Test CAT6 run that quit working?

JimS

Active Member
Have a run to a detached garage that has been in about a year.  Suddenly the connection is bad.  I have surge suppressors on both ends but it seems the issue is in the cable run itself.  I was out of town but it looks to have happened about the time of a 30 minute utility outage but not sure it is related.  No severe storms in the area that I could tell.  The connection to the router works fine at the equipment in the house and at the other end nothing (using equipment that works in other locations).  The lights by the network connector flash briefly when the cable is plugged in but then go out and stay out when normally one would light and the other would flash.  It's a buried line in conduit so  physical damage seems unlikely.  I will be checking for shorts and opens and if I find anything wrong do a TDR test to determine the location of the issue.  Thought I would post here for any ideas on testing or what might have happened.
 

wkearney99

Senior Member
I'd test the cable first, but most testers are only for continuity.  That'd at least tell you if there's a pair that's gone missing or, shorted between pairs.  If you had a fancier tested that did TDR measurements that might be additionally informative.
 
Then maybe with something 'disposable' on the house end (like an old router).  Could be the ethernet circuits in either end have gotten fried.  start with one side with something 'not important' and keep that in place and use something on the other end to see if a connection can be made.  

Lightning, surges and other power disruptions are fiendishly annoying in how they avoid all best attempts to stop them.  And there's nothing that says it couldn't also be a coincidence of rodent, insect, water or other environmental damage.
 

JimS

Active Member
It's not the equipment on either end or the surge suppressors.  I am thinking it may just be a failed crimp on the ends.  I don't have a ethernet cable tester so it will be with a multimeter.  My TDR is a pulse generator and oscilloscope - not a real TDR but it works well.  I have used it to find other issues several times. 
 
Pete, it is the 250ft run but not to the camera.  Both ends are inside and well protected from moisture.
 

wkearney99

Senior Member
I've run across a number of 'turned out to be a bad crimp' posts in other groups online.  All of them summer heat related.  Don't know what brand connectors or cable though.  But given the number that have been posted, you might not be on the wrong track to re-do the termination.
 

pete_c

Guru
Personally I would purchase an Ethernet cable tester.  The one I mentioned above is around $50 on Amazon and test the ends without the surge suppressors first.
 

JimS

Active Member
wkearney99 said:
I've run across a number of 'turned out to be a bad crimp' posts in other groups online.  All of them summer heat related.  Don't know what brand connectors or cable though.  But given the number that have been posted, you might not be on the wrong track to re-do the termination.
I am thinking you are right on this.  Now I just have to find my crimp tool since the ends are male plugs.  I have lost track of it....
 

Neurorad

Senior Member
Could also be water in the conduit. Buried conduit usually, eventually, collects water. Cable rated for direct burial?
 

JimS

Active Member
Neurorad said:
Could also be water in the conduit. Buried conduit usually, eventually, collects water. Cable rated for direct burial?
Yes, the cable is direct burial and in conduit so damage to the cable seems unlikely.  Just got through reterminating both ends.  Still no go.  So I put together some jacks with a different resistance on each pair and discovered I got the wire order backwards on one end.  (I hate terminating male ends!)  Got that fixed and resistances check out but still no go.  I can plug a laptop into the jack the cable goes into on one end and it works.  Plug in through the cable at the other end and it doesn't.  It's late so it will have to wait for another day...
 

Frunple

Active Member
JimS said:
Yes, the cable is direct burial and in conduit so damage to the cable seems unlikely.  
 
I wouldn't be so sure about that. I've worked in some form of communication my whole life, one thing never changed, the ground below us is constantly moving and shifting.
Can't tell you how many times we ran a new conduit only to have it crushed in a matter of years.
Can you pull the wire at all? If the conduit is still good you should be able to.
Might need a TDR to measure the cable and start digging at the length it shows.
 

wkearney99

Senior Member
When this thread started, and Pete mentioned the Klein tester, I ordered one via eBay for $60. https://www.ebay.com/itm/274898288464

It came two days ago, and I've since used it to debug a wonky cable for a chart plotter on my boat.  Turned out some git had SPLICED the wires, and the tester pointed me to the break by distance.
 

JimS

Active Member
Did TDR on each pair and pair to pair - all looks good.  Shorted each wire to another on one end and checked resistance at the other end and all were consistent and what the resistance per foot predicted (within the accuracy of the meter).  Checked that wires were in the proper places in the connectors.  Also checked resistance using cables on each side of the surge supressor and through the supressor to check the whole path.  It looks good too.  I switched ports on the switch thinking it might be the port.  Have switched equipment at the other end.  Don't know what else to check.  Will put plugs on the spare cable that is already in place...
 

JimS

Active Member
Put a switch in place of the house surge protector temporarily as a test and everything is working.  The run between buildings is about 250'.  Then a protector on each end and then about 30' on one end to the wiring closet and about 6' on the other end to a switch.  Apparently it was just a bit too much?  I was under the impression I might get slow downs but didn't expect total non-functioning.  I am near the limit of 330 ft and the protectors probably should be counted as some length although I have no idea how much. 
 
I put the protector back in line and put the switch near it with a short patch cable and then the 30' cable to the wiring closet.  Seems to work ok but I suppose I should check the speed or errors - how would I do that?
 
My protectors are DTK MRJPOE.  The installation instructions say to use a 3' patch cable between the protector and equipment but I thought I had seen somewhere that was a minimum.
 
Also puzzling that it worked for several weeks before stopping (when I was out of town of course!).
 

pete_c

Guru
Seems to work ok but I suppose I should check the speed or errors - how would I do that?
 
Best to use a cable testing tool as suggested above.
 
There is Windows software to be able to test ...speed and errors ...you will need two laptops to test...

[SIZE=large]Qcheck User Guide[/SIZE]
 

JimS

Active Member
Did some testing using just the cable (no protectors either end). Connected to a router on one end and a PC on the other. If I connect directly to the router with a short cable the status shows Gb speed. When going through the cable it shows 10Mb speed. All the pings go through with reasonable time numbers. Any idea what might be causing this? Moisture in the cable? It is Cat6 cable rated for direct burial, think it was described as gel tape. I will look up the details.
 
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