Topband: A 160 Meter antenne puzzle

[ZR]

Is the 4x4 pressure treated? Or from a local sawmill and uncured?

Both will have an effect.

Carl
KM1H


----- Original Message ----- 
From: "Glenn Biggerstaff" <ww4b73 at gmail.com>
To: <topband at contesting.com>
Sent: Monday, January 07, 2013 9:30 PM
Subject: Topband: A 160 Meter antenne puzzle


> Hi everybody and happy new year .
> I have what I think is an interesting  antenna riddle . I have some 
> receive  antenna verticals (4) that are selected by relays in pair and the 
> pair is fed back to the shack to a phasing boxing .Each antenna is AL 
> tubing about 30 feet tall, base loaded with an inductor and a resistor 
> very much like ON4UN has for his 4 square receive  array .There is a 1 to 
> 1 balun between the antenna and the feed line . The tubing is insulated 
> with an eight inch length of pvc pipe from  the 4x4 that supports it .The 
> overlap between the tubing and the 4x4 is about eight inches as well . I 
> was doing some testing today and discovered that touching the 4x4 at the 
> top caused the swr to increase from about 1.2 to 1 to 1.7 to 1 . The lower 
> on the 4x4 I touch the less the effect . I am only moving my finger a 
> fraction of an inch and my hand not at all when this happens .The feed 
> lines are disconnected when this is going on .There is no dc continuity 
> between the antenna and any mounting hardware or th
> e post .I disconnected the base loading and put  the analyzer on it and it 
> is resonant at about 8 mhz and touching the post causes no change with 
> this setup . There are eight 30 foot radials laying on the ground and a 2 
> inch wide copper strap about 3 foot long  in the hole that the 4x4 is in .
> What is going on here and should I make an effort to limit the coupling 
> between the 4x4 and the antenna?
>
>
> 73 , Glenn WW4B
> _________________
> Topband Reflector
>
>
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