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is this an EM wave
|
|
| dysfunctionally_yours 2006-03-12, 3:21 am |
| if i pass alternatin current through an infinitely long and perfectly
straight wire, would i get an electromagnetic wave?
is there any manner in which i can detect whether or not these waves
are produced?
| |
| Rheilly Phoull 2006-03-12, 8:21 am |
|
"dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
news:1142146191.468412.268210@u72g2000cwu.googlegroups.com...
> if i pass alternatin current through an infinitely long and perfectly
> straight wire, would i get an electromagnetic wave?
> is there any manner in which i can detect whether or not these waves
> are produced?
>
First get the infinitely long straight wire !!!
--
Regards ......... Rheilly Phoull
| |
|
|
"dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
news:1142146191.468412.268210@u72g2000cwu.googlegroups.com...
> if i pass alternatin current through an infinitely long and perfectly
> straight wire, would i get an electromagnetic wave?
Yes - but it doesn't have to be infinitely long or perfectly straight.
> is there any manner in which i can detect whether or not these waves
> are produced?
A radio receiver?
| |
| TimPerry 2006-03-12, 2:21 pm |
|
"dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
news:1142146191.468412.268210@u72g2000cwu.googlegroups.com...
> if i pass alternatin current through an infinitely long and perfectly
> straight wire, would i get an electromagnetic wave?
> is there any manner in which i can detect whether or not these waves
> are produced?
>
An infinitely long wire would have infinite resistance therefore zero
current would pass through it therefore no waves of any kind would be
produced.
| |
|
| On Sun, 12 Mar 2006 12:57:05 -0500, TimPerry wrote:
>
> "dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
> news:1142146191.468412.268210@u72g2000cwu.googlegroups.com...
>
> An infinitely long wire would have infinite resistance therefore zero
> current would pass through it therefore no waves of any kind would be
> produced.
Really? Ever heard of a transmission line?
--
Keith
| |
| marcmccomb@hotmail.com 2006-03-12, 8:21 pm |
| the signal through a transmission wire needs to be buffered or repeated
| |
| **THE-RFI-EMI-GUY** 2006-03-12, 10:21 pm |
| Yes, but he implies that a current is being drawn whih implies an
infinitely high voltage must be present.
TimPerry wrote:
>"dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
>news:1142146191.468412.268210@u72g2000cwu.googlegroups.com...
>
>
>
>An infinitely long wire would have infinite resistance therefore zero
>current would pass through it therefore no waves of any kind would be
>produced.
>
>
>
>
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©
"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."
"Follow The Money" ;-P
| |
| Keith 2006-03-12, 11:21 pm |
| On Sun, 12 Mar 2006 16:07:17 -0800, marcmccomb@hotmail.com wrote:
> the signal through a transmission wire needs to be buffered or repeated
Think about what you've written again. Do the Voyager probes need to
"buffer or repeat" what they've sent?
No, a transmission line looks like its characteristic impedance to the
driver, no matter *how* long the line is. Current *will* travel in the
line until it's absorbed by the R and D components, even beyond detection.
--
Keith
| |
| Keith 2006-03-13, 12:21 am |
| On Mon, 13 Mar 2006 01:45:00 +0000, **THE-RFI-EMI-GUY** wrote:
If you want anyone to read what you've written (and I assume you do since
you toook the time), do *NOT* post HTML. Only a fool will bother.
--
Keith
| |
| **THE-RFI-EMI-GUY** 2006-03-13, 12:21 am |
| I have no idea what you are talking about.....plonk!
Keith wrote:
>On Mon, 13 Mar 2006 01:45:00 +0000, **THE-RFI-EMI-GUY** wrote:
>
>If you want anyone to read what you've written (and I assume you do since
>you toook the time), do *NOT* post HTML. Only a fool will bother.
>
>
>
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©
"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."
"Follow The Money" ;-P
| |
| Keith 2006-03-13, 12:21 am |
| On Mon, 13 Mar 2006 03:20:09 +0000, **THE-RFI-EMI-GUY** wrote:
> I have no idea what you are talking about.....plonk!
