[TowerTalk] Vertical Antenna Close to Fresh Water

[John Geiger]

The most recent issue of National Contest Journal ran an article about verticals and ground losses.  It found that even with 120 radials, ground losses are fairly significant on 40m and below, at least.  They didn't do any tests above 40 meters.  The only way to prevent ground losses was to run the vertical right next to a body of salt water.

73s John AA5JG

--- On Thu, 11/12/09, Roger Parsons <ve3zi at yahoo.com> wrote:

> From: Roger Parsons <ve3zi at yahoo.com>
> Subject: [TowerTalk] Vertical Antenna Close to Fresh Water
> To: towertalk at contesting.com
> Date: Thursday, November 12, 2009, 1:27 PM
> There was a short discussion a while
> ago on whether a vertical was better ground mounted fed
> against ground radials or up in the air fed against resonant
> radials. The general consensus was that 'up in the air' was
> better - but that is directly contrary to my experience.
> 
> The only thing different about my situation is that I have
> several verticals very close to the edge of a large fresh
> water lake. They work better than similar verticals several
> hundred feet from the lake, and better than verticals up in
> the air.
> 
> Conventional wisdom has it that as the conductivity of
> fresh water is quite low, it should make no difference at
> all - but it seems that in my case it does. I have a couple
> of hypotheses and would welcome comments:
> 
> (1) The soil in this area is pretty poor with rock a foot
> or two below the surface everywhere. Anything must be better
> than that - but surely a large ground system would negate
> that.
> 
> (2) The surface of the lake is pretty flat (:-) so that
> there is a good first reflection - better than that from
> rocks and trees. ('My' lake is north of my property, and as
> I am on a bit of a promontory covers rather more than 180
> degrees.)
> 
> Any thoughts?
> 
> 73 Roger
> VE3ZI
> 
> 
> 
>       
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