Although the formulae did not copy properly, if one wants to help me with
this, they can go to the link below for the proper fomatting of these
formulae. I would really appreciate it.

Thank you.

j/b


d= .0808 (12 gauge stranded copper)
S= 6 inches
r=Effective dielectric constant (Air = 1.00054)


Here is the Wikipedia link for these formulae:
http://unblockmoney.info/browse.php?...xhZGRlcl9saW5l

The formula to calculate the impedance of ladder line is:





The formula to calculate the impedance of open (air dielectric) ladder line
is:



The formula to calculate the distance between conductors of open ladder line
is:



Whe
Z0 = Impedance.
S = Center to center distance between wires.
d = Diameter of the wire.
r = Effective dielectric constant (Air = 1.00054).
The unit of measure for S and d are not critical as long as they are the
same.

I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

ANYONE?

"justme" wrote in message
...
Although the formulae did not copy properly, if one wants to help me with
this, they can go to the link below for the proper fomatting of these
formulae. I would really appreciate it.

Thank you.

j/b


d= .0808 (12 gauge stranded copper)
S= 6 inches
r=Effective dielectric constant (Air = 1.00054)


Here is the Wikipedia link for these formulae:
http://unblockmoney.info/browse.php?...xhZGRlcl9saW5l

The formula to calculate the impedance of ladder line is:





The formula to calculate the impedance of open (air dielectric) ladder
line
is:



The formula to calculate the distance between conductors of open ladder
line
is:



Whe
Z0 = Impedance.
S = Center to center distance between wires.
d = Diameter of the wire.
r = Effective dielectric constant (Air = 1.00054).
The unit of measure for S and d are not critical as long as they are the
same.

I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

On Thu, 24 Sep 2009 14:57:20 -0500, justme wrote:

ANYONE?

"justme" wrote in message
...
Although the formulae did not copy properly, if one wants to help me with
this, they can go to the link below for the proper fomatting of these
formulae. I would really appreciate it.


You might try one of the electronics NG's.

Good Luck!
Rich

On Thu, 24 Sep 2009 13:08:47 -0700, Rich Grise wrote:

On Thu, 24 Sep 2009 14:57:20 -0500, justme wrote:

ANYONE?

"justme" wrote in message
...
Although the formulae did not copy properly, if one wants to help me with
this, they can go to the link below for the proper fomatting of these
formulae. I would really appreciate it.


You might try one of the electronics NG's.
Or rec.radio.amateur.antenna .

Good Luck!
Rich

On Sep 23, 11:03*pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

Tim N3QE

I know that Tim however when I worked the formula, it did not compare with
ARRL's published graph and I want to know which of us is in error.

I have posted same request to the 'antenna' group.

Thanks, Tim.

j/b

"Tim Shoppa" wrote in message
...
On Sep 23, 11:03 pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

Tim N3QE

On Thu, 24 Sep 2009 13:22:16 -0700 (PDT), Tim Shoppa
wrote:

On Sep 23, 11:03*pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

Tim N3QE

VSWR isn't important anymore??


Mark Rand
RTFM

On Sat, 26 Sep 2009 01:18:19 +0100, Mark Rand
wrote:

On Thu, 24 Sep 2009 13:22:16 -0700 (PDT), Tim Shoppa
wrote:

On Sep 23, 11:03*pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

Tim N3QE

VSWR isn't important anymore??

Obviously not, just look at cell phones. The VSWR has to
really suck on them with all the crazy positions/places
people try using them. Solution, add more towers so people
don't notice it.

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

"Leon Fisk" wrote in message
...
On Sat, 26 Sep 2009 01:18:19 +0100, Mark Rand
wrote:

On Thu, 24 Sep 2009 13:22:16 -0700 (PDT), Tim Shoppa
wrote:

On Sep 23, 11:03 pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

Tim N3QE

VSWR isn't important anymore??

Obviously not, just look at cell phones. The VSWR has to
really suck on them with all the crazy positions/places
people try using them. Solution, add more towers so people
don't notice it.

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

What Justme said has been common knowledge to ham radio operators for more
than half a century. SWR doesn't matter much with ladder line, partly
because of its low loss and partly because most of the antennas it's usually
feeding are no great shakes themselves, and radiation from the transmission
line is tolerable. I switched from a balun-type coax-fed dipole to a
ladder-line-fed folded dipole once, both of them in the exact same position,
and I got much better reports on the one fed with (300 ohm) ladder line. And
I'm sure that the SWR on that line was out of whack.

