[TowerTalk] Modeling

Al Williams alwilliams@olywa.net
Mon, 4 Feb 2002 21:08:30 -0800



----- Original Message ----- 
From: <n4kg@juno.com>
To: <TOWERTALK@contesting.com>
Sent: Monday, February 04, 2002 9:24 PM
Subject: Re: [TowerTalk] Modeling


> 
> There is a reason that 12M Yagi's interact with
> tribanders and 10 and / or 15 meter beams...
What is the mechanism that causes an element longer than the driven
element to re-radiate in the same direction as an element shorter
than the driven element but on the opposite side?

Please, answer not too heavy in math, physics, and geometry but also
not simplistic.

k7puc

 
> 
> 12M self resonant elements are only 14% longer 
> than 10M self resonant elements and 12M Directors 
> are ~9% longer than a 10M DE so they make fairly good 
> REFLECTORS to the 10M Driven Element
> 
> 12M self resonant elements are only 18% shorter 
> than 15M self resonant elements and 12M reflectors
> are ~13% shorter than a 15M DE so they can act as 
> short DIRECTORS to a 15M Driven Element.
> 
> When they are placed only 6 ft from a tribander,
> the are CLOSELY  COUPLED  to the tribander,
> being only 0.125WL away on 15M and 0.166 WL
> away on 10M, i.e. your typical Yagi element spacing.
> 
> Tom  N4KG



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