References: <AANLkTi=j-Bp7+YC+527yQ6EBahLUdq6WqYXSGNTk33m7@mail.gmail.com> <59F87B1BA5D04A2F98902CF94C38DB30@JimPC> <8CDB60EE4F8971C-1AD0-3512@webmail-m142.sysops.aol.com> <000001cbe86b$a741e790$0401a8c0@xphd97xgq27nyf>
To: rsgb_lf_group@blacksheep.org
Date: Thu, 24 Mar 2011 07:14:22 -0400
In-Reply-To: <000001cbe86b$a741e790$0401a8c0@xphd97xgq27nyf>
MIME-Version: 1.0
From: Markus Vester <markusvester@aol.com>
Message-Id: <8CDB82BC1CF597E-B4C-C058@webmail-d038.sysops.aol.com>
Subject: Re: LF: Re: Loop TX antennas at VLF?
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Mal,=20

in our context, magnetic stimulation should not be a real problem. Around=
 9 kHz, ICNIRP guidelines (which do include a large safety margin) allow=
 24.4 A/m for occupational exposure and 5 A/m for the general public. A lo=
op wire carrying 100 amps generates a very moderate 8 A/m at 1 m radial di=
stance. On the other hand, 0.35 amps into my loading coil generates about=
 4 A/m at 1 m from the axis.=20

Actual stimulation thresholds are typically two to three orders of magnitu=
de higher. Using ear plugs, I inserted my head into the opening at the col=
d (!) end of the coil for a few seconds. The magnetic field (approximately=
 1000 A/m) produced no perceivable effect.

Best regards,
Markus (DF6NM)


-----Urspr=C3=BCngliche Mitteilung-----=20
Von: mal hamilton <g3kevmal@talktalk.net>
An: rsgb_lf_group@blacksheep.org
Verschickt: Mo., 21. Mrz. 2011, 19:54
Thema: Re: LF: Re: Loop TX antennas at VLF?


Markus
On health grounds I will leave loops alone. Your closing paragraph refers
de mal/g3kev
=20

----- Original Message -----=20
From: Markus Vester=20
To: rsgb_lf_group@blacksheep.org=20
Sent: Monday, March 21, 2011 6:42 PM
Subject: Re: LF: Re: Loop TX antennas at VLF?


...
As the antenna is likely to be built in an inhabited area, you may also wa=
nt to consider that magnetic fields are not shielded very well by most hou=
sing construction materials. They will also penetrate our bodies, with an=
 (at least theoretical) possibility of nerve stimulation in the immediate=
 vicinity of very large AC currents.
...=20

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<font color=3D'black' size=3D'2' face=3D'arial'>
<div>Mal, </div>


<div>&nbsp;</div>


<div>in our context, magnetic stimulation should not&nbsp;be a real proble=
m. Around 9 kHz, ICNIRP guidelines&nbsp;(which do include a large safety=
 margin) allow 24.4 A/m for occupational exposure and 5 A/m for the genera=
l public.&nbsp;A loop wire carrying 100&nbsp;amps&nbsp;generates a very mo=
derate 8 A/m at 1 m radial distance.&nbsp;On the other hand, 0.35 amps int=
o my loading coil generates about&nbsp;4 A/m at 1 m from the axis.&nbsp;</=
div>


<div>&nbsp;</div>


<div>Actual stimulation thresholds are typically two to three orders of ma=
gnitude higher.&nbsp;Using ear plugs, I inserted my head&nbsp;into the ope=
ning&nbsp;at the cold (!)&nbsp;end of the coil&nbsp;for a few seconds. The=
 magnetic field&nbsp;(approximately&nbsp;1000 A/m) produced no perceivable=
 effect.</div>


<div><br>
Best regards,</div>


<div>Markus (DF6NM)<br>
<br>
</div>


<div style=3D"FONT-FAMILY: arial,helvetica; COLOR: black; FONT-SIZE: 10pt"=
>-----Urspr=C3=BCngliche Mitteilung----- <br>
Von: mal hamilton &lt;g3kevmal@talktalk.net&gt;<br>
An: rsgb_lf_group@blacksheep.org<br>
Verschickt: Mo., 21. Mrz. 2011, 19:54<br>
Thema: Re: LF: Re: Loop TX antennas at VLF?<br>
<br>


<div id=3DAOLMsgPart_2_59403c5b-0d03-4db6-9a19-8d7e9ee5a4e2>

<div><FONT face=3DArial>Markus</FONT></div>


<div><FONT face=3DArial>On health grounds I will leave loops alone. Your=
 closing paragraph refers</FONT></div>


<div><FONT face=3DArial>de mal/g3kev</FONT></div>


<div>&nbsp;</div>

<BLOCKQUOTE style=3D"BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PA=
DDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px" dir=3Dltr>

<div style=3D"FONT: 10pt arial">----- Original Message ----- </div>


<div style=3D"FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B=
>From:</B> <A title=3Dmarkusvester@aol.com href=3D"mailto:markusvester@aol=
.com">Markus Vester</A> </div>


<div style=3D"FONT: 10pt arial"><B>To:</B> <A title=3Drsgb_lf_group@blacks=
heep.org href=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_group@blacks=
heep.org</A> </div>


<div style=3D"FONT: 10pt arial"><B>Sent:</B> Monday, March 21, 2011 6:42=
 PM</div>


<div style=3D"FONT: 10pt arial"><B>Subject:</B> Re: LF: Re: Loop TX antenn=
as at VLF?</div>


<div><br>
</div>
<FONT color=3Dblack size=3D2 face=3Darial>

<div>...</div>


<div>As the antenna is likely to be built in an inhabited area, you may al=
so want to consider that magnetic fields are not shielded very well by mos=
t housing construction materials. They will also penetrate our bodies, wit=
h an (at least theoretical) possibility of nerve stimulation in the immedi=
ate vicinity of very large AC currents.</div>


<div>...&nbsp;</div>
</BLOCKQUOTE></FONT></div>
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