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Re: Topband: Coax capacitor losses

To: "Peter Wardenier" <Peter.Wardenier@asml.com>,<topband@contesting.com>, "Terry Conboy" <n6ry@arrl.net>
Subject: Re: Topband: Coax capacitor losses
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Thu, 23 Dec 2004 15:47:51 -0500
List-post: <mailto:topband@contesting.com>
> the odd length.)  It would seem that paralleling two of
these stubs would
> give Zi of 0.21 - j 77.75 ohms or about 1/4 the loss
resistance of the
> single 10 meter stub (under 0.02 dB or about 6.3 watts out
of 1500).
>
> Did I miss something?
>
> 73, Terry N6RY

You didn't miss anything Terry. The ESR should be reduced
somewhere less than half of a single stub, and it could be
as much as 1/4 the resistance of a single stub.

You not only have the resistances in parallel (making it
half the ESR and twice the Q), the "conductor length" of
each resistor is also half.

I don't know how paralleling two stubs came out to be the
same, but that conclusion is wrong for certain.

The problems with coaxial capacitors really show up when the
stub passes high current, especially with high values of
capacitance.

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