You posted with HTML, which is unreadable by most and certainly not a
Usenet norm. Post in test only, moron! Oh, you won't listen because you
plonked me, rather than learning from *YOUR* misteaks. Go figgr.
As a hint, this is what you posted (looks like HTML to me...:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//E N">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1"
http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000"> Yes, but he implies that a
current
is being drawn whih implies an infinitely high voltage must be
present.<br> <br>
TimPerry wrote:
<blockquote cite="mid16udnWCKytBv_YnZRVn-jA@adelphia.com" type="cite">
<pre wrap="">"dysfunctionally_yours" <a class="moz-txt-link-rfc2396E"
href="mailto:sujay.dsa@gmail.com"><sujay.dsa@gmail.com></a>
wrote
in message
<a class="moz-txt-link-freetext"
href="news:1142146191.468412.268210@u72g2000cwu.googlegroups.com">news:1142146191.468412.268210@u72g2000cwu.googlegroups.com</a>...
</pre>
<blockquote type="cite">
<pre wrap="">if i pass alternatin current through an infinitely long
and perfectly
straight wire, would i get an electromagnetic wave? is there any manner
in
which i can detect whether or not these waves are produced?
</pre>
</blockquote>
<pre wrap=""><!---->
An infinitely long wire would have infinite resistance therefore zero
current would pass through it therefore no waves of any kind would be
produced.
</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©
"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."
"Follow The Money" ;-P
</pre>
</body>
</html>
....you may apologize now.
--
Keith
| |
| Don Kelly 2006-03-13, 1:21 am |
| I got it alright but some still receive "plain text" so the formatting is
lost and HTML headers come through as extraneous header information. Plain
text is simply a courtesy to those that have HTML problems. It is too bad
because HTML does allow more latitude in what is sent.
--
Don Kelly @shawcross.ca
remove the X to answer
----------------------------
"**THE-RFI-EMI-GUY**" <rhyolite@nettally.com> wrote in message
news:4414E538.8040103@nettally.com...
>I have no idea what you are talking about.....plonk!
>
> Keith wrote:
>
>
> --
> Joe Leikhim K4SAT
> "The RFI-EMI-GUY"©
>
> "Treason doth never prosper: what's the reason?
> For if it prosper, none dare call it treason."
>
> "Follow The Money" ;-P
>
| |
| Don Kelly 2006-03-13, 1:21 am |
| This is HTML while the previous was plain text
I got it alright but some still receive "plain text" so the formatting is lost and HTML headers come through as extraneous header information(look like garbage). Plain text is simply a courtesy to those that have HTML problems. It is too bad because HTML does allow more latitude in what is sent.
--
Don Kelly @shawcross.ca
remove the X to answer
--
Don Kelly @shawcross.ca
remove the X to answer
----------------------------
"**THE-RFI-EMI-GUY**" <rhyolite@nettally.com> wrote in message news:4414E538.8040103@nettally.com...
>I have no idea what you are talking about.....plonk!
>
> Keith wrote:
>
>
> --
> Joe Leikhim K4SAT
> "The RFI-EMI-GUY"©
>
> "Treason doth never prosper: what's the reason?
> For if it prosper, none dare call it treason."
>
> "Follow The Money" ;-P
>
| |
| Salmon Egg 2006-03-13, 4:21 am |
| On 3/11/06 10:49 PM, in article
1142146191.468412.268210@u72g2000cwu.googlegroups.com,
"dysfunctionally_yours" <sujay.dsa@gmail.com> wrote:
> if i pass alternatin current through an infinitely long and perfectly
> straight wire, would i get an electromagnetic wave?
> is there any manner in which i can detect whether or not these waves
> are produced?
>
Only if seven angels can dance on the head of a pin.
Bill
-- Ferme le Bush
| |
| dysfunctionally_yours 2006-03-13, 12:21 pm |
| ok. im not sure where this is heading, but if the line is a
superconductor, and has no impedance, and i somehow inject a current
into it, will i get an EM wave?
as far as transmission lines are concerned , thoough i cannot say for
sure, there is one EM wave which moves along the length of the line
uptil the point it is terminated, and another may be due to corona
| |
| Keith Williams 2006-03-13, 12:21 pm |
| In article <1142263569.236071.100680@j33g2000cwa.googlegroups.com>,
sujay.dsa@gmail.com says...
