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Re: Topband: Inverted-L question

To: topband@contesting.com
Subject: Re: Topband: Inverted-L question
From: Michael Tope <W4EF@dellroy.com>
Date: Thu, 21 Dec 2023 17:37:47 -0800
List-post: <mailto:topband@contesting.com>
Remember, Steve, for a given frequency more capacitance equals less capacitive reactance [Xc = 1/(2*pi*f*c)]. At 1825 KHz, 5300 pf is only 16.5 ohms reactance. That means you are only offsetting a small amount of inductive reactance. Where you should be more concerned is when the series capacitance is very small. That is when capacitive reactance (Xc) gets large and the RF voltage across the series capacitor can get very high.

73, Mike W4EF..............

On 12/20/2023 5:43 PM, Steve Muenich wrote:
I have an Inverted-L question that hopefully someone can answer for me.

I  installed the 160m  wire to the 80 ft level on a 100 ft Rohn 45 tower
with top mounted yagis.
The horizontal (sort of) portion is approx 45ft long.
The wire starts at 80 ft down approx 5 ft from tower and when it gets to
the match box the bottom of the wire is about 10ft away from tower.

I have about 50 or so 120 ft long radials.

I am able to get a X=0, R=52. SWR 1.19:1 tune according to my RE Zoom using
load shunt match at base of tower.

My question is why do I need so much series capacitance (5300pf) with
parallel inductance approx 8uh?

Everything is working fine, but I am wanting to understand why I am needing
so much series capacitance? Does this indicate an issue I need to resolve?

TIA,

Steve, NA5C
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