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It's cold. It's dark. And the TDR you need is missing.

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David Ashton
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re: It's cold. It's dark. And the TDR you need is missing.
David Ashton   1/29/2011 10:38:33 PM
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Nice story. I kinda wish I'd worked in those days myself. Things were simpler, and engineers had more respect I think. Though finding a break in a transatlantic cable, armed only with an ohm-meter, probably was not that simple.

SkipF
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re: It's cold. It's dark. And the TDR you need is missing.
SkipF   1/27/2011 1:12:06 AM
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What about these guys who fixed a broken cable without a TDR...? http://blog.modernmechanix.com/2008/01/30/splicing-a-cable-in-mid-atlantic/

warnnyjames
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re: It's cold. It's dark. And the TDR you need is missing.
warnnyjames   1/25/2011 11:55:24 AM
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gayatrikumar_1
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re: It's cold. It's dark. And the TDR you need is missing.
gayatrikumar_1   1/25/2011 4:18:46 AM
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Good Work !

richardst
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re: It's cold. It's dark. And the TDR you need is missing.
richardst   1/21/2011 10:03:04 AM
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Oops! You are quite right, JerrySC. I should have read more carefully.

Jerrysc
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re: It's cold. It's dark. And the TDR you need is missing.
Jerrysc   1/21/2011 2:14:25 AM
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Out FOR calibration is different than out OF calibration. The former means none available. With all the emphasis on doing everything from a computer, I wondered if engineers were still being educated in basic measurements.

Betterthanalemur
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re: It's cold. It's dark. And the TDR you need is missing.
Betterthanalemur   1/20/2011 6:34:39 PM
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I have to ask, did you have some fancy tdr that just doesn't turn on when it is out of cal?

Jonathan Allen
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re: It's cold. It's dark. And the TDR you need is missing.
Jonathan Allen   1/20/2011 1:42:45 PM
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Using the same theory as Richardst, a couple of years ago I faced a short an unknown distance along about 50 ft. of co-ax. I connected a small 3-turn coil across the feed end and used a grid-dip meter to find the resonant frequency. From this I predicted the location of the short and that's where it was. All with just one active device (a triode).

richardst
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re: It's cold. It's dark. And the TDR you need is missing.
richardst   1/20/2011 11:07:37 AM
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The TDR was out of calibration? Bung it onto the 1000 ft cable and check it. While a square wave or a pulse is easier, you should also be be able to do this with a sin signal generator. An open looks like a short at lambda/4 + n lambda/2. A short looks like a short at n lambda/2. Lambda = velocity-of-propagation (Vp) / frequency. For coax, take Vp as 2e8 m/s as a first try.

smitjs
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re: It's cold. It's dark. And the TDR you need is missing.
smitjs   1/20/2011 5:32:48 AM
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Maar natuurlik David Johan Smit

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