RadioBanter - Antennas - balanced or not?

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Antennas - balanced or not?

The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax attachment.

Starting from the simplest of all situations, assume a dipole with an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still balanced?

Antennas - balanced or not?

On 8/4/2015 11:39 AM, John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax attachment.

Starting from the simplest of all situations, assume a dipole with an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still balanced?

Is *what* still balanced? The antenna hasn't changed and is still
balanced. The generator hasn't changed and is still balanced. But you
have added a wire which will load the generator and serve as an element
of the antenna changing the radiation pattern. How significantly the
pattern will change depends on the orientation of the wire and what it
connects to, if anything. There is also the issue of how much energy is
transmitted along the wire to whatever is connected to it.

--

Rick

Antennas - balanced or not?

John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax attachment.

Starting from the simplest of all situations, assume a dipole with an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still balanced?

You have to clearly define "it".

The original antenna is still balanced, but the new antenna system is not
because of the 3rd wire.

The magnitude of the imbalance depends on the length and orientation of
that third wire and can be anywhere from insignificant to major.

--
Jim Pennino

Antennas - balanced or not?

On 8/4/2015 11:31 AM, rickman wrote:
On 8/4/2015 11:39 AM, John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax attachment.

Starting from the simplest of all situations, assume a dipole with an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still
balanced?

Is *what* still balanced? The antenna hasn't changed and is still
balanced.

Well, the starting point is this:

----------0-----------

Where the 0 is the generator.

Then we attach a wire like so:

----------0.----------
|
|
|
|
|

I don't understand how the antenna has not changed.

The generator hasn't changed and is still balanced.

I do not understand how a two-terminal generator can be described as
either balanced or unbalanced.

But you
have added a wire which will load the generator and serve as an element
of the antenna changing the radiation pattern. How significantly the
pattern will change depends on the orientation of the wire and what it
connects to, if anything. There is also the issue of how much energy is
transmitted along the wire to whatever is connected to it.

Please disregard the radiation pattern in this thread.

Antennas - balanced or not?

On 8/5/2015 9:47 AM, John S wrote:
On 8/4/2015 11:31 AM, rickman wrote:
On 8/4/2015 11:39 AM, John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax attachment.

Starting from the simplest of all situations, assume a dipole with an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still
balanced?

Is *what* still balanced? The antenna hasn't changed and is still
balanced.

Well, the starting point is this:

----------0-----------

Where the 0 is the generator.

Then we attach a wire like so:

----------0.----------
|
|
|
|
|

I don't understand how the antenna has not changed.

The generator hasn't changed and is still balanced.

I do not understand how a two-terminal generator can be described as
either balanced or unbalanced.

But you
have added a wire which will load the generator and serve as an element
of the antenna changing the radiation pattern. How significantly the
pattern will change depends on the orientation of the wire and what it
connects to, if anything. There is also the issue of how much energy is
transmitted along the wire to whatever is connected to it.

Please disregard the radiation pattern in this thread.

If you consider the wire to be part of the antenna, then the antenna has
changed.

So what is your question?

--

Rick

Antennas - balanced or not?

On 8/5/2015 10:28 AM, rickman wrote:
On 8/5/2015 9:47 AM, John S wrote:
On 8/4/2015 11:31 AM, rickman wrote:
On 8/4/2015 11:39 AM, John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax attachment.

Starting from the simplest of all situations, assume a dipole with
an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still
balanced?

Is *what* still balanced? The antenna hasn't changed and is still
balanced.

Well, the starting point is this:

----------0-----------

Where the 0 is the generator.

Then we attach a wire like so:

----------0.----------
|
|
|
|
|

I don't understand how the antenna has not changed.

The generator hasn't changed and is still balanced.

I do not understand how a two-terminal generator can be described as
either balanced or unbalanced.

