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Re: [TowerTalk] More Inverted L Information from My Setup

Subject: Re: [TowerTalk] More Inverted L Information from My Setup
From: Terry Conboy <>
Date: Fri, 29 Aug 2008 20:20:54 -0700
List-post: <">>
Depending on how much the top wire slopes down and if the end then 
drops 10 feet straight down, the impedance could be around 50 
ohms.  With a 75 ohm cable, the 75 ohm SWR would be 1.5 and the 
impedance at 1/4 wl down the line would be about 112 ohms.  If Dennis 
measures at this point with a 50 ohm bridge or antenna analyzer, the 
indicated "SWR" would be 2.24.  I'd like to know what he is using to 
measure the "SWR", too.

73, Terry N6RY

At 04:14 PM 2008-08-29, K4SAV wrote:
>Thanks for the new data.  EZNEC says that should be a good match for 75
>ohm line.  The insulated wire makes a significant difference.  I can't
>imagine that you would actually have an SWR of 2.8.  What are you using
>to measure the SWR?  If it is an antenna analyzer you may be suffering
>from the same problem many of us have, overload from AM broadcast
>stations.  Try measuring it with a rig using a little power.
>Jerry, K4SAV
> >I must have left out some pertinent information about my inverted L
> >14 awg insullated wire all the way around.
> >Vertical/L section of the antenna is up and over the top of an oak tree.
> >Radials mount to an 18" dia 1/8" aluminum plate.
> >175' total length radiating section  100' vertical
> >Horizontal section (75') slopes slightly downward for the majority 
> of it's length.  Maybe 10' straight down at the end.
> >No towers in play.


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