As for the characteristics of microwave-frequency cell phones, I wouldn't
jump to conclusions about them. They may be so broadly tuned that SWR
doesn't change much. And things that happen up at those frequencies can be
hard to relate to what most of us know about antennas and transmission
lines. 'Dunno, I've never looked into what happens at the gigahertz realm.

--
Ed Huntress
KC2NZT

On Sat, 26 Sep 2009 14:44:31 -0400, "Ed Huntress"
wrote:



What Justme said has been common knowledge to ham radio operators for more
than half a century. SWR doesn't matter much with ladder line, partly
because of its low loss and partly because most of the antennas it's usually
feeding are no great shakes themselves, and radiation from the transmission
line is tolerable. I switched from a balun-type coax-fed dipole to a
ladder-line-fed folded dipole once, both of them in the exact same position,
and I got much better reports on the one fed with (300 ohm) ladder line. And
I'm sure that the SWR on that line was out of whack.


But a folded dipole is nominally 300 ohm (292 ish). Am I misunderstanding the
magnitude of "not mattering much"? I had the image of people sticking a
quarter wave stick on the end of a ladder line and calling it good...


Mark Rand (Not a wireless person, even though I'm now doing wireless
networking at work)
RTFM

"Mark Rand" wrote in message
...
On Sat, 26 Sep 2009 14:44:31 -0400, "Ed Huntress"

wrote:



What Justme said has been common knowledge to ham radio operators for more
than half a century. SWR doesn't matter much with ladder line, partly
because of its low loss and partly because most of the antennas it's
usually
feeding are no great shakes themselves, and radiation from the
transmission
line is tolerable. I switched from a balun-type coax-fed dipole to a
ladder-line-fed folded dipole once, both of them in the exact same
position,
and I got much better reports on the one fed with (300 ohm) ladder line.
And
I'm sure that the SWR on that line was out of whack.


But a folded dipole is nominally 300 ohm (292 ish). Am I misunderstanding
the
magnitude of "not mattering much"? I had the image of people sticking a
quarter wave stick on the end of a ladder line and calling it good...

They might get away with it, too. g

At the HF bands most of us are familiar with, it's unusual to see simple
antennas that are high enough to avoid radiation distortion and impedance
distortion as a result of their proximity to the ground. If you have a VSWR
meter and a willingness to tune the whole affair, you can get good matches
all around. If not, you'd might as well feed the antenna with a low-loss
ladder line and be done with it. You'll get more radiative power out, in
most cases, even if some of it is coming off of the feedline.

--
Ed Huntress



Mark Rand (Not a wireless person, even though I'm now doing wireless
networking at work)
RTFM

Remember cellphones. Analogs had wip antennas that you pulled out...

Then the digital trend - antennas were internal.

What happened - range dropped and dropped. Analog can be used for miles.
Digital is good for a mile or two. It is also absorbed by pine trees
and is almost line of sight.

Martin

Ed Huntress wrote:
"Mark Rand" wrote in message
...
On Sat, 26 Sep 2009 14:44:31 -0400, "Ed Huntress"

wrote:


What Justme said has been common knowledge to ham radio operators for more
than half a century. SWR doesn't matter much with ladder line, partly
because of its low loss and partly because most of the antennas it's
usually
feeding are no great shakes themselves, and radiation from the
transmission
line is tolerable. I switched from a balun-type coax-fed dipole to a
ladder-line-fed folded dipole once, both of them in the exact same
position,
and I got much better reports on the one fed with (300 ohm) ladder line.
And
I'm sure that the SWR on that line was out of whack.

But a folded dipole is nominally 300 ohm (292 ish). Am I misunderstanding
the
magnitude of "not mattering much"? I had the image of people sticking a
quarter wave stick on the end of a ladder line and calling it good...

They might get away with it, too. g

At the HF bands most of us are familiar with, it's unusual to see simple
antennas that are high enough to avoid radiation distortion and impedance
distortion as a result of their proximity to the ground. If you have a VSWR
meter and a willingness to tune the whole affair, you can get good matches
all around. If not, you'd might as well feed the antenna with a low-loss
ladder line and be done with it. You'll get more radiative power out, in
most cases, even if some of it is coming off of the feedline.

