Thread: Cable Loss Measurment (Attenuation) using Network Analyzer


Permlink Replies: 2 - Pages: 1 - Last Post: Aug 27, 2012 4:24 AM Last Post By: drkirkby Threads: [ Previous | Next ]
Indian4201

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Registered: 01/26/12
Cable Loss Measurment (Attenuation) using Network Analyzer
Posted: Jan 26, 2012 7:31 PM
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Hi,

I am new to Network Analyzer E5071C. i am familiar with performing through connection via using two short cable and making a through connection and then having Cable under Test (CUT) in between to measure the loss.

But, I have a situation where cable is already laid under the decks and It is 200 ft cable that can not be taken out to perform Through Connection calibration. Thus need to know what is the other option to measure the loss through this cable using this network analyzer.

Please help.
Dr_joel


Posts: 2,671
Registered: 12/01/05
Re: Cable Loss Measurment (Attenuation) using Network Analyz
Posted: Jan 27, 2012 12:53 AM   in response to: Indian4201 in response to: Indian4201
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Any idea of the frequency range and/or expected loss? We do have a method (patented) for making one-way cable-loss measurements. 200 feet might be a bit long. Can you access both ends of the cable (i.e. get to the connectors?). Send me a PM, along with the name of your Agilent rep and we can see about sorting you out on this.
drkirkby

Posts: 549
Registered: 06/18/08
Re: Cable Loss Measurment (Attenuation) using Network Analyzer
Posted: Aug 27, 2012 4:24 AM   in response to: Indian4201 in response to: Indian4201
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Can you disconnect the far end of the cable, or better still terminate it in a short circuit? If so, the attenuation one way will be half the return loss. So if you measure a return loss of 10 dB, you know there's 5 dB of attenuation. You need access to both ends of the cable, but don't need to run a 200 foot cable to do the job.

That makes some assumptions about the cable being 50 Ohms, but as long as the attenuation is not too high, the reflected signal wlll be dominated by the reflection, and not the imperfections in the impedance of the cable.

Dave

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