Using RFL on a loaded pair

linepig · Fresh Face Joined: 08 Mar 2010 Posts: 3

Hi,
Being new to the cable repair trade....I just have a quick question. Can you use RFL to locate shorts & grounds on a pair that is loaded ? By this, I don't mean working between the load coils, but say strap at the C.O. then go to the far end of the leed.
Any answer are appreciated...

Dave72 · Posted: Mon Mar 08, 2010 4:21 pm Post subject:

I seem to recall seeing some example where you could do that, but you had to add some length equivalent for each coil. Sorry, dont have my books at hand to say exactly how much.

Jim Weston · Member Joined: 19 Oct 2009 Posts: 13 Location: NEBRASKA

Hi,
You didn't indicate what loads were in question so I'll assume your plant is H88 loading. As a rule an H88 load will add around 4.5 ohms to the distance reading. This relates to about 150 feet. So with that in mind if your RFL indicates a fault at 14kf you would need to subtract 300 feet from that distance. I'm also not sure of what meter you are using; however most meters require you to indicate at least 2 accurate elements in your meter's RFL "setup". These are: cable guage, temperature of the cable and length.
Hope this helps
jw

linepig · Fresh Face Joined: 08 Mar 2010 Posts: 3

Thanks Jim And Dave72,
I appereciate the responses... and Jim you are right the coil are H88 and I use a Dynatel 965 AMS.

Jim Weston · Member Joined: 19 Oct 2009 Posts: 13 Location: NEBRASKA

The 965AMS is what I use also. I don't know if you have ever been on the 3M web site but they have a training section that you can select and view training of the different tests that the 965 can run. I use this site often for review.
thanks
jw