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 Why is coax unbalanced ?
ladder line is called a balanced line . Coax is called unbalanced . Why ? That means there are unequal currents flowing in the shield and the center conductor , right ? Why wud this be so ?
I'm missing something really simple here but I cannot put my finger on it.
k5jyd
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Coax has three conductors, the center conductor, the inside of the shield, and the outside of the shield. Ideally, all the shield current is on the inside, but it is certainly possible to have outside shield currents.
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 Originally Posted by W1VT
Coax has three conductors, the center conductor, the inside of the shield, and the outside of the shield. Ideally, all the shield current is on the inside, but it is certainly possible to have outside shield currents.
Beat me by seconds!!!
73
Mark, K8MHZ
"The best number is 73. Why? 73 is the 21st prime number. Its mirror (37) is the 12th and its mirror (21) is the product of multiplying, 7 and 3. ... In binary, 73 is a palindrome, 1001001 which backwards is 1001001."
-Dr. Sheldon Cooper, (Jim Parsons), "Big Bang Theory"
"Just to invite your attention to "73" in Morse code--also a palindrome."
-W9JEF
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Just some food for thought.....
I have some big coax that has a hollow center conductor. Now do we have four paths? Is it now balanced?
73
Mark, K8MHZ
"The best number is 73. Why? 73 is the 21st prime number. Its mirror (37) is the 12th and its mirror (21) is the product of multiplying, 7 and 3. ... In binary, 73 is a palindrome, 1001001 which backwards is 1001001."
-Dr. Sheldon Cooper, (Jim Parsons), "Big Bang Theory"
"Just to invite your attention to "73" in Morse code--also a palindrome."
-W9JEF
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Originally Posted by K8MHZ
Just some food for thought.....
I have some big coax that has a hollow center conductor.
Damned mice.
A government which robs Peter to pay Paul can always depend on the support of Paul.
-- George Bernard Shaw
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Originally Posted by K8MHZ
Just some food for thought.....
I have some big coax that has a hollow center conductor. Now do we have four paths? Is it now balanced?
Durn, now I won't get any sleep tonite.
TOM K8ERV Montrose Colo
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I had some unbalanced feedline but after six months of intensive therapy, it's better now and off all the meds.
A government which robs Peter to pay Paul can always depend on the support of Paul.
-- George Bernard Shaw
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Originally Posted by K8MHZ
Just some food for thought.....
I have some big coax that has a hollow center conductor. Now do we have four paths? Is it now balanced?
No, but if you are exceptionally clever, and the coax large enough, you could use the hollow center conductor
for microwave wave guide.
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Originally Posted by K8MHZ
I have some big coax that has a hollow center conductor. Now do we have four paths? Is it now balanced?
Simple answer: The laws of physics prevents RF current from flowing on the inside of the hollow center conductor because any and all RF fields will cancel.
73, Cecil, www.w5dxp.com
Random length "tuned feeders" usually de-tune an antenna system (thus requiring a tuner).
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Originally Posted by K8MHZ
I have some big coax that has a hollow center conductor. Now do we have four paths?
No, not really. The inside of the center conductor is a waveguide below cutoff at frequencies where you are likely to use the coax. Electromagnetic energy inside the inner conductor will decay exponentially away from the cut end and by the time you get in a short distance the currents on the inside of the inner conductor will be nearly nothing.
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