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Old June 30th 05, 10:55 PM
Cecil Moore
 
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Frank Gilliland wrote:
Regardless of it's location, you should -never- leave the
coupler floating with the coax or you will end up with results like
what you describe above.


The results above obey the laws of physics. What laws do your
results obey?
--
73, Cecil http://www.qsl.net/w5dxp

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Old June 30th 05, 10:57 PM
Steveo
 
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Cecil Moore wrote:
Frank Gilliland wrote:
Regardless of it's location, you should -never- leave the
coupler floating with the coax or you will end up with results like
what you describe above.


The results above obey the laws of physics. What laws do your
results obey?

You guys are just itchin' for a visit from the coax length police.
  #133   Report Post  
Old June 30th 05, 10:59 PM
Frank Gilliland
 
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On Thu, 30 Jun 2005 17:28:45 GMT, james wrote
in :

On Wed, 29 Jun 2005 17:59:24 -0700, Frank Gilliland
wrote:

On Thu, 30 Jun 2005 00:45:25 GMT, james wrote
in :

On Wed, 29 Jun 2005 17:17:53 -0700, Frank Gilliland
wrote:

That's basically what Lance said, just in different words. So what's
the problem?
*****

I have problems when people state "current flows". That is not
actually true.



So current -doesn't- flow?


Power in the electromagnetic wave that flows down a
transmission line and currents on the center conductor and outer
conductor are dependant on the E and H fields of the wave within the
transmission line at any point on the transmission line.



Those E and H fields are created by voltage and current introduced
onto the conductors. A transmission line simply establishes a kind of
self-propogating 'symbiosis' between the fields and the current &
voltage on the conductors. Current does indeed flow on those
conductors -- if it didn't they wouldn't be necessary.

******
Please correct me if I have misunderstood your position above. I am
trying to visualize what are saying.

Then it is your assertion that in a coax a sinusoidal current flows in
the center conductor to the load, then through the load and back to
the source through the shield?



I'm not going to educate you about transmission lines in a newsgroup.
It would take several large posts and I simply don't have the time to
write that much. If you want to understand how coax works then dig out
your EM textbook and review the basics.







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Old June 30th 05, 11:16 PM
Frank Gilliland
 
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On Thu, 30 Jun 2005 16:55:13 -0500, Cecil Moore
wrote in :

Frank Gilliland wrote:
Regardless of it's location, you should -never- leave the
coupler floating with the coax or you will end up with results like
what you describe above.


The results above obey the laws of physics. What laws do your
results obey?



The law of "been there, done that, and what I -thought- would happen
is not what -really- happened".






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Old July 1st 05, 12:36 AM
Walter Maxwell
 
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"Tom Ring" wrote in message
. ..
Walter Maxwell wrote:
Reading the mail appearing in this thread is more fun than watching Saturday
Night Live!

Walt, W2DU


Some of the people involved appear to be listening from inside Faraday Cages!

tom
K0TAR


Faraday used the cages after the monkeys were through with them. The monkeys
left them so fouled up that EM waves couldn't penetrate the walls.

Walt, W2DU




  #136   Report Post  
Old July 1st 05, 05:30 AM
Scott in Baltimore
 
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But I specifically stated above the Z0 environment was different
from 50 ohms. The same type of error happens when one uses a
50 ohm SWR meter in a 75 ohm coaxial line.


If that were true then the mere existence of standing waves could
render any measurements worthless. Regardless, I did the experiment a
long time ago -- take a 50 ohm SWR meter and plug it into a 75 ohm
line -- it gives you almost the same measurement (in fact, I didn't
see -any- difference at all). Any small error you might see is, as I
said before, insignificant, especially considering the reason you are
measuring SWR in the first place. The objective is simply to get the
reading as low as practially possible. If you feel the need to quibble
about a couple tenths of a point on a ratio then maybe you're spending
a little too much time playing with the calculator instead of the
antenna.



I'm running RG-6 out to my 2 meter antenna. I put my cheap RS HF meter inline
to see what I'd read. I got my expected 1.5:1. Wattage read 1/2 of what the
radio is rated for. It gets out and I'm not worried about it.
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Old July 2nd 05, 08:31 PM
james
 
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On Thu, 30 Jun 2005 14:59:31 -0700, Frank Gilliland
wrote:

I'm not going to educate you about transmission lines in a newsgroup.
It would take several large posts and I simply don't have the time to
write that much. If you want to understand how coax works then dig out
your EM textbook and review the basics.

*****

I am not seeking your education just seeking better understanding of
your position.

But yes I think this has gone well to far.

james
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