But you
have added a wire which will load the generator and serve as an element
of the antenna changing the radiation pattern. How significantly the
pattern will change depends on the orientation of the wire and what it
connects to, if anything. There is also the issue of how much energy is
transmitted along the wire to whatever is connected to it.

Please disregard the radiation pattern in this thread.

If you consider the wire to be part of the antenna, then the antenna has
changed.

In what way could the wire not be part of the antenna?

So what is your question?

You will find that in my OP. The question mark identifies it.

Antennas - balanced or not?

On 8/6/2015 9:48 AM, John S wrote:
On 8/5/2015 10:28 AM, rickman wrote:
On 8/5/2015 9:47 AM, John S wrote:
On 8/4/2015 11:31 AM, rickman wrote:
On 8/4/2015 11:39 AM, John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax
attachment.

Starting from the simplest of all situations, assume a dipole with
an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still
balanced?

Is *what* still balanced? The antenna hasn't changed and is still
balanced.

Well, the starting point is this:

----------0-----------

Where the 0 is the generator.

Then we attach a wire like so:

----------0.----------
|
|
|
|
|

I don't understand how the antenna has not changed.

The generator hasn't changed and is still balanced.

I do not understand how a two-terminal generator can be described as
either balanced or unbalanced.

But you
have added a wire which will load the generator and serve as an element
of the antenna changing the radiation pattern. How significantly the
pattern will change depends on the orientation of the wire and what it
connects to, if anything. There is also the issue of how much
energy is
transmitted along the wire to whatever is connected to it.

Please disregard the radiation pattern in this thread.

If you consider the wire to be part of the antenna, then the antenna has
changed.

In what way could the wire not be part of the antenna?

By your construction. You said you have an antenna and a wire. If you
meant for the wire to be part of the antenna you would have said that in
your OP.

So what is your question?

You will find that in my OP. The question mark identifies it.

"Is it still balanced?" I asked before, what is "it"?

You also said, "I do not understand how a two-terminal generator can be
described as either balanced or unbalanced."

A two terminal generator may have series resistance, for example. That
series resistance may not be evenly distributed. More resistance on one
leg than the other and it is no longer balanced. If the series
resistance is zero, then it would need a *lot* more of it on one leg
than the other. ;)

--

Rick

Antennas - balanced or not?

On 8/6/2015 9:13 AM, rickman wrote:
On 8/6/2015 9:48 AM, John S wrote:
On 8/5/2015 10:28 AM, rickman wrote:
On 8/5/2015 9:47 AM, John S wrote:
On 8/4/2015 11:31 AM, rickman wrote:
On 8/4/2015 11:39 AM, John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax
attachment.

Starting from the simplest of all situations, assume a dipole with
an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you have
one wire on one side and two wires on the other side. Is it still
balanced?

Is *what* still balanced? The antenna hasn't changed and is still
balanced.

Well, the starting point is this:

----------0-----------

Where the 0 is the generator.

Then we attach a wire like so:

----------0.----------
|
|
|
|
|

I don't understand how the antenna has not changed.

The generator hasn't changed and is still balanced.

I do not understand how a two-terminal generator can be described as
either balanced or unbalanced.

But you
have added a wire which will load the generator and serve as an
element
of the antenna changing the radiation pattern. How significantly the
pattern will change depends on the orientation of the wire and what it
connects to, if anything. There is also the issue of how much
energy is
transmitted along the wire to whatever is connected to it.

Please disregard the radiation pattern in this thread.

If you consider the wire to be part of the antenna, then the antenna has
changed.

In what way could the wire not be part of the antenna?

By your construction. You said you have an antenna and a wire. If you
meant for the wire to be part of the antenna you would have said that in
your OP.

How would YOU have stated it?

So what is your question?

You will find that in my OP. The question mark identifies it.

"Is it still balanced?" I asked before, what is "it"?

The system.

You also said, "I do not understand how a two-terminal generator can be
described as either balanced or unbalanced."

