[CQ-Contest] 4 Square/ Raised Radial Questions

[David Robbins K1TTT]

I wasn't talking about ground losses, I was considering the effect of adding
ferrites to the shield of the coax feeding the verticals.  Given that the
Feedpoint is raised, the radials are raised, and the feedline is raised, how
is the coax shield different than a radial from each Feedpoint back to the
center of the array?  What can the addition of ferrites to the 1/4 wave
lines do besides add losses to the currents that WILL be induced on the
shield of the coax as they try to flow back to the feedpoint of the
vertical.  


David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 

> -----Original Message-----
> From: cq-contest-bounces at contesting.com [mailto:cq-contest-
> bounces at contesting.com] On Behalf Of Tom Rauch
> Sent: Tuesday, January 29, 2008 10:44
> To: k1ttt at arrl.net; CQ-Contest at contesting.com
> Subject: Re: [CQ-Contest] 4 Square/ Raised Radial Questions
> 
> > Personally I consider the shield of the coax (connected to
> > the radials) to
> > be one of the radials so why choke it anyway?  Chokes at
> > that point just add
> > loss to the system when they try to block the current
> > induced on the shield
> > from getting back to the base of the vertical.
> 
> 
> Not true.
> 
> With a small elevated ground system any path to earth
> reduces field strength. That's etched in stone, it isn't a
> guess.
> 
> While the amount of loss varies can vary it always adds some
> loss. This is because the voltage to ground at the common
> point is not even close to zero, so current flows through
> the shield into the station or lossy earth along the coax
> and that represents lost power. It also results in noise
> egress back into the antenna from the station. It means the
> coax radiates and that almost never is a good thing.
> 
> Elevated radials are such a mess for stray RF, pattern
> distortion, bandwidth, and efficiency I would only consider
> them as a last resort. A second very good reason (one of the
> best reasons actually) to use them is if you are competing
> against me in a contest.
> 
> 73 Tom
> 
> 
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