Dave,
There is a big difference between the current flowing on
the inside of the shield of coax and any current flowing on
the outside of the shield. The current flowing on the inside
of the coax shield is the same current that flows in the
center conductor (not the same polarity/phase). Ideally, there
will be no current flowing on the outside of the coax shield,
but you very seldom ever run across the 'ideal' situation. The
current flowing on the outside of the shield is what makes the
feed line radiate.
'Doc

"'Doc" wrote in message ...


Dave,
There is a big difference between the current flowing on
the inside of the shield of coax and any current flowing on
the outside of the shield. The current flowing on the inside
of the coax shield is the same current that flows in the
center conductor (not the same polarity/phase). Ideally, there
will be no current flowing on the outside of the coax shield,
but you very seldom ever run across the 'ideal' situation. The
current flowing on the outside of the shield is what makes the
feed line radiate.
'Doc

exactly.

Dave,
And the idea of 'half' of a dipole as being a 'passive'
element. In which half of a signal's cycle is the shield
side of the dipole passive? The 'positive' or 'negative'
half cycle? And since current is still moving in the
'passive' half of the antenna, it's also still being
radiated. How does that fit in with your 'passive' element
description? If it radiates, it ain't 'passive'.
I can follow your thinking, but your thinking will lead
you into making very confusing statements as you've done.
Why not stick to the 'standard' or common way of describing
what you mean? It'll save a lot of confusion and bandwidth.
'Doc

How does that fit in with your 'passive' element
description? If it radiates, it ain't 'passive'.

the passive elements on a yagi have current flow in them, and they are
indeed passive elements.
passive dosen't mean 'no current flow' in this context, it means not driven
from the feedline.

I can follow your thinking, but your thinking will lead
you into making very confusing statements as you've done.
Why not stick to the 'standard' or common way of describing
what you mean? It'll save a lot of confusion and bandwidth.
'Doc

i didn't coin the term 'passive element'

Dave,
----snipped--------
passive dosen't mean 'no current flow' in this context, it means not driven
from the feedline.


And the 'passive' element of a dipole antenna ~isn't~ fed
from the feed line? Confusing'er and confusing'er. I thought
both 'halves' of a dipole were fed by the feed line, certainly
every one that I've made, or seen have been.

----snipped---------

i didn't coin the term 'passive element'

No, I'm aware of that. But are you the one who 'minted' the
"two signal" way of looking at a single signal? Like some other
types of esoteric thinking you have to be very careful where
they
are applied, and how. If you aren't careful, they deteriorate
into nonsense as has happened here. If how you think about a
dipole antenna helps you with what you're doing, then fine, have
at it. That doesn't make it 'correct' or the 'right' way of
doing
things, though, and it is very confusing to someone who isn't
familiar with that particular 'theory' of operation. If you
want to
call a dipole by another name, that's fine too. But it don't
make
it so. Aunt Martha wasn't born with wheels, so she really isn't
a Buick... no matter what she thinks.
'Doc

"'Doc" wrote in message ...


Dave,
----snipped--------
passive dosen't mean 'no current flow' in this context, it means not
driven
from the feedline.


And the 'passive' element of a dipole antenna ~isn't~ fed
from the feed line? Confusing'er and confusing'er.

i've been maintaining that a properly implemented dipole does not have a
passive element.
both halves should be driven. in the case where it's fed directly with
coax, it isn't clear to me wether the shield connected element is getting
current from the inside of the shield, or by illumination from the center
connected element. i suspect both are true, to some degree.
certainly the rf on the feedline now couples into the system, and makes
things even fuzzier.

I thought both 'halves' of a dipole were fed by the feed line, certainly
every one that I've made, or seen have been.

No, I'm aware of that. But are you the one who 'minted' the
"two signal" way of looking at a single signal? Like some other
types of esoteric thinking you have to be very careful where
they
are applied, and how.

i wasn't as clear as i intended to be.
you can view the output of a balun as two out of phase signals, at half the
input power, or a single balanced signal. i wasn't sure if the fellow i was
talking to at that point, knew what you get at the output of a balun.

If you aren't careful, they deteriorate
into nonsense as has happened here. If how you think about a
dipole antenna helps you with what you're doing, then fine, have
at it. That doesn't make it 'correct' or the 'right' way of
doing
things, though, and it is very confusing to someone who isn't
familiar with that particular 'theory' of operation. If you
want to
call a dipole by another name, that's fine too. But it don't
make
it so.

no, the point i was making is that a dipole, is designed to be fed from a
balanced source, and it does make a difference. the magnitude of the
difference, in gain, radiation, and rf on the feedline /when feeding it
unbalanced/ is debatable.

Aunt Martha wasn't born with wheels, so she really isn't
a Buick... no matter what she thinks.
'Doc

beep beep /vbg/

On Tue, 16 Sep 2003 16:19:28 -0500, "Dave VanHorn"
wrote:

i wasn't as clear as i intended to be.
you can view the output of a balun as two out of phase signals, at half the
input power, or a single balanced signal. i wasn't sure if the fellow i was
talking to at that point, knew what you get at the output of a balun.

Yeah, that was that Dave Vanhorn fellow you were talking to. I don't
think he quite understands what a balun is or what it does.

In , "Dave VanHorn"
wrote:

snip
no, the point i was making is that a dipole, is designed to be fed from a
balanced source, and it does make a difference.

If you are saying that a balanced load should be fed from a balanced source,
I'll buy that. But don't forget that a dipole doesn't necessarily need to be
balanced. It's just as easy, if not easier, to shift the feedpoint (gamma match)
as it is to wind a balun.

the magnitude of the
difference, in gain, radiation, and rf on the feedline /when feeding it
unbalanced/ is debatable.

I dunno... I've pegged my FSM more than a few times holding it next to a coax.
But that may not be such a bad thing if you want some vertical polarity while
using a horizontal dipole.





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