> ok. im not sure where this is heading, but if the line is a
> superconductor, and has no impedance, and i somehow inject a current
> into it, will i get an EM wave?
A superconducting transmission line will still have an impedance.
In a super conductor 'R' may go to zero, but there is still a non-
zero 'C', 'L', and 'D' term. Where there no inductance, for
example, we wouldn't have superconducting magnets nor SQUIDs.
> as far as transmission lines are concerned , thoough i cannot say for
> sure, there is one EM wave which moves along the length of the line
> uptil the point it is terminated,
If the transmission line is infinitely long, there is no
terminator. ;-)
> and another may be due to corona
I'd have to think about corona some more, but first SWAG I'd lump
it in with the 'D' term.
--
Keith
| |
| dysfunctionally_yours 2006-03-13, 1:21 pm |
| as far as inductive emf is concerned, though i may not be right , but i
believe that it comes into the picture only if the magnetic field of
the current carrying conductor links itself. if the line were perfectly
straight ( and note that my original question was purely conceptual,
assuming all ideal cases) the magnetic field of the conductor would not
link any part of the conductor and hence no effect.
would there be any inductance if there were absolutely, and ideally no
twists and turns?
| |
| TimPerry 2006-03-13, 1:21 pm |
|
"dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
news:1142263569.236071.100680@j33g2000cwa.googlegroups.com...
> ok. im not sure where this is heading, but if the line is a
> superconductor, and has no impedance, and i somehow inject a current
> into it, will i get an EM wave?
no: the short circuit will burn up the current source.
(plus an infinitely long wire that had any mass/distance would fill all
available space in the universe)
do you have a practical objective in mind or are you just wondering?
>
> as far as transmission lines are concerned , thoough i cannot say for
> sure, there is one EM wave which moves along the length of the line
> uptil the point it is terminated, and another may be due to corona
>
| |
| Keith Williams 2006-03-13, 3:21 pm |
| In article <1142266641.752799.295240@i39g2000cwa.googlegroups.com>,
sujay.dsa@gmail.com says...
> as far as inductive emf is concerned, though i may not be right , but i
> believe that it comes into the picture only if the magnetic field of
> the current carrying conductor links itself. if the line were perfectly
> straight ( and note that my original question was purely conceptual,
> assuming all ideal cases) the magnetic field of the conductor would not
> link any part of the conductor and hence no effect.
>
> would there be any inductance if there were absolutely, and ideally no
> twists and turns?
>
>
Yes. Even free space has a characteristic impedance (377ohms, if
memory serves).
--
Keith
| |
| Dave Holford 2006-03-13, 6:21 pm |
|
TimPerry wrote:
> "dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
> news:1142146191.468412.268210@u72g2000cwu.googlegroups.com...
>
Well, those long transmission lines from Labrador, through Quebec and into
New England may not be infinite but they are pretty long, and the 60 Hz AC
in them certainly radiates something that makes my portable frequency meter
read 60 Hz when I drive under them.
Dave
| |
| Salmon Egg 2006-03-13, 10:21 pm |
| On 3/13/06 8:30 AM, in article
k5adnSn286q7A4jZnZ2dnUVZ_sydnZ2d@adelphia.com, "TimPerry"
<timperry@noaspamadelphia.net> wrote:
> "dysfunctionally_yours" <sujay.dsa@gmail.com> wrote in message
> news:1142263569.236071.100680@j33g2000cwa.googlegroups.com...
>
> no: the short circuit will burn up the current source.
>
> (plus an infinitely long wire that had any mass/distance would fill all
> available space in the universe)
>
> do you have a practical objective in mind or are you just wondering?
A current source has no problem with a short circuit. It is an open circuit
that will give trouble.
