 52m long orientated roughly
>> north/south and then I shortened my original wire also to be 52m and
>> this one is east/west, both terminated with an earth rod.
>> Results were not as expected however as although the two earth electrode
>> antennae show most definite directivity they were the wrong direction.
>>
>> I monitored BBC R. Bristol on 1548 KHz which is about 500 Km due east of
>> me and on the inverted L (tuned VSWR 1.6:1) I could just detect a
>> carrier heterodyne, on the N/S earth electrode antenna it was S1 but on
>> the E/W earth electrode antenna it was S3.
>> RNE5 on 531 KHz about 960 Km due south of me was S3 on the E/W and S8 on
>> the N/S
>>
>> HGA22 (135 KHz) to my east was S4 on the E/W and S1 on N/S
>>
>> Readings were taken about 12:00 utc so most definitely ground wave.
>>
>> I was expecting the directivity to be broadside on the earth electrode
>> antennae, but they seem to behave like a Beverage in that respect, but
>> something that I think I will investigate further, maybe see if there is
>> any difference if I terminate them with a resistor.
>> I'm sure Mal is correct though that they would be useless to TX through
>> but for RX they seem to have possibilities especially after dark as they
>> are a lot quieter.
>>
>> All good fun.
>> 73, Tony, EI8JK.
>>
>
>
>