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Message-ID: <319404.73821.qm@web28106.mail.ukl.yahoo.com>
Date: Sun, 28 Mar 2010 07:25:28 -0700 (PDT)
From: M0FMT <m0fmt@yahoo.co.uk>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: Antenna Matching
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Hi Tim
=A0
Try an air cored=A0transformer (no unobtainium) about 100mm diameter about=
 60 turns of 1mm diameter wire. Using a shorting tap from the antenna end=
 down the coil. Use about 1 to 2 turn loop at the earthy end for your 50oh=
m TX. The earthy end of the coil should be connected to a good earth syste=
m.
This should give a coil about 300yH with a Q of about 400. You don't need=
 a capacitor just tap carefully down the coil. Remember you will have abou=
t 2 kV floating about and 1.5 amps in the up lead with a watt and a bit=A0=
radiated for a 100 watt TX.
=A0
My antenna is up 13m and I use the above arrangement.
=A0
73 es GL petefmt

--- On Sun, 28/3/10, tim hague <m0afj@dsl.pipex.com> wrote:


From: tim hague <m0afj@dsl.pipex.com>
Subject: LF: Antenna Matching
To: rsgb_lf_group@blacksheep.org
Date: Sunday, 28 March, 2010, 11:10


I'm just about to apply for my 500kHz NoV, I've got around 100W of Tx powe=
r available and I'm looking for some information on antenna matching, my=
 Tx antenna is just going to be a 132ft Marconi T with a 50ft vertical sec=
tion, can I get away with just a series tuned matching cct or are the volt=
ages across my matching C going to be very high, I have a wide spaced C ap=
prox 200 to 700pF.

Thanks=A0 Tim M0AFJ




     =20

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<table cellspacing=3D"0" cellpadding=3D"0" border=3D"0" ><tr><td valign=3D=
"top" style=3D"font: inherit;"><DIV id=3Dyiv723899018>
<DIV>
<DIV>Hi Tim</DIV>
<DIV>&nbsp;</DIV>
<DIV>Try an air cored&nbsp;transformer (no unobtainium) about 100mm diamet=
er about 60 turns of 1mm diameter wire. Using a shorting tap from the ante=
nna end down the coil. Use about 1 to 2 turn loop at the earthy end for yo=
ur 50ohm TX. The earthy end of the coil should be connected to a good eart=
h system.</DIV>
<DIV>This should give a coil about 300yH with a Q of about 400. You don't=
 need a capacitor just tap carefully down the coil. Remember you will have=
 about 2 <SPAN>kV </SPAN>floating about and 1.5 amps in the up lead with=
 a watt and a bit&nbsp;radiated for a 100 watt TX.</DIV>
<DIV>&nbsp;</DIV>
<DIV>My antenna is up 13m and I use the above arrangement.</DIV>
<DIV>&nbsp;</DIV>
<DIV>73 es <SPAN>GL</SPAN> petefmt<BR><BR>--- On <B>Sun, 28/3/10, tim hagu=
e <I>&lt;m0afj@dsl.pipex.com&gt;</I></B> wrote:<BR></DIV></DIV>
<BLOCKQUOTE style=3D"BORDER-LEFT: rgb(16,16,255) 2px solid; PADDING-LEFT:=
 5px; MARGIN-LEFT: 5px"><BR>From: tim hague &lt;m0afj@dsl.pipex.com&gt;<BR=
>Subject: LF: Antenna Matching<BR>To: rsgb_lf_group@blacksheep.org<BR>Date=
: Sunday, 28 March, 2010, 11:10<BR><BR>
<DIV class=3DplainMail>I'm just about to apply for my 500kHz NoV, I've got=
 around 100W of Tx power available and I'm looking for some information on=
 antenna matching, my Tx antenna is just going to be a 132ft Marconi T wit=
h a 50ft vertical section, can I get away with just a series tuned matchin=
g cct or are the voltages across my matching C going to be very high, I ha=
ve a wide spaced C approx 200 to 700pF.<BR><BR>Thanks&nbsp; Tim M0AFJ<BR><=
BR></DIV></BLOCKQUOTE></DIV></td></tr></table><br>



     =20

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