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References: <4CA5E86D.1070208@iup.uni-heidelberg.de>
	<376446.30745.qm@web111903.mail.gq1.yahoo.com>
Date: Sun, 3 Oct 2010 13:00:16 +0100
Message-ID: <AANLkTinMfSPjnqpdPosz2zZJ0O8AvE64CLfS9WOZZRKk@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
DomainKey-Status: good (testing) 
Subject: Re: VLF: looking for a simple-to-build sub-9KHz E-probe
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Use your existing or whatever loop, but before any preamp add a high pass
filter.

Take a look at  http://www.g4jnt.com/LF_HPF.gif    for a design using off
the shelf component values for a 50 ohm design with Fc = 6kHz (to allow you
to receive the 6900 kite signals, and provide > 80dB of rejection of 50Hz
and its harmonics.

If you want a another design - for a different Zo, Fc etc -  have a play
with AADE filter designer.   It whiles-away a wet sunday afternoon
(meanwhile checking there are no smoke signals) if nothing else :-)


Andy
www.g4jnt.com


On 3 October 2010 12:31, Daniele Tincani <danieletincani@yahoo.com> wrote:

>  Hello VLF,
>
> just to try to improve a bit my reception at < 9KHz, I'm looking for a
> easy-to-build E-probe design.
> Currently I'm using a very simple system (
> http://www.vlf.it/easyloop/_easyloop.htm) which works very good but
> unfortunately it has to succumb to the intense hum I have all around. In
> fact, I live on the 5th floor of a 6-floors
> jointly-owned building in a sub-urban area (in Livorno, Italy). I have a
> motorway, a railway, electric powerlines, mobile phone antennas, etc. all
> within a few hundreds meters.
> I don't know if an E-probe would survive better than a loop in such an
> hostile enviroment :-) However, a short whip is for sure easier to build and
> to handle than a 70 cm x 70 cm, 40-turns loop like the one I have currently.
> I'm also looking for an homebrew design as off-the-shelf receivers look to
> me a bit costly compared to my VLF budget :-)
> Any suggestions/references?
>
> Best regards
> Daniele
>
>

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<div>Use your existing or whatever loop, but before any preamp add a high=
 pass filter.</div>
<div>=A0</div>
<div>Take a look at=A0 <a href=3D"http://www.g4jnt.com/LF_HPF.gif">http://=
www.g4jnt.com/LF_HPF.gif</a>=A0=A0=A0 for a design using off the shelf com=
ponent values for a 50 ohm design with Fc =3D 6kHz (to allow you to receiv=
e the 6900 kite signals, and provide &gt; 80dB of rejection of 50Hz and it=
s harmonics.</div>

<div>=A0</div>
<div>If you want a another design - for a different Zo, Fc etc=A0- =A0have=
 a play with AADE filter designer.=A0=A0 It whiles-away a wet sunday after=
noon (meanwhile checking=A0there are no smoke signals)=A0if nothing else=
 :-)</div>
<div>=A0</div>
<div><br clear=3D"all">Andy<br><a href=3D"http://www.g4jnt.com">www.g4jnt.=
com</a><br><br><br></div>
<div class=3D"gmail_quote">On 3 October 2010 12:31, Daniele Tincani <span=
 dir=3D"ltr">&lt;<a href=3D"mailto:danieletincani@yahoo.com">danieletincan=
i@yahoo.com</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">
<div>
<div style=3D"FONT-FAMILY: arial, helvetica, sans-serif; FONT-SIZE: 10pt">
<div>Hello VLF,</div>
<div>=A0</div>
<div>just to try to improve a bit my reception at &lt; 9KHz, I&#39;m looki=
ng for a easy-to-build E-probe design.</div>
<div>Currently I&#39;m using a very simple system (<a href=3D"http://www.v=
lf.it/easyloop/_easyloop.htm" target=3D"_blank"><font color=3D"#9136ad">ht=
tp://www.vlf.it/easyloop/_easyloop.htm</font></a>) which works very good=
 but<br>
unfortunately it has to succumb to the intense hum I have all around.=A0In=
 fact,=A0I live on the 5th floor of a 6-floors<br>jointly-owned building=
 in a sub-urban area (in Livorno, Italy). I have a motorway, a railway, el=
ectric powerlines, mobile phone antennas, etc. all within a few hundreds=
 meters.</div>

<div>I don&#39;t know if an E-probe would survive better than a loop in su=
ch an hostile enviroment :-) However, a short whip is for sure easier to=
 build and to handle than a 70 cm x 70 cm, 40-turns loop like the one I ha=
ve currently.</div>

<div>I&#39;m also looking for an homebrew design as off-the-shelf receiver=
s look to me a bit costly compared to my VLF budget :-)</div>
<div>Any suggestions/references?</div>
<div>=A0</div>
<div>Best regards</div>
<div>Daniele<br></div></div><br></div></blockquote></div><br>

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