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Re: LF: Re: Drooping top loading

To: [email protected]
Subject: Re: LF: Re: Drooping top loading
From: "Rik Strobbe" <[email protected]>
Date: Tue, 22 Oct 2002 13:57:35 +0200
In-reply-to: <[email protected]>
References: <000001c2793a$fcd867a0$276336d2@xtr743187> <DDC408CAE72CD511827A0002A5131CD6D9F7E9@exc_wil08>
Reply-to: [email protected]
Sender: <[email protected]>
John, G4CNN, did some extensive calculations on drooping toploads (umbrella antennas). A summary of his work and a link to the webpage with all info can be found at :
http://www.qsl.net/on7yd/136ant.htm#Umbrella

73, Rik  ON7YD

At 12:16 22/10/2002 +0200, you wrote:
To All from PA0SE

In order to find  the effect of drooping top load wires upon the radiation resistance I modelled an umbrella antenna using K6STI's antenna simulation program Antenna Optimizer.

The antenna modelled consists of a vertical wire of 10 m with at the top four wires of 10 m each in the directions N, E, S and W.  The wires include an angle of alpha degrees with the horizontal.  All wires have a diameter of 1.5 millimetres.  The antenna is erected over perfect ground.

Alpha         Rrad      Capacitance
(degrees)  (mohm)      (pF)

 0                        26                   256   (horizontal top wires)

20                       18                   254

40                       12                   250

60                         8                   237

80                         8                   175 

73, Dick, PA0SE
JO22GD
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