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Date: Wed, 29 Dec 2010 10:13:36 +0000 (GMT)
From: Chris Osborn <g3xiz@yahoo.co.uk>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: VLF Loading Coil Problems - G3XIZ
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Maybe you're right Andy.
The coil was intermittent and gently moving the turns with a paint brush=
 cured=20
the problem temporarily.
That's why I 'assumed' it was a s/cct turn and subsequently rewound the bo=
ttom=20
section.

I'm now wondering whether the quick-dry varnish I used to cement the fine=
 wire=20
in place has lowered the Q

All suggestions welcome

73
Chris
G3XIZ




________________________________
From: Andy Talbot <andy.g4jnt@gmail.com>
To: rsgb_lf_group@blacksheep.org
Sent: Wed, 29 December, 2010 9:44:33
Subject: Re: LF: VLF Loading Coil Problems - G3XIZ


On a large air cored coil I would have thought a shorted turn would just=
 shift=20
the inductance very slilghtly -  rather than lowering the Q significantly.

Andy
www.g4jnt.com
=20

=20
On 29 December 2010 08:26, Chris Osborn <g3xiz@yahoo.co.uk> wrote:

LF,
>
>Many thanks for all efforts, advice and suggestions from members of the=
 group.
>I shall E-mail them personally within the next few days.
>
>I spent several hours yesterday re-winding a section of my VLF loading co=
il.
>There are abour 1200 turns of  0.2 mm wire which had to be hand wound at=
 a rate=20
>of 4 turns per minute (max).
>
>I was disappointed (to say the least) when the coil resonated at the corr=
ect=20
>frequency but had a very low Q.
>Either there's a short-circuit in the other section of the coil or I've=
=20
>introduced a short into the newly re-wound part.
>In any event I am QRT until I can sort the problem.
>
>I have social engagements today and will take another look at it tomorrow=
.
>
>73
>Chris G3XIZ
>
>
>
>



     =20

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<html><head><style type=3D"text/css"><!-- DIV {margin:0px;} --></style></h=
ead><body><div style=3D"font-family:arial,helvetica,sans-serif;font-size:1=
0pt"><div>Maybe you're right Andy.<br>The coil was intermittent and gently=
 moving the turns with a paint brush cured the problem temporarily.<br>Tha=
t's why I 'assumed' it was a s/cct turn and subsequently rewound the botto=
m section.<br><br>I'm now wondering whether the quick-dry varnish I used=
 to cement the fine wire in place has lowered the Q<br><br>All suggestions=
 welcome<br><br>73<br>Chris<br>G3XIZ<br></div><div style=3D"font-family:=
 arial,helvetica,sans-serif; font-size: 10pt;"><br><div style=3D"font-fami=
ly: times new roman,new york,times,serif; font-size: 12pt;"><font face=3D"=
Tahoma" size=3D"2"><hr size=3D"1"><b><span style=3D"font-weight: bold;">Fr=
om:</span></b> Andy Talbot &lt;andy.g4jnt@gmail.com&gt;<br><b><span style=
=3D"font-weight: bold;">To:</span></b> rsgb_lf_group@blacksheep.org<br><b>=
<span style=3D"font-weight:   bold;">Sent:</span></b> Wed, 29 December, 20=
10 9:44:33<br><b><span style=3D"font-weight: bold;">Subject:</span></b> Re=
: LF: VLF Loading Coil Problems - G3XIZ<br></font><br><div>On a large air=
 cored coil I would have thought a shorted turn would just shift the induc=
tance very slilghtly&nbsp;- &nbsp;rather than lowering the Q significantly=
.<br></div>
<div>Andy</div>
<div><a rel=3D"nofollow" target=3D"_blank" href=3D"http://www.g4jnt.com/">=
www.g4jnt.com</a></div>
<div>&nbsp;</div>
<div><br>&nbsp;</div>
<div class=3D"gmail_quote">On 29 December 2010 08:26, Chris Osborn <span=
 dir=3D"ltr">&lt;<a rel=3D"nofollow" ymailto=3D"mailto:g3xiz@yahoo.co.uk"=
 target=3D"_blank" href=3D"mailto:g3xiz@yahoo.co.uk">g3xiz@yahoo.co.uk</a>=
&gt;</span> wrote:<br>
<blockquote style=3D"border-left: 1px solid rgb(204, 204, 204); margin: 0p=
x 0px 0px 0.8ex; padding-left: 1ex;" class=3D"gmail_quote">
<div>
<div style=3D"font-family: arial,helvetica,sans-serif; font-size: 10pt;">
<div>LF,<br><br>Many thanks for all efforts, advice and suggestions from=
 members of the group.<br>I shall E-mail them personally within the next=
 few days.<br><br>I spent several hours yesterday re-winding a section of=
 my VLF loading coil.<br>
There are abour 1200 turns of&nbsp; 0.2 mm wire which had to be hand wound=
 at a rate of 4 turns per minute (max).<br><br>I was disappointed (to say=
 the least) when the coil resonated at the correct frequency but had a ver=
y low Q.<br>
Either there's a short-circuit in the other section of the coil or I've in=
troduced a short into the newly re-wound part.<br>In any event I am QRT un=
til I can sort the problem.<br><br>I have social engagements today and wil=
l take another look at it tomorrow.<br>
<br>73<br>Chris G3XIZ<br><br><br></div></div><br></div></blockquote></div>=
<br>
</div></div>
</div><br>



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