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From: liz@poppyrecords.invalid.invalid (Liz Tuddenham)
Newsgroups: sci.electronics.design
Subject: Re: Sleeve dipoles
Date: Mon, 23 Dec 2024 21:30:42 +0000
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Ralph Mowery <rmowery42@charter.net> wrote:

> In article <1r5178a.10eyjis13gf62kN%liz@poppyrecords.invalid.invalid>,
> liz@poppyrecords.invalid.invalid says...
> > 
> > > The bottom  dipole half is never grounded. Another name is coaxial
> > >  antenna. Usually you find them in marine application because of
> > >  the counter poise. 
> > 
> > Suppose the feed point had a 1:1 isolation transformer, there would be
> > no reason why the dipole couldn't be grounded at any point alog its
> > length.  The same isolatio could be achieved by a quarter-wave line.
> > 
> > 
> > 
> 
> The bottom half can not be grounded no matter what except at the feed
> point maybe. 

I think you may have misunderstood the point I was trying to make.
Suppose, for instance, you drove the dipole from a battery-powered
transistor oscillator physically located at the centre point,  there is
no reason why the bottom of the dipole could not be grounded and the
oscillator left to 'float' at about half potential.

In that case, driving the dipole from an isolation transformer would
have the same effect (if we neglect the inter-winding capacitance of a
practical transformer).

-- 
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk