Message-ID: <117DD72118254066BE1EC7D918A2AE3B@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
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Date: Thu, 17 Mar 2016 18:56:16 -0000
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Subject: Re: LF: EbNaut from Todmorden
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Status: O

Or to be more accurate ,

You  don't need a  NoV for  ground transmission .. that's not  quite the 
same as
attempting to generate  EM field from a  large loop  :)

--------------------------------------------------
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
Sent: Thursday, March 17, 2016 6:48 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: EbNaut from Todmorden

> I've a vague recollection that someone on the list said that
> you don't need an NoV for an earth antenna?  Can anyone recall?
>
> Yes its Audio  and  not  covered by the  electro magnetic regulations
> 73-G,
> --------------------------------------------------
> From: "Paul Nicholson" <vlf0403@abelian.org>
> Sent: Thursday, March 17, 2016 6:06 PM
> To: <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: EbNaut from Todmorden
>
>>
>> I tried the long wire at ELF - it was useless.  No Schumann and
>> it can't see transients from TLEs.    In fact it was pretty poor
>> at VLF which probably shows how well it couples to the trees.
>> So, not a very good antenna.
>>
>> I took it down.
>>
>> I spotted a place where I could probably put up 200m of wire
>> at about 8 metres, clear of any trees.   It's further from
>> the house though so would need a long coax to reach.  I can
>> borrow some scaffold poles from a neighbour.  Not too far from
>> a muddy spring (we have plenty of those) for a good RF ground.
>> I'll need to buy some coax and some proper antenna wire.
>>
>> Stefan wrote (a week ago):
>>
>> > A T200-2 can be used for 1 kW ...
>>
>> A couple of those will arrive this week.
>>
>> Also was inspired by something that Andy posted recently
>> about PAs powered from rectified mains.  Somewhere in the shed
>> there's a mains isolating transformer and a nice variac.
>>
>> I've a vague recollection that someone on the list said that
>> you don't need an NoV for an earth antenna?  Can anyone recall?
>>
>> I could run a wire for a km across the moors and terminate it
>> in a bog.  There's an industrial audio amplifier in the shed
>> which is good for 4kW.   Such a long earth loop would need
>> quite a high driving voltage.  Also in the shed is a big toroidal
>> transformer, about 20cm diameter by 10cm thick, which might
>> make a hefty audio transformer if the material is up to it.
>>
>> ...
>>
>> I dug the big toroid out.  It has two windings, 400 turns
>> giving 0.98H and 10 turns of 2cm wide copper strip for 395 uH.
>> So about 6.17uH/turns^2.   At 8270Hz 2.44V in gives 101.6V out.
>> The amplifier is too heavy for one person to lift so I can't
>> try it into the xfmr until an unsuspecting friend comes to visit.
>>
>> --
>> Paul Nicholson
>> --
>>
>