DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=btinternet.com;
  h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE;
  b=swxlmX5u6e6vcErk7E7iSehYi13VBIfwtJgye3sW9jJ8FK2Pj5KCAkW2Smv4iheZ1ImOj7FL6bCmj3ycWselsIRuD2fOwpRaykyVn265/bMumZUtO+8oCko3APZX5yYf+tgHePbJKkFqSRuWJI18jRfxtT5RqvloUHNSlHE97Eg=  ;
Message-ID: <001301cad1a5$a78bda90$0901a8c0@lark>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <o2kfc7eccec1004010402n7f00e1c3l8b88ea090c0fb8bb@mail.gmail.com> <001d01cad190$aa92e590$0901a8c0@lark> <n2kfc7eccec1004010605n95ffca10ia8bacd2ef2049820@mail.gmail.com>
Date: Thu, 1 Apr 2010 15:12:05 +0100
MIME-Version: 1.0
DomainKey-Status: good (testing) 
Subject: Re: LF: Re: E-Field Probe calibration question
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org


You probably need input from Jim here......I will watch with interest. You
will find the loop calculation in your Terman..............What no Terman!!
call youself an injumier??
:-))
Alan


----- Original Message ----- 
From: "Andy Talbot" <andy.g4jnt@googlemail.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, April 01, 2010 2:05 PM
Subject: Re: LF: Re: E-Field Probe calibration question


> Hi Alan + All...
>
> Actually its a bit more complicated on its own...   The physical length of
> the element is 0.75m, which is appreciably longer than the electrical
> effective length.   And I'm betting a chunk of that difference is made up
by
> having a series resistor in the output circuitry to give a 50 ohm source
> impedance and help stability but reducing voltage gain to below unity.  If
> 50R in series, there is an immediate -6dB  halving the length.    If my
> original dipole concept *were* to apply, then the other half of the leg
> caused by the car would also be affected by the attenuation.
>
> But it appears from your comments so far the argument doesn't apply in
which
> case the 0.15m length still holds.   How do the EMC measurement community
do
> it, as their measurements have to be valid in law and could be held up to
> scrutiny?
>
> Now, what was the voltage from an untuned loop, again ;-?
>
> Andy
> www.g4jnt.com
> Mostly retired inguneer
>
>
> On 1 April 2010 12:44, Alan Melia <alan.melia@btinternet.com> wrote:
>
> > Hi Andy maybe I dont read it right, but if that is an E-field probe it
is
> > not a "dipole" The input capacitance senses the voltage at two points on
> > the
> > wavefront. The ground plane is, I believe, irrelevant. You just need
> > another
> > capacitance separated from the "probe" to reference to voltage to. See
> > Renato's balanced probe (www.vlf.it)  In your case this is the
car.....but
> > it could be the size of a dinky toy.The area of the wavefront
intercepted
> > by
> > the probe or the ground reference does not affect the terminal
> > voltage.....as I see it.................of course I might just be wrong
cos
> > i am really a scientist not an enjuneir!!
> >  :-))
> > Alan
> >
>