Bill
-- Ferme le Bush
| |
| Salmon Egg 2006-03-13, 10:21 pm |
| On 3/13/06 1:33 PM, in article 4415E525.72FEA4A@sympatico.ca, "Dave Holford"
<holford@sympatico.ca> wrote:
> Well, those long transmission lines from Labrador, through Quebec and into
> New England may not be infinite but they are pretty long, and the 60 Hz AC
> in them certainly radiates something that makes my portable frequency meter
> read 60 Hz when I drive under them.
Be sure that you are not mixing up radiative coupling with inductive or
capacitive coupling.
Bill
-- Ferme le Bush
| |
|
| On Tue, 14 Mar 2006 02:02:22 +0000, Salmon Egg wrote:
> On 3/13/06 8:30 AM, in article
> k5adnSn286q7A4jZnZ2dnUVZ_sydnZ2d@adelphia.com, "TimPerry"
> <timperry@noaspamadelphia.net> wrote:
>
>
> A current source has no problem with a short circuit. It is an open circuit
> that will give trouble.
As long as we assume an infinitly long and straight conductor, why not
assume an infinite voltage to go along with it? ;-)
--
Keith
| |
| Keith Williams 2006-03-14, 11:21 am |
| In article <4415E525.72FEA4A@sympatico.ca>, holford@sympatico.ca
says...
>
>
> TimPerry wrote:
>
>
> Well, those long transmission lines from Labrador, through Quebec and into
> New England may not be infinite but they are pretty long, and the 60 Hz AC
> in them certainly radiates something that makes my portable frequency meter
> read 60 Hz when I drive under them.
>
Are they long WRT wavelength? ;-)
--
Keith
| |
| TimPerry 2006-03-16, 12:21 am |
|
"Keith" <krw@att.bizzzz> wrote in message
news:pan.2006.03.14.05.18.58.491665@att.bizzzz...
> On Tue, 14 Mar 2006 02:02:22 +0000, Salmon Egg wrote:
>
circuit[color=darkred]
>
> As long as we assume an infinitly long and straight conductor, why not
> assume an infinite voltage to go along with it? ;-)
>
> --
> Keith
any voltage from zero to infinite into a zero ohm load will result in zero
transfer of energy.
look up antenna radiation resistance
infinite voltage into a finite load would result in infinite power and
probably destroy the entire universe.
if it's a very long wire, but not infinite, you can use it to talk to
submarines (see project elf)
if its long but not extremely long, load it up on 160 meters (see beverage
antenna)
| |
| Keith 2006-03-16, 12:21 am |
| On Wed, 15 Mar 2006 22:27:31 -0500, TimPerry wrote:
>
> "Keith" <krw@att.bizzzz> wrote in message
> news:pan.2006.03.14.05.18.58.491665@att.bizzzz...
> circuit
>
> any voltage from zero to infinite into a zero ohm load will result in zero
> transfer of energy.
oo/0 is undefined.
> look up antenna radiation resistance
Have you a zero ohm antenna?
> infinite voltage into a finite load would result in infinite power and
> probably destroy the entire universe.
....and would take the entire universe to gen...
>
> if it's a very long wire, but not infinite, you can use it to talk to
> submarines (see project elf)
Of course, but now you're going into the mundane real world. AIUI, ELF
really modulates the Earth's magnetic field.
> if its long but not extremely long, load it up on 160 meters (see beverage
> antenna)
If it's anything like l/20 load it up to whatever you want. If it's a
"beverage antenna", isn't it you that gets loaded?
--
Keith
| |
| chuck 2006-03-16, 10:21 am |
| Think about this:
If the antenna is infinitely long (or even just awfully darned long in
reference to what we normally imagine for antennas) then you can look at
say the first half-wavelength of wire and consider the remaining (still
infinite by definition of infinity because you can't make something that
is infinite become finite by subtracting a finite amount from it) length
of wire to constitute an open circuit. You have a half-wavelength
antenna with an infinite resistance at the far end of it.
So you do that and get an answer.
See: the question seemed to be reasonable and the answer meaningful.
But now you look at some other finite length (say a quarter-wavelength)
in a similar way and get another answer.
You find the two answers are contradictory. Both cannot be
simultaneously true.
