"Wayne" napisal w wiadomosci
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"Szczepan Bialek" wrote in message
.. .


"Wayne" napisal w wiadomosci
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"Szczepan Bialek" wrote in message
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On Friday, April 26, 2013 12:38:06 PM UTC-5, Irv Finkleman wrote:
snip

Maybe SB can explain the difference between a monopole with a single
ungrounded radial, and a dipole.

Each radial, grounded or not (but connected to the shield of the coax),
is the ground.
The Earth, the Moon, a satelite and each piece of conductor is ground
for antennas. Radial is one of them.
Ground must be adequate to kW.

What if the single ungrounded quarter wave radial is in line with the
quarter wave radiator?
Is it still a monopole?

# Of course.

Wow...you gave a lot to digest.

Just to understand the discussion, let's address the monopole with one
radial.

Assuming the monopole is 1/4 wave long, and has a 1/4 wave long radial.
The radial is in line with the monopole. Everything is ungrounded.

# The radial connected with the shield of the coax is the ground.


How does that configuration of a monopole with one radial differ from a
dipole?

The true horizontal dipole (electrically symmetric) radiate in one direction
only. A monopole in all directions.

So a half wave wire broken at the center is a monopole with a single
radial if it is fed directly with coax?

Yes. The one leg is the radiator and the second is a ground (like a
satellite chassis).

And it is a dipole if it has a balanced feed?

The true dipole is electrically symmetric. The same voltages but in the
opposite phase.
Thank this the interference take place and a dipole has the main lobe and
many side lobes.
With the monopole no lobes.

What if the coax feedline has a quarter wave sleeve, open at the antenna
but connected to the coax at the other end?
Is it a monopole or a dipole?

"Marconi, who discovered if he attached one terminal of his transmitter to a
wire suspended in the air and the other to the Earth, he could transmit for
longer distances".

As you know are many version of ground because the soil is not the best.
The sleeve, the braid of the coax and so on are only the better ground.

Dipole must be electrically symmetric.
If one leg is connected to the any version of ground such "dipole" radiate
as monopole.
S*