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Date: Tue, 18 Jan 2011 16:10:02 +0000
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From: Andy Talbot <andy.g4jnt@gmail.com>
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Subject: Re: LF: VLF Earth Mode does NOT need an NoV - official at last
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Which raises the issue of the antennas for ULF Submarine comms.   Could it
be said that feeders of hundreds of km length terminated to ground at the
far end are used solely to get a wide spacing in the ground with the feed
itself not contributing to the radiation.    In which case the resulting
ground mode comms must pass right though the earth - including its iron
core.  No, perhaps not.

But it makes you think - when does earth mode - non-licensable -  become
radiative from the loop of feeder and ground return path?

Andy
www.g4jnt.com




On 18 January 2011 15:44, Chris Trayner <C.Trayner@leeds.ac.uk> wrote:

> Hi Roger,
>
> On 2011 Jan 18, at 15:11, Roger Lapthorn wrote:
>
> > Today I received this letter from OFCOM, which clarifies the legality of
> operating so called "earth mode" (conduction/induction via the ground)
> experiments at frequencies below 9kHz in the UK. Note the sentence in Paul's
> letter saying, "We would not normally issue NoVs for communications using
> non-wireless telegraphy apparatus/stations i.e.  where you rely only on
> conducted emissions and where there are no intentional radiated emissions.".
>
> Maybe.
>
> Saying that they don't normally issue NoVs could mean that NoVs aren't
> needed, or that they are needed but that OFCOM would rarely grant one.
>
> I suspect that their intended interpretation is what you say, and that they
> simply haven't written it unambiguously. I'm willing to say this in your
> defence in court ;-)
>
> 73,
> Chris G4OKW
>
> -----------------------
> Dr Chris Trayner
> School of Electronic & Electrical Engineering,
> The University of Leeds,
> Leeds LS2 9JT, United Kingdom
> Tel: +44 113 34 32053
> Fax: +44 113 34 32032
>
>
>
>
>
>

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<div>Which raises the issue of=A0the antennas=A0for ULF Submarine comms.=
=A0=A0=A0Could it be said that=A0feeders of hundreds of km length terminat=
ed to ground at the far end are used solely to get a wide spacing in the=
 ground with the feed itself not contributing to the radiation.=A0=A0=A0=
=A0In which case the resulting ground mode comms must pass right though th=
e earth - including its iron core.=A0 No, perhaps not.</div>

<div>=A0</div>
<div>But it makes you think - when does earth mode - non-licensable - =A0b=
ecome radiative from the=A0loop=A0of feeder and ground return path?</div>
<div>=A0</div>
<div>Andy</div>
<div><a href=3D"http://www.g4jnt.com/">www.g4jnt.com</a></div>
<div>=A0</div>
<div><br><br>=A0</div>
<div class=3D"gmail_quote">On 18 January 2011 15:44, Chris Trayner <span=
 dir=3D"ltr">&lt;<a href=3D"mailto:C.Trayner@leeds.ac.uk">C.Trayner@leeds.=
ac.uk</a>&gt;</span> wrote:<br>
<blockquote style=3D"BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8e=
x; PADDING-LEFT: 1ex" class=3D"gmail_quote">Hi Roger,<br>
<div class=3D"im"><br>On 2011 Jan 18, at 15:11, Roger Lapthorn wrote:<br><=
br>&gt; Today I received this letter from OFCOM, which clarifies the legal=
ity of operating so called &quot;earth mode&quot; (conduction/induction vi=
a the ground) experiments at frequencies below 9kHz in the UK. Note the se=
ntence in Paul&#39;s letter saying, &quot;We would not normally issue NoVs=
 for communications using non-wireless telegraphy apparatus/stations i.e.=
 =A0where you rely only on conducted emissions and where there are no inte=
ntional radiated emissions.&quot;.<br>
<br></div>Maybe.<br><br>Saying that they don&#39;t normally issue NoVs cou=
ld mean that NoVs aren&#39;t needed, or that they are needed but that OFCO=
M would rarely grant one.<br><br>I suspect that their intended interpretat=
ion is what you say, and that they simply haven&#39;t written it unambiguo=
usly. I&#39;m willing to say this in your defence in court ;-)<br>
<br>73,<br>Chris G4OKW<br><br>-----------------------<br>Dr Chris Trayner<=
br>School of Electronic &amp; Electrical Engineering,<br>The University of=
 Leeds,<br>Leeds LS2 9JT, United Kingdom<br>Tel: +44 113 34 32053<br>Fax:=
 +44 113 34 32032<br>
<br><br><br><br><br></blockquote></div><br>

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