You conclude one or more of your assumptions is in error, and in this
case, it is the infinite length of the wire.
No meaningful information can be obtained from the assumption of an
infinite antenna length.
I will not nit-pick the infinitely long/perfectly straight assumption.
Good exercise.
Chuck
dysfunctionally_yours wrote:
> if i pass alternatin current through an infinitely long and perfectly
> straight wire, would i get an electromagnetic wave?
> is there any manner in which i can detect whether or not these waves
> are produced?
>
| |
| Keith 2006-03-16, 10:21 pm |
| On Thu, 16 Mar 2006 13:57:04 +0000, chuck wrote:
> Think about this:
>
> If the antenna is infinitely long (or even just awfully darned long in
> reference to what we normally imagine for antennas) then you can look at
> say the first half-wavelength of wire and consider the remaining (still
> infinite by definition of infinity because you can't make something that
> is infinite become finite by subtracting a finite amount from it) length
> of wire to constitute an open circuit. You have a half-wavelength
> antenna with an infinite resistance at the far end of it.
Ok, but it it's a little shorter than oo-lambda... ;-)
> So you do that and get an answer.
>
> See: the question seemed to be reasonable and the answer meaningful.
Yes it does, if the wire is very long compared to the voltage applied.
However, a finite (unterminated) wire will eventually reflect the voltage
you stuck on it.
> But now you look at some other finite length (say a quarter-wavelength)
> in a similar way and get another answer.
>
> You find the two answers are contradictory. Both cannot be
> simultaneously true.
Where is the contradiction?
> You conclude one or more of your assumptions is in error, and in this
> case, it is the infinite length of the wire.
As long as twice the length of the wire (times 'C') is longer than my
life, no, I really don't care. It's close enough to infinite length.
> No meaningful information can be obtained from the assumption of an
> infinite antenna length.
Bullshit. I can deduce the characteristic impedance from an infinite
length antenna. I can measure the voltage and current at the antenna
terminals. That tells me quite a lot.
> I will not nit-pick the infinitely long/perfectly straight assumption.
As long as it's longer and straigheter than our time of interest, it's
"infinite". The concept of infinity has meaning. If I take an infinitely
long wire passing over an infinite plane, and connect an ohm meter to one
end and the plane, what do I measure.
> Good exercise.
"Infinite" wires are good exercises. I thought you just said there was
nothing to be learned from contemplating them. No?
--
Keith
| |
| chuck 2006-03-16, 10:21 pm |
| Keith wrote:
> However, a finite (unterminated) wire will eventually reflect the voltage
> you stuck on it.
>
I don't follow what you're saying here. The OP asked about whether he
would get an EM wave. An end-fed half-wave wire with an open circuit at
the other end will surely radiate.
My point was that depending on how you set up the problem, you can get
different answers. To me, that suggests contradiction.
>
> Bullshit. I can deduce the characteristic impedance from an infinite
> length antenna. I can measure the voltage and current at the antenna
> terminals. That tells me quite a lot.
Your position is that if someone shows you an infinitely long antenna,
then you'll deduce its characteristic impedance?
Will you also be able to describe radiation patterns for it?
Where will you measure e and i? One terminal to the wire and the other
to some convenient place?
Could you deduce the characteristic impedance without having the antenna
before you?
If I take an infinitely
> long wire passing over an infinite plane, and connect an ohm meter to one
> end and the plane, what do I measure.
>
What do you measure? Are they in infinite space?
>
>
>
> "Infinite" wires are good exercises.
They do tend to be monotonous.
I thought you just said there was
> nothing to be learned from contemplating them. No?
Not exactly. I'm still not sure what I've learned here. I'm waiting to
hear your answer to the OP and to see the reasoning behind it. So don't
give up yet . . . I'm anxious to learn, kidding aside! ;)
Chuck
>
| |
| Keith 2006-03-17, 12:21 am |
| On Fri, 17 Mar 2006 02:07:50 +0000, chuck wrote:
> Keith wrote:
>
>
>
> I don't follow what you're saying here. The OP asked about whether he
> would get an EM wave. An end-fed half-wave wire with an open circuit at
> the other end will surely radiate.
