From: Rik Strobbe <rik.strobbe@fys.kuleuven.be>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Thread-Topic: Re: Antenna relays - multifilar Litz coil
Thread-Index: AQHRIxWa1Rz6f85eWk21Gt3RNDndg56j5fdI
Date: Thu, 19 Nov 2015 22:08:34 +0000
Message-ID: <7E7DFBB4D102A04DB5ADC88D66628A4A444768AE@ICTS-S-MBX1.luna.kuleuven.be>
References: <7E7DFBB4D102A04DB5ADC88D66628A4A4447680B@ICTS-S-MBX1.luna.kuleuven.be>,<8D2F12C25C90296-17B8-899AB@webmail-vd014.sysops.aol.com>
In-Reply-To: <8D2F12C25C90296-17B8-899AB@webmail-vd014.sysops.aol.com>
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Subject: LF: RE: Re: Antenna relays - multifilar Litz coil
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> I am not sure a (lossless) capacitor in parallel with the coil will lower=
 the  antenna efficiency.

I think it would increase the coil losses, compared to a higher inductance =
coil of same Q, without the capacitor.
 Pcoil =3D I*U/Q
At same radiated power, you'll have the same voltage but higher coil curren=
t due to the extra capacitor.

Hi Marcus,

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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<p>&gt; I am not sure a (lossless) capacitor in parallel with the coil will=
 lower the&nbsp; antenna efficiency.
<br>
</p>
<div style=3D"FONT-SIZE: 16px; FONT-FAMILY: Times New Roman; COLOR: #000000=
">
<div>
<div>I think it would&nbsp;increase the coil losses, compared to a higher i=
nductance coil of same Q, without the capacitor.
</div>
<div>&nbsp;Pcoil =3D I*U/Q</div>
<div>At same radiated power, you'll have the same voltage&nbsp;but higher c=
oil current due to the extra capacitor.</div>
<div>&nbsp;</div>
<div>Hi Marcus,</div>
<div>&nbsp;</div>
<div>indeed, parallel capacitor will increase the&nbsp;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.</div>
<div>&nbsp;</div>
<div>73, Rik&nbsp; ON7YD - OR7T</div>
</div>
</div>
</div>
</body>
</html>

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