On Sat, 26 Sep 2009 01:18:19 +0100, Mark Rand
wrote:

On Thu, 24 Sep 2009 13:22:16 -0700 (PDT), Tim Shoppa
wrote:

On Sep 23, 11:03*pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

Tim N3QE

VSWR isn't important anymore??


Mark Rand
RTFM

VSWR is important if:

1) it results in unacceptable voltage stress on components
2) it results in unacceptable I^2R losses in feedlines

Don Foreman, W0LAP

"Martin H. Eastburn" wrote in
:

Remember cellphones. Analogs had wip antennas that you pulled out...

Then the digital trend - antennas were internal.

What happened - range dropped and dropped. Analog can be used for
miles. Digital is good for a mile or two. It is also absorbed by pine
trees and is almost line of sight.

Martin

Ed Huntress wrote:
"Mark Rand" wrote in message
...
On Sat, 26 Sep 2009 14:44:31 -0400, "Ed Huntress"

wrote:

What Justme said has been common knowledge to ham radio operators
for more than half a century. SWR doesn't matter much with ladder
line, partly because of its low loss and partly because most of the
antennas it's usually
feeding are no great shakes themselves, and radiation from the
transmission
line is tolerable. I switched from a balun-type coax-fed dipole to
a ladder-line-fed folded dipole once, both of them in the exact
same position,
and I got much better reports on the one fed with (300 ohm) ladder
line. And
I'm sure that the SWR on that line was out of whack.

But a folded dipole is nominally 300 ohm (292 ish). Am I
misunderstanding the
magnitude of "not mattering much"? I had the image of people
sticking a quarter wave stick on the end of a ladder line and
calling it good...

They might get away with it, too. g

At the HF bands most of us are familiar with, it's unusual to see
simple antennas that are high enough to avoid radiation distortion
and impedance distortion as a result of their proximity to the
ground. If you have a VSWR meter and a willingness to tune the whole
affair, you can get good matches all around. If not, you'd might as
well feed the antenna with a low-loss ladder line and be done with
it. You'll get more radiative power out, in most cases, even if some
of it is coming off of the feedline.

The best gadget for calculating VSWR & mismatch losses is a plastic
slide rule from Phil Smith's (inventor of the Smith chart) "Analog
Instruments" company. Phil passed away a number of years ago, but his
wife was still selling stuff a few years back. I've been an RF engineer
for decades, and despite all of the modern CAD tools, I still use that
slide rule once or twice a week. We've got a problem with an antenna at
work, and I've been able to run instant loss calculations in the middle
of a meeting. Besides, when I fish it out & give out numbers in a
meeting, it enhances my senior guru status considerably.

I bought a whole stack of the slide rules a while back to give to the
younger engineers, but I think my stash is about gone. Most of the
youngsters have been conditioned to find a computer, locate a VSWR
calculator on Google, discover it doesn't do what they want, find a
couple more, and then finally come up with an answer. I can usually walk
back to my office, grab my slide rule & have an answer in less time.

Doug White

On Sat, 26 Sep 2009 01:18:19 +0100, Mark Rand wrote:
On Thu, 24 Sep 2009 13:22:16 -0700 (PDT), Tim Shoppa
On Sep 23, 11:03*pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

VSWR isn't important anymore??

I think not with ladder line (it's not very lossy), as long as you can
tune it out at the ends.

Shouldn't you be asking this in someplace like rec.radio.amateur.antennas ?

Cheers!
Rich

On Sat, 26 Sep 2009 14:20:56 -0400, Leon Fisk wrote:
On Sat, 26 Sep 2009 01:18:19 +0100, Mark Rand
On Thu, 24 Sep 2009 13:22:16 -0700 (PDT), Tim Shoppa
On Sep 23, 11:03*pm, "justme" wrote:
I GET DIFFERENT RESULTS WHEN COMPARING TO A GRAPH.

The exact impedance of ladder line is rarely critical; because of its
intrinsic low loss even large impedance mismatches are unimportant.

VSWR isn't important anymore??

Obviously not, just look at cell phones. The VSWR has to
really suck on them with all the crazy positions/places
people try using them. Solution, add more towers so people
don't notice it.

And use fractal antennas. ;-)

Cheers!
Rich