3-phase antenna.
 

There is a 3-phase transmitter feeding a 3-phase antenna via a 3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.

Reg Edwards wrote:
There is a 3-phase transmitter feeding a 3-phase antenna via a 3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.

Hi Reg, Is the 3-phase transmitter balanced with the output current
equal magnitude, and the phase angle exactly 120 degrees? Is the
3-phase antenna fed via a 3-wire transmission line, or three equal
length transmission lines? Us Amateurs don't have a lot of experience
with 3-wire coax. Are the horizontal radiators 1/4-wave, or 1/2 wave?
If they are 1/4 wave, or 1/2 wave and spaced 120 degrees in the
horizontal plane, doesn't that form an equilateral triangle? So, you
are feeding a triangular antenna whose sides are 1/4-wave in the centre
of each side with balanced 3-phase rf energy?
Even if you clarify this is I still won't know the answer to your
question until I model the array.
Gary N4AST

wrote in message
oups.com...

Reg Edwards wrote:
There is a 3-phase transmitter feeding a 3-phase antenna via a
3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced
at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.

Hi Reg, Is the 3-phase transmitter balanced with the output
current
equal magnitude, and the phase angle exactly 120 degrees? Is the
3-phase antenna fed via a 3-wire transmission line, or three equal
length transmission lines? Us Amateurs don't have a lot of
experience
with 3-wire coax. Are the horizontal radiators 1/4-wave, or 1/2
wave?
If they are 1/4 wave, or 1/2 wave and spaced 120 degrees in the
horizontal plane, doesn't that form an equilateral triangle? So,
you
are feeding a triangular antenna whose sides are 1/4-wave in the
centre
of each side with balanced 3-phase rf energy?
Even if you clarify this is I still won't know the answer to your
question until I model the array.
Gary N4AST
=======================================

The three antenna wires are like the spokes of a wheel, spaced at 120
degrees, and each 1/4-wave in length. All in the horizontal plane.

The transmission line is balanced about ground and each of the line
wires is connected to one of the three antenna elements at the center
of the wheel. There's no need to pull the line wires apart at the end
of the line.

What is the radiation pattern in the horizontal plane?

Also what is the equivalent load impedance between each of the line
wires.
----
Reg.

Reg Edwards wrote:
wrote in message
oups.com...

Reg Edwards wrote:
There is a 3-phase transmitter feeding a 3-phase antenna via a
3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced
at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.

Hi Reg, Is the 3-phase transmitter balanced with the output
current
equal magnitude, and the phase angle exactly 120 degrees? Is the
3-phase antenna fed via a 3-wire transmission line, or three equal
length transmission lines? Us Amateurs don't have a lot of
experience
with 3-wire coax. Are the horizontal radiators 1/4-wave, or 1/2
wave?
If they are 1/4 wave, or 1/2 wave and spaced 120 degrees in the
horizontal plane, doesn't that form an equilateral triangle? So,
you
are feeding a triangular antenna whose sides are 1/4-wave in the
centre
of each side with balanced 3-phase rf energy?
Even if you clarify this is I still won't know the answer to your
question until I model the array.
Gary N4AST
=======================================

The three antenna wires are like the spokes of a wheel, spaced at 120
degrees, and each 1/4-wave in length. All in the horizontal plane.

The transmission line is balanced about ground and each of the line
wires is connected to one of the three antenna elements at the center
of the wheel. There's no need to pull the line wires apart at the end
of the line.

What is the radiation pattern in the horizontal plane?

Also what is the equivalent load impedance between each of the line
wires.
----
Reg.
Ok, I was thinking in terms of a Delta configuration, and you were
thinking of a Star Configuration. Need more time. Did you consider a
Delta (triangle) configuration when you thought this up?
Gary N4AST

I am not sure, but I have been wondering for years.
Seriously

It's the old question: How do you load three guy wires?
73
H.


"Reg Edwards" wrote in message
...
There is a 3-phase transmitter feeding a 3-phase antenna via a 3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.

wrote in message
oups.com...

Reg Edwards wrote:
wrote in message
oups.com...

Reg Edwards wrote:
There is a 3-phase transmitter feeding a 3-phase antenna via a
3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced
at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.

Hi Reg, Is the 3-phase transmitter balanced with the output
current
equal magnitude, and the phase angle exactly 120 degrees? Is the
3-phase antenna fed via a 3-wire transmission line, or three equal
length transmission lines? Us Amateurs don't have a lot of
experience
with 3-wire coax. Are the horizontal radiators 1/4-wave, or 1/2
wave?
If they are 1/4 wave, or 1/2 wave and spaced 120 degrees in the
horizontal plane, doesn't that form an equilateral triangle? So,
you
are feeding a triangular antenna whose sides are 1/4-wave in the
centre
of each side with balanced 3-phase rf energy?
Even if you clarify this is I still won't know the answer to your
question until I model the array.
Gary N4AST
=======================================

The three antenna wires are like the spokes of a wheel, spaced at 120
degrees, and each 1/4-wave in length. All in the horizontal plane.

The transmission line is balanced about ground and each of the line
wires is connected to one of the three antenna elements at the center
of the wheel. There's no need to pull the line wires apart at the end
of the line.

What is the radiation pattern in the horizontal plane?

Also what is the equivalent load impedance between each of the line
wires.
----
Reg.
Ok, I was thinking in terms of a Delta configuration, and you were
thinking of a Star Configuration. Need more time. Did you consider a
Delta (triangle) configuration when you thought this up?
Gary N4AST

Actually, I think it is delta connected. A Y connection would Imply half
wave dipoles with their feedpoints connected between each of the three wires
and the neutral point. I am holding my breath for the answer.

Tam/WB2TT

Reg:

I do understand this correctly, and each antenna is fed a signal 120
degrees out of electrical phase with the other 2. And, the physical
placement of the also happens so as to place any specific one of the three
antennas 120 degrees ahead/behind the other two in a physical circle?

John

On Fri, 19 Aug 2005 20:21:38 +0000, Reg Edwards wrote:

There is a 3-phase transmitter feeding a 3-phase antenna via a 3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.

"John Smith" wrote in message
...
Reg:

I do understand this correctly, and each antenna is fed a signal 120
degrees out of electrical phase with the other 2. And, the physical
placement of the also happens so as to place any specific one of the three
antennas 120 degrees ahead/behind the other two in a physical circle?

John

Are these antennas fed with coax?

Frank

Frank:

Let's hope Reg will enlighten us on the exact specifics... I am afraid it
his "word problem" and he says what is and what is not...

John

On Sat, 20 Aug 2005 02:34:35 +0000, Frank wrote:


"John Smith" wrote in message
...
Reg:

I do understand this correctly, and each antenna is fed a signal 120
degrees out of electrical phase with the other 2. And, the physical
placement of the also happens so as to place any specific one of the three
antennas 120 degrees ahead/behind the other two in a physical circle?

John

Are these antennas fed with coax?

Frank

Just a hint:
Think of how a turnstile antenna works. That one works in the
horizontal plane with 90 degree phasing. Check the radiation patern.


Reg Edwards wrote:
There is a 3-phase transmitter feeding a 3-phase antenna via a 3-wire
transmission line.

The antenna consists of three 1/4-wave horizontal radiators spaced at
120 degee intervals.

Is the radiation pattern in the horizontal plane perfectly
omni-directional?
----
Reg.