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Date: Thu, 19 Nov 2015 22:33:53 +0000
Message-ID: <CAA8k23SCxsyVfd_U5zgYHsY7FBq6tZ6JWPk9GYKBsnpeUvKjsg@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: RE: Re: Antenna relays - multifilar Litz coil
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That's a very interesting observation, and a simple calculation shows the
way it will move:

If we add some extra || capacitance that is equal to that of the antenna,
the loading coil inductance needs to be halved.   To a rough first
approximation, the number of turns needed will reduce by SQRT(2) since L ~
N^2 , so the length of winding and coil R will lower by this amount too.
So R becomes R/SQRT(2)

Coil circulating current  will double,   so additional loss is 2 / SQRT(2)
SO worse, but not as bad as first thought

'jnt


On 19 November 2015 at 22:08, Rik Strobbe <rik.strobbe@fys.kuleuven.be>
wrote:

>
> H
> indeed, parallel capacitor will increase the coil current, but on the
> other hand you will get resonance with a smaller inductance. I haven't done
> any calculation on the case (yet), but probably both effects (larger
> current vs smaller coil) will more or less compensate each other.
>
> 73, Rik  ON7YD - OR7T
>

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<div dir=3D"ltr">That&#39;s a very interesting observation, and a simple ca=
lculation shows the way it will move:<div><br></div><div>If we add some ext=
ra || capacitance that is equal to that of the antenna, the loading coil in=
ductance needs to be halved. =C2=A0 To a rough first approximation, the num=
ber of turns needed will reduce by SQRT(2) since L ~ N^2 , so the length of=
 winding and coil R will lower by this amount too.=C2=A0 So R becomes R/SQR=
T(2)</div><div><br></div><div>Coil circulating current =C2=A0will double, =
=C2=A0 so additional loss is 2 / SQRT(2)</div><div>SO worse, but not as bad=
 as first thought</div><div><br></div><div>&#39;jnt</div><div><br></div><di=
v><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On 19 November =
2015 at 22:08, Rik Strobbe <span dir=3D"ltr">&lt;<a href=3D"mailto:rik.stro=
bbe@fys.kuleuven.be" target=3D"_blank">rik.strobbe@fys.kuleuven.be</a>&gt;<=
/span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8=
ex;border-left:1px #ccc solid;padding-left:1ex">


<div>
<div style=3D"direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt=
">
<p><br></p><div style=3D"FONT-SIZE:16px;FONT-FAMILY:Times New Roman;COLOR:#=
000000"><div>
<div>H</div>
<div>indeed, parallel capacitor will increase the=C2=A0coil current, but on=
 the other hand you will get resonance with a smaller inductance. I haven&#=
39;t done any calculation on the case (yet), but probably both effects (lar=
ger current vs smaller coil) will more or
 less compensate each other.</div>
<div>=C2=A0</div>
<div>73, Rik=C2=A0 ON7YD - OR7T</div>
</div>
</div>
</div>
</div>

</blockquote></div><br></div></div></div>

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