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Message-ID: <79966.50780.qm@web28516.mail.ukl.yahoo.com>
Date: Fri, 15 Apr 2011 14:22:12 +0100 (BST)
From: Chris Osborn <g3xiz@yahoo.co.uk>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <BF4A524700075746A6467658DFC7102C88B4A7886C@ICTS-S-EXC2-CA.luna.kuleuven.be>
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Subject: Re: LF: RE: VLF - vertical probe measurements
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Hello Stefan / Rik,
=A0
Thanks for the response.
=A0
I adjust the PA current by varying the drive level=A0to the FET's so the=
 PA supply voltage stays constant.
I should have made that clear.
=A0
73 Chris G3XIZ

--- On Fri, 15/4/11, Rik Strobbe <Rik.Strobbe@fys.kuleuven.be> wrote:


From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
Subject: LF: RE: VLF - vertical probe measurements
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Date: Friday, 15 April, 2011, 14:11








Hello Chris,
=A0
maybe a stupid question (wouldn't be my first one): how do you alter the=
 PA current ?
If you change the PA current by changing the=A0PA voltage then the output=
 power will change more or less with the square of tht PA current (P =3D=
 UxI and you change both U and I), what would=A0result in a linear behavio=
ur between PA current and probe voltage.
=A0
73, Rik=A0 ON7YD=A0- OR7T
=A0


Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.or=
g] namens Chris Osborn [g3xiz@yahoo.co.uk]
Verzonden: vrijdag 15 april 2011 14:40
Aan: LF Group
Onderwerp: LF: VLF - vertical probe measurements








LF,
=A0
Acting on advice I have installed a whip aerial (probe)=A0on top of a mast=
 at the=A0boundary of my property.
This is in order to monitor my VLF transmissions and to provide a referenc=
e level for any system improvements.
=A0
I noticed that the probe's pick-up voltage is directly proportional to=A0m=
y PA's supply current.
Assuming that the PA efficiency doesn't change drastically with current th=
en would I be correct in assuming that the probe's voltage is directly pro=
portional to the radiated power?
=A0
I was expecting a square law relationship . .=20
=A0
73
Chris G3XIZ

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<table cellspacing=3D"0" cellpadding=3D"0" border=3D"0" ><tr><td valign=3D=
"top" style=3D"font: inherit;"><DIV>Hello Stefan / Rik,</DIV>
<DIV>&nbsp;</DIV>
<DIV>Thanks for the response.</DIV>
<DIV>&nbsp;</DIV>
<DIV>I adjust the PA current by varying the drive level&nbsp;to the FET's=
 so the PA supply voltage stays constant.</DIV>
<DIV>I should have made that clear.</DIV>
<DIV>&nbsp;</DIV>
<DIV>73 Chris G3XIZ<BR><BR>--- On <B>Fri, 15/4/11, Rik Strobbe <I>&lt;Rik.=
Strobbe@fys.kuleuven.be&gt;</I></B> wrote:<BR></DIV>
<BLOCKQUOTE style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: rgb=
(16,16,255) 2px solid"><BR>From: Rik Strobbe &lt;Rik.Strobbe@fys.kuleuven.=
be&gt;<BR>Subject: LF: RE: VLF - vertical probe measurements<BR>To: "rsgb_=
lf_group@blacksheep.org" &lt;rsgb_lf_group@blacksheep.org&gt;<BR>Date: Fri=
day, 15 April, 2011, 14:11<BR><BR>
<DIV id=3Dyiv1456471487>
<STYLE></STYLE>

<STYLE><!--#yiv1456471487 P {
MARGIN-TOP:0px;MARGIN-BOTTOM:0px;}
--></STYLE>

<DIV style=3D"FONT-SIZE: 13px; COLOR: #000000; DIRECTION: ltr; FONT-FAMILY=
: Tahoma">
<DIV>Hello Chris,</DIV>
<DIV><FONT face=3Dtahoma size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3Dtahoma size=3D2>maybe a stupid question (wouldn't be my=
 first one): how do you alter the PA current ?</FONT></DIV>
<DIV><FONT face=3Dtahoma size=3D2>If you change the PA current by changing=
 the&nbsp;PA voltage then the output power will change more or less with=
 the square of tht PA current (P =3D UxI and you change both U and I), wha=
t would&nbsp;result in a linear behaviour between PA current and probe vol=
tage.</FONT></DIV>
<DIV><FONT face=3Dtahoma size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3Dtahoma size=3D2>73, Rik&nbsp; ON7YD&nbsp;- OR7T</FONT></=
DIV>
<DIV dir=3Dltr><FONT face=3DTahoma color=3D#000000 size=3D2></FONT>&nbsp;<=
/DIV>
<DIV id=3Dyiv1456471487divRpF185525 style=3D"DIRECTION: ltr">
<HR tabIndex=3D-1>
<FONT face=3DTahoma color=3D#000000 size=3D2><B>Van:</B> owner-rsgb_lf_gro=
up@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Chris Osborn=
 [g3xiz@yahoo.co.uk]<BR><B>Verzonden:</B> vrijdag 15 april 2011 14:40<BR><=
B>Aan:</B> LF Group<BR><B>Onderwerp:</B> LF: VLF - vertical probe measurem=
ents<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>
<TABLE cellSpacing=3D0 cellPadding=3D0 border=3D0>
<TBODY>
<TR>
<TD vAlign=3Dtop>
<DIV>LF,</DIV>
<DIV>&nbsp;</DIV>
<DIV>Acting on advice I have installed a whip aerial (probe)&nbsp;on top=
 of a mast at the&nbsp;boundary of my property.</DIV>
<DIV>This is in order to monitor my VLF transmissions and to provide a ref=
erence level for any system improvements.</DIV>
<DIV>&nbsp;</DIV>
<DIV>I noticed that the probe's pick-up voltage is directly proportional=
 to&nbsp;my PA's supply current.</DIV>
<DIV>Assuming that the PA efficiency doesn't change drastically with curre=
nt then would I be correct in assuming that the probe's voltage is <U>dire=
ctly proportional</U> to the radiated power?</DIV>
<DIV>&nbsp;</DIV>
<DIV>I was expecting a square law relationship . . </DIV>
<DIV>&nbsp;</DIV>
<DIV>73</DIV>
<DIV>Chris G3XIZ</DIV></TD></TR></TBODY></TABLE></DIV></DIV></DIV></BLOCKQ=
UOTE></td></tr></table>

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