"John S" wrote in message ...

On 7/28/2015 11:57 AM, John S wrote:
On 7/27/2015 3:45 PM, Wayne wrote:
Just today I got a question from a new ham on the pronunciation of balun.

He has been around the scientific community a lot (physicists, etc.) but
not many RF types such as engineers or hams.

He claims that he rarely has ever hear the pronunciation "bal uhn", and
I've rarely heard "bayl uhn".

Anybody want to weigh in on this, heh heh


Hey, Wayne -

Do you have or want EZNEC? There is a free (limited) version.

Just curious.

Sorry, folks. I meant to post this in another thread.

But to go ahead with an answer...
Thanks. I have version 3.0, and it does the job for me.

I got my first copy back in the days when W7EL frequented this group and
knew by call sign who had legal copies

On Tue, 28 Jul 2015 10:58:28 -0700, "Wayne"
wrote:

But to go ahead with an answer...
Thanks. I have version 3.0, and it does the job for me.

I got my first copy back in the days when W7EL frequented this group and
knew by call sign who had legal copies

You might want to try 4NEC2:
http://www.qsl.net/4nec2/
Showing off... some of my results (not all original):
http://802.11junk.com/jeffl/antennas/
Mo
https://www.google.com/search?tbm=isch&q=4nec2+antenna+models

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...

On Tue, 28 Jul 2015 10:58:28 -0700, "Wayne"
wrote:

But to go ahead with an answer...
Thanks. I have version 3.0, and it does the job for me.

I got my first copy back in the days when W7EL frequented this group and
knew by call sign who had legal copies

You might want to try 4NEC2:
http://www.qsl.net/4nec2/
Showing off... some of my results (not all original):
http://802.11junk.com/jeffl/antennas/
Mo
https://www.google.com/search?tbm=isch&q=4nec2+antenna+models
*****************

Looks good. I'll give it a try.

On 7/28/2015 12:58 PM, Wayne wrote:

"John S" wrote in message ...

Hey, Wayne -

Do you have or want EZNEC? There is a free (limited) version.

Just curious.

Thanks. I have version 3.0, and it does the job for me.

I got my first copy back in the days when W7EL frequented this group and
knew by call sign who had legal copies

The hidden reason I asked the question is that I think you should model
some antennas and look at the current on the shield of the transmission
line. I have done this, and I don't see major problems if the system
remains balanced just as lore suggests.

This brings up a question of my own. By changing the slope of the coax
shield, I can get increased current in it. The question is, at what
point does it become a problem? As far as the antenna pattern is
concerned, I would not worry. RF in the shack is another matter. In
about 1958, my lips got some RF when they touched the D104 mike. Didn't
hurt me, but I didn't like it. At the time I had no understanding of
this phenomenon.

Anyway, it would be nice if we could decide, measure, or simulate how
much feed line current should be allowed. Maybe the answer is to
simulate how much voltage appears in the shack.

Lots of questions. A large area for investigation.

"John S" wrote in message ...

On 7/28/2015 12:58 PM, Wayne wrote:

"John S" wrote in message ...

Hey, Wayne -

Do you have or want EZNEC? There is a free (limited) version.

Just curious.

Thanks. I have version 3.0, and it does the job for me.

I got my first copy back in the days when W7EL frequented this group and
knew by call sign who had legal copies

The hidden reason I asked the question is that I think you should model
some antennas and look at the current on the shield of the transmission
line. I have done this, and I don't see major problems if the system
remains balanced just as lore suggests.

This brings up a question of my own. By changing the slope of the coax
shield, I can get increased current in it. The question is, at what point
does it become a problem? As far as the antenna pattern is concerned, I
would not worry. RF in the shack is another matter. In about 1958, my lips
got some RF when they touched the D104 mike. Didn't hurt me, but I didn't
like it. At the time I had no understanding of this phenomenon.

Anyway, it would be nice if we could decide, measure, or simulate how much
feed line current should be allowed. Maybe the answer is to simulate how
much voltage appears in the shack.

Lots of questions. A large area for investigation.

The reason for my balun question (other than to generate meaningful
technical banter on the newsgroup) is that some years ago in the age of
sliderules, a widely known and respected antenna guru told me that a balun
was unnecessary at resonance ( j=0 ).

I lost touch with him and don't know if his views changed over the years.

On 7/29/2015 11:56 AM, Wayne wrote:


"John S" wrote in message ...

On 7/28/2015 12:58 PM, Wayne wrote:

"John S" wrote in message ...

Hey, Wayne -

Do you have or want EZNEC? There is a free (limited) version.

Just curious.

Thanks. I have version 3.0, and it does the job for me.

I got my first copy back in the days when W7EL frequented this group and
knew by call sign who had legal copies

The hidden reason I asked the question is that I think you should
model some antennas and look at the current on the shield of the
transmission line. I have done this, and I don't see major problems if
the system remains balanced just as lore suggests.

This brings up a question of my own. By changing the slope of the coax
shield, I can get increased current in it. The question is, at what
point does it become a problem? As far as the antenna pattern is
concerned, I would not worry. RF in the shack is another matter. In
about 1958, my lips got some RF when they touched the D104 mike.
Didn't hurt me, but I didn't like it. At the time I had no
understanding of this phenomenon.

Anyway, it would be nice if we could decide, measure, or simulate how
much feed line current should be allowed. Maybe the answer is to
simulate how much voltage appears in the shack.

Lots of questions. A large area for investigation.

The reason for my balun question (other than to generate meaningful
technical banter on the newsgroup) is that some years ago in the age of
sliderules, a widely known and respected antenna guru told me that a
balun was unnecessary at resonance ( j=0 ).

