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Re: Topband: 160 Shunt-Fed Tower Readings

To: "'Larry K4AB'" <>, <>
Subject: Re: Topband: 160 Shunt-Fed Tower Readings
From: "Charlie Cunningham" <>
Date: Wed, 10 Dec 2014 20:15:53 -0500
List-post: <">>
N0!!  That's the equivalent series capacitance that correspond to -j5.6ohms
capacitive reactance! It would be much clearer if the analyzer would present
it in that form, since it clearly has determined the sign - since it's
indicating an equivalent capacitance.

Anyway, I stand by what I wrote you, Larry. I'd leave that TX antenna alone!
59.5 ohms real with 1.23;1 vswr IS JUST FINE!  IMO

Have Fun!

Charlie, K4OTV

From: Topband [] On Behalf Of Larry
Sent: Wednesday, December 10, 2014 7:10 PM
Subject: Re: Topband: 160 Shunt-Fed Tower Readings

>I would like to know how you can get 15893pf from a 1000pf capacitor.  That
>has to be a mis-read value there...gary  maybe rounded off to 159pf??

That's a great question.  Where is the analyzer actually getting that

Larry K4AB

On 12/10/14, Tom W8JI <> wrote:
>> I'm concerned about a few things:
>> 1) I'm thinking the antenna is electrically too short.  After all, the
>> Yagi at the top really isn't adding too much top loading.  And I'm
>> thinking
>> adding a couple of top loading wires connected to the tower
>> might be beneficial.
> If you run any power, you will likely start to have problems with arcing
> the Yagi antenna elements where they cross the boom.
> This is because of the poor insulation, and because of the high voltage at
> the boom when on 160.
> The cure for that is to ground the elements to the boom though  air coil
> inductors. Just five or ten uH would work OK, and not upset the antenna
> operation. This would also add 160 top loading.
>> 2) What exactly is the analyzer telling me when it says C:15893pF?
>> I'm far from an engineer, but something tells me that's way high.  Or is
>> it?
> It is meaningless. It just means you are measuring almost where the
> is resonant.
> 73 Tom
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