Help me in weird insertion loss problem in cat6F/UTP

[OmidGh]

Dear friends,
Recently I got a cat6F/UTP. When I run permanent link test on it with DTX1800 fluke analyzer, I get marginal insertion loss(-0.2dB) failure just at low frequency (~3MHz) on all pairs. In higher frequency, the insertion loss is good and fairly below the limit margin!!.
When I run the channel test on this cable, the test is passed and the headroom on insertion loss @250 MHz is about 10 dB for all pairs. Can you help me what is the problem? is it the cable issue or connectors.

 

[Wanebo]

Reterminate both ends preferably to new jacks/ports and retest. If that doesn't resolve it then it's possible you have some bad cable.

 

[libellis]

Could be Cat 6 copper clad aluminum cable. Check the resistance measurement and compare to what would be expected for copper at the distance and wire gauge of the cable. Also, scrape the copper and see if there is aluminum beneath. If it turns out to be copper clad, replace it with real Cat 6 cable.

 

[Professor Shadow]

Definitely check for counterfeit cable. UL-444 can be forged.

NEC 800.179 Communications Wires and Cables. Communication wires and cables shall be listed in accordance with 800.179(A) through (I) and marked in accordance with Table 800.179. Conductors in communications cables, other than in a coaxial cable, shall be copper.

The 2017 (and 2014, 2011, 2008, 2005) NEC code book clearly does not allow CCA for communications...shall be.



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[Dexman]

In the same vein as the two replies above, what is the brand of the cable? Was it purchased from an authorized dealer?

I "FEATURE 00"

http://dexman.webs.com/

 

[libellis]

Copper clad aluminum cable will exhibit the described behavior. At higher frequencies, due to the "skin effect", current crowds to the outside of the conductor where the copper is located and attenuation won't differ so much from an all copper wire. However, at lower frequencies, where current will be flowing in both the aluminum and copper cladding, the attenuation will be higher than would be expected from a solid copper wire. Aside from this, there is the issue of performance with PoE since aluminum has a higher resistance.

 

[Professor Shadow]

At this point we can all speculate until the OP responds...if ever.

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"Thank you for calling Technical Support. If you feel you have reached this number in error, please hang up and try again." ~Jane Barbe