I lost touch with him and don't know if his views changed over the years.

I disagree with him.

Please see Roy Lewallen's (W7EL, author of EZNEC) site for some good
reading. He is a superb writer of easy to understand technical tidbits.
He has some balun stuff among other stuff.

http://eznec.com/misc/

On 7/29/2015 1:42 PM, John S wrote:
On 7/29/2015 11:56 AM, Wayne wrote:

Lots of questions. A large area for investigation.

The reason for my balun question (other than to generate meaningful
technical banter on the newsgroup) is that some years ago in the age of
sliderules, a widely known and respected antenna guru told me that a
balun was unnecessary at resonance ( j=0 ).

I lost touch with him and don't know if his views changed over the years.

I disagree with him.

Please see Roy Lewallen's (W7EL, author of EZNEC) site for some good
reading. He is a superb writer of easy to understand technical tidbits.
He has some balun stuff among other stuff.

http://eznec.com/misc/

Perhaps someone can explain the issue of current in the coax shield.
Current gives rise to a magnetic field. But the current in the inner
conductor is opposite and would create a magnetic field that would
cancel the field of the outer conductor, no?

What am I missing?

--

Rick

On 7/29/2015 1:16 PM, rickman wrote:
On 7/29/2015 1:42 PM, John S wrote:
On 7/29/2015 11:56 AM, Wayne wrote:

Lots of questions. A large area for investigation.

The reason for my balun question (other than to generate meaningful
technical banter on the newsgroup) is that some years ago in the age of
sliderules, a widely known and respected antenna guru told me that a
balun was unnecessary at resonance ( j=0 ).

I lost touch with him and don't know if his views changed over the
years.

I disagree with him.

Please see Roy Lewallen's (W7EL, author of EZNEC) site for some good
reading. He is a superb writer of easy to understand technical tidbits.
He has some balun stuff among other stuff.

http://eznec.com/misc/

Perhaps someone can explain the issue of current in the coax shield.
Current gives rise to a magnetic field. But the current in the inner
conductor is opposite and would create a magnetic field that would
cancel the field of the outer conductor, no?

What am I missing?


Skin effect. The currents on the inside of the shield and on the outside
of the shield see different things. They each have no idea what the
other is doing.

As for magnetic field, I must step aside. I can only report what the
gurus say (nothing that I've found).

On 7/29/2015 2:32 PM, John S wrote:
On 7/29/2015 1:16 PM, rickman wrote:
On 7/29/2015 1:42 PM, John S wrote:
On 7/29/2015 11:56 AM, Wayne wrote:

Lots of questions. A large area for investigation.

The reason for my balun question (other than to generate meaningful
technical banter on the newsgroup) is that some years ago in the age of
sliderules, a widely known and respected antenna guru told me that a
balun was unnecessary at resonance ( j=0 ).

I lost touch with him and don't know if his views changed over the
years.

I disagree with him.

Please see Roy Lewallen's (W7EL, author of EZNEC) site for some good
reading. He is a superb writer of easy to understand technical tidbits.
He has some balun stuff among other stuff.

http://eznec.com/misc/

Perhaps someone can explain the issue of current in the coax shield.
Current gives rise to a magnetic field. But the current in the inner
conductor is opposite and would create a magnetic field that would
cancel the field of the outer conductor, no?

What am I missing?


Skin effect. The currents on the inside of the shield and on the outside
of the shield see different things. They each have no idea what the
other is doing.

As for magnetic field, I must step aside. I can only report what the
gurus say (nothing that I've found).

I don't follow what skin effect has to do with the issue. The current
flowing on the outside of the shield is the only current flowing in the
shield. What's your point?

--

Rick

In message , John S
writes
On 7/29/2015 1:16 PM, rickman wrote:
On 7/29/2015 1:42 PM, John S wrote:
On 7/29/2015 11:56 AM, Wayne wrote:

Lots of questions. A large area for investigation.

The reason for my balun question (other than to generate meaningful
technical banter on the newsgroup) is that some years ago in the age of
sliderules, a widely known and respected antenna guru told me that a
balun was unnecessary at resonance ( j=0 ).

I lost touch with him and don't know if his views changed over the
years.

I disagree with him.

Please see Roy Lewallen's (W7EL, author of EZNEC) site for some good
reading. He is a superb writer of easy to understand technical tidbits.
He has some balun stuff among other stuff.

http://eznec.com/misc/

Perhaps someone can explain the issue of current in the coax shield.
Current gives rise to a magnetic field. But the current in the inner
conductor is opposite and would create a magnetic field that would
cancel the field of the outer conductor, no?

What am I missing?


Skin effect. The currents on the inside of the shield and on the
outside of the shield see different things. They each have no idea what
the other is doing.

As for magnetic field, I must step aside. I can only report what the
gurus say (nothing that I've found).

Even though the coax shield is grounded at the shack end, both halves of
the antenna get fed push-pull (in anti-phase) with the RF signal flowing
on the outer skin of the inner conductor and the inner skin of the
shield.

However, at the antenna end, the returning RF on the shield side of the
antenna doesn't know that it should stay on the inside of the shield.
Because of the skin effect, it happily makes for the outside, whence it
flows back to shack, and through the shack grounding connections.

If the shack ground connections are not very short - or imperfect - the
supposedly grounded equipment is hot RF-wise. Furthermore, on
transmission the shield outer current radiates, and if it is in close
proximity to any susceptible domestic equipment, it can cause
interference problems to it. And because things will be reciprocal on
receive, the shield won't act too well as a shield to nasty RF
interference being emitted my nearby domestic equipment.
--
Ian