Date: Sat, 7 Nov 2015 11:19:05 +0000
From: Chris Wilson <chris@chriswilson.tv>
Organization: Gatesgarth Developments
Message-ID: <514333482.20151107111905@chriswilson.tv>
To: Mike Dennison <rsgb_lf_group@blacksheep.org>
In-Reply-To: <563DD93A.22662.37C4EA@mike.dennison.ntlworld.com>
References: <1843908200.20151104162925@chriswilson.tv>, <CAA8k23QB1RxnKaYXrYq0YVscvzEsNstciTwTkW=D6Dvt2fLUYQ@mail.gmail.com>, <8E31BC8EB75546E59F99E35AFAAA0DEE@AGB> <563DD93A.22662.37C4EA@mike.dennison.ntlworld.com>
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Subject: Re[2]: LF: Capacitive top hat question
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Hello Mike,

Saturday, November 7, 2015


Thanks for the info Mike, as always! Is there any real benefit in
having the vertical section centralised within the top hat capacitive
array, be it a horizontal loop, random horizontal wires, or a plain
single wire?

And is there much point in struggling to get one corner or side of a
horizontal top hat loop higher than the rest, or the same for a single
wire? I have some tall trees, but unfortunately not two tall trees
opposite one another across free space, so whatever capacitive hat I
fix up is likely to be significantly higher at one end or one corner.
There's no point in struggling and risking life and limb to get one
end as high as possible if it ends up only as efficient as the lowest
end or point.


> To all intents and purposes a short (in wavelengths) vertical 
> attached to an arrangement of horizontal wires is a simple 
> (capacitively) loaded vertical. 

> The horizontal part will radiate, especially if it has a vertical 
> component rising higher than the feedpoint, but most of that 
> radiation will be cancelled by its reflection in the ground.

> Several unbelievers have tried using purely horizontal transmitting 
> antennas and have had poor results. The beauty of amateur radio is 
> that you can prove something to yourself, but it won't change the 
> laws of physics.

> Of course, every electrically small Marconi that is not in free space 
> performs in a complex way, but the result of that complexity is small 
> compared to the predominent omnidirectional radiation from the 
> vertical section. There is very little difference between various 
> arrangements of capacity hat, so long as you follow the rule to put 
> up as much wire as possible, as high as possible and covering as much 
> ground as possible.

> Mike, G3XDV
> ==========


-- 
Best regards,
 Chris                            mailto:chris@chriswilson.tv