A two terminal generator may have series resistance, for example. That
series resistance may not be evenly distributed. More resistance on one
leg than the other and it is no longer balanced. If the series
resistance is zero, then it would need a *lot* more of it on one leg
than the other. ;)

But, there is a problem with your explanation. Inside the bubble (the
generator, noted as 0) you can have whatever impedance and whatever
network your heart desires. But for the two terminals exiting the
generator, the current will be the same on each terminal. It must, for
there are only two terminals. Whatever goes into one terminal, goes out
the other. In the ASCII figure model, I did not include any external
connections other than the wires.

So, what would you conclude from this?

Antennas - balanced or not?

On 8/6/2015 12:07 PM, John S wrote:
On 8/6/2015 9:13 AM, rickman wrote:
On 8/6/2015 9:48 AM, John S wrote:
On 8/5/2015 10:28 AM, rickman wrote:
On 8/5/2015 9:47 AM, John S wrote:
On 8/4/2015 11:31 AM, rickman wrote:
On 8/4/2015 11:39 AM, John S wrote:
The balun thread has become long (138 posts). I propose that we not
discuss baluns, but concentrate on antenna balance and coax
attachment.

Starting from the simplest of all situations, assume a dipole with
an RF
generator in the middle. If we can't agree that this is a balanced
system, then we have nothing left to discuss.

Connect an additional wire to one side of the source so that you
have
one wire on one side and two wires on the other side. Is it still
balanced?

Is *what* still balanced? The antenna hasn't changed and is still
balanced.

Well, the starting point is this:

----------0-----------

Where the 0 is the generator.

Then we attach a wire like so:

----------0.----------
|
|
|
|
|

I don't understand how the antenna has not changed.

The generator hasn't changed and is still balanced.

I do not understand how a two-terminal generator can be described as
either balanced or unbalanced.

But you
have added a wire which will load the generator and serve as an
element
of the antenna changing the radiation pattern. How significantly the
pattern will change depends on the orientation of the wire and
what it
connects to, if anything. There is also the issue of how much
energy is
transmitted along the wire to whatever is connected to it.

Please disregard the radiation pattern in this thread.

If you consider the wire to be part of the antenna, then the antenna
has
changed.

In what way could the wire not be part of the antenna?

By your construction. You said you have an antenna and a wire. If you
meant for the wire to be part of the antenna you would have said that in
your OP.

How would YOU have stated it?

I'm not sure what you are asking. I don't want to get into a pedantic
thing. Let's just iron out the misunderstanding and move forward.

Do you intend for the wire to be part of the antenna? Is the wire
connected to ground or just hanging in space?

So what is your question?

You will find that in my OP. The question mark identifies it.

"Is it still balanced?" I asked before, what is "it"?

The system.

I don't know what the definition of a balanced system is. But I would
think it was pretty obvious that this is not balanced by nearly any
definition.

You also said, "I do not understand how a two-terminal generator can be
described as either balanced or unbalanced."

A two terminal generator may have series resistance, for example. That
series resistance may not be evenly distributed. More resistance on one
leg than the other and it is no longer balanced. If the series
resistance is zero, then it would need a *lot* more of it on one leg
than the other. ;)

But, there is a problem with your explanation. Inside the bubble (the
generator, noted as 0) you can have whatever impedance and whatever
network your heart desires. But for the two terminals exiting the
generator, the current will be the same on each terminal. It must, for
there are only two terminals. Whatever goes into one terminal, goes out
the other. In the ASCII figure model, I did not include any external
connections other than the wires.

So, what would you conclude from this?

Does equal current imply "balanced"? What about the voltage? But then
I am thinking relative to ground and your generator has no ground.
Still, the voltage at the two points do not have to be equal but
opposite. The point is the impact it will have on the antenna.

Look at what a balun does. On both sides of the balun, the current
going in and out each wire are equal, but obviously one side of the
balun is considered balanced and the other not. So equal current does
not imply "balanced".

--

Rick