It doesn't have to be a half wave to radiate. An infinite wire will
radiate, as will a 1/20 wavelength. Launch a step (or impulse) down a wire
and tell me that it's not going to radiate. The EM wave is moving town
the t-line; it's going to radiate.
> My point was that depending on how you set up the problem, you can get
> different answers. To me, that suggests contradiction.
No contradictions.
>
> Your position is that if someone shows you an infinitely long antenna,
> then you'll deduce its characteristic impedance?
Yep. Measure the current and voltage (S11).
> Will you also be able to describe radiation patterns for it?
Pattern, certainly not. I'm only looking at one terminal.
> Where will you measure e and i? One terminal to the wire and the other
> to some convenient place?
Ok, if you have no "ground", are you driving the wire? If a tree...
> Could you deduce the characteristic impedance without having the antenna
> before you?
Could "I"? Likely not, but it seems that the math's gotta work.
> If I take an infinitely
>
> What do you measure? Are they in infinite space?
"Infinite" to as good of an aproximation as I care to test.
>
> They do tend to be monotonous.
I know, like this thread, they go on forever. "Are we there yet?"
> I thought you just said there was
>
> Not exactly. I'm still not sure what I've learned here. I'm waiting to
> hear your answer to the OP and to see the reasoning behind it. So don't
> give up yet . . . I'm anxious to learn, kidding aside! ;)
Contemplating the infinite tells us a lot. ...like the ohmmeter on the
infinite transmission line.
--
Keith
| |
| Robbie Mayhem 2006-03-17, 9:21 am |
|
"chuck" <nospam@nospam.net> wrote in message
news:WRoSf.5459$k75.2975@newsread3.news.atl.earthlink.net...
> Keith wrote:
>
An end-fed half-wave wire with an open circuit at
> the other end will surely radiate
[color=darkred]
> Chuck
Doesn't having another end imply a wire of finite length?
Rob
| |
| chuck 2006-03-17, 10:21 am |
| In-Reply-To: <TOKdnVvwbu0GMIfZRVnyuw@pipex.net>
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Rob, go back to my original post to see where I was going with this.
Let me ask you whether a wire of finite length that has something with
infinite resistance (i.e., an infinitely long wire) on one end is of
finite or infinite length?
Chuck
Robbie Mayhem wrote:
> "chuck" <nospam@nospam.net> wrote in message
> news:WRoSf.5459$k75.2975@newsread3.news.atl.earthlink.net...
>
>
> An end-fed half-wave wire with an open circuit at
>
>
>
>
>
> Doesn't having another end imply a wire of finite length?
>
> Rob
>
>
| |
| Robbie Mayhem 2006-03-17, 4:21 pm |
|
"chuck" <nospam@nospam.net> wrote in message
news:EdzSf.13607$S25.10625@newsread1.news.atl.earthlink.net...[color=darkred]
> Rob, go back to my original post to see where I was going with this.
>
> Let me ask you whether a wire of finite length that has something with
> infinite resistance (i.e., an infinitely long wire) on one end is of
> finite or infinite length?
>
> Chuck
>
>
> Robbie Mayhem wrote:
As you state above, it is clearly a wire of finite length. But an infinite
resistance on one end? Hmmm! Not sure about that! Mathematically speaking,
you should try and avoid dealing with infinities where possible. I suppose
you could talk about how the wave function behaves as it tends to infinity.
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| On Fri, 17 Mar 2006 13:55:48 +0000, chuck wrote:
> Rob, go back to my original post to see where I was going with this.
>
> Let me ask you whether a wire of finite length that has something with
> infinite resistance (i.e., an infinitely long wire) on one end is of
> finite or infinite length?
....but an infinitely long wire doesn't have infinite resistance. If you
hook an ohmmeter to it it'll show it's characteristic impedance (until
the D/R components bleed the current on the line). If you hook the same
ohmmeter to a finitely long wire terminated with an infinite resistor, the
ohmmeter will read the characteristic impedance until twice the length of
the wire and then see the reflection from the end.
Please don't top-post. It makes following your point more difficult.
--
Keith
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