RG59 Cable fault Find?

[Kylinho]

Hi,

Tested a 100m RG59 cable and no signal was coming through. Replaced the BNC connectors and the problem persists, no breakage is visible on the cable.

Is there a tool I can use to find the fault in the cable? Any other trouble shooting advice, would like to avoid cutting the cable at multiple intervals to locate the fault.

Thank you.

 

[InusB]

Have you tested with a multimeter to check if it doesn't have a short?

This tester shows the info you need for CAT5 & 6 cables and it does have a F Connector port for Coax cable.

If you know someone in the industry with this tester that can help you out, you should be able to identify the problem quickly.
Have to say I have never used this tester on coax.

 

[Kylinho]

Have not tested if there is a short.

I do not know anyone in the industry. So obtaining that tester will be a problem, cost of the tester would equal buying a new roll of cable.

Thank you for your help.

 

[Sosio]

Well as suggested, test if there is a short

Just hook up a multi meter between the braid and the core, if all is good you should read infinity, a short would definitely prevent the signal from coning through.

Then MAKE a short on one end, just wrap the braid around the core, and test again this time you expect a short if there still is no short it means the core is broken off somewhere. Have a look throughout the cable if you can for a kink or indications that the cable was kinked.

Then it depends what tools you have available to diagnose further. If you have a broken core you can detect it with most STUD detectors used for scanning walls for cables/pipes like this, you can get them at most hardware stores and they don't need to be this one, most of them have a function capable of detecting AC (like power cables). Then you could connect the core (or the braid although chances of that being broken is much slimmer) to a AC powersupply (don't connect to mains, will work but extremely dangerous), then scan the cable, just walk with the scanner past the cable the scanner will make a noise indicating the presence of AC, if it stops thats where your break is. Dont try this in the event of a short wont help then.

 

[Kylinho]

Sosio,

Thanks fella.

Will give it try today, I appreciate the help.

If there is a short then I have to replace the cable?

 

[Sosio]

Kylinho

In either event, short or open circuit your best bet is to first find the problem and see if you can fix it. Like with a simple cable joining cut, cut out the bad part and join it. Ideally you don't want any joins as they tend to degrade the signal, but you will have to see if what you get out is acceptable, one or two joins shouldn't be that bad if done properly.

Even if you get a short, firstly check that on the ends there are no strands of the braid touching the core if all good there, have a very close look at the cable to see if there are/were any kinks in the cable. Coax cable really doesn't like being kinked, it can damage the dielectric material between the braid and the core and lead to shorts, but if there was a kink somewhere normally it is quite obvious and leaves some marks on the cable.

Finding a short is sadly not always easy, there are some ways to get rid of shorts, but they tend to be on the dangerous side, if the cause of your short is not obvious it might be easier to just replace the cable. If you waste a couple of days finding a fault like this, it would have been much cheaper if you had just spent the R500 odd and get a new roll without issues

 

[Kylinho]

Sosio,

Thank you for the detail troubleshoot.

Will give it try in the next few days.

cheers

 

[The_Unbeliever]

so glad I'm over and done with coax cabling

was a nightmare to maintain back in the day... just one RJ45 connector coming loose, and the entire network's down...

But it worked quite well when it worked, was simple and quick to install, and was stable (except for when lightning struck).