question on finding coax

[cruzin]

I have a need to identify a coax. I have 5 coax running through my house and out the basement wall and can not pull any of them out as they are buried in the wall.
I have a access to them in only one area of the house in the ceiling of a basement closet. I need to find the one that is from my living room and cut it and use it for my gbox. Does anyone know of a way I can identify the coax. Maybe using a amp clamp meter or some other way. I can get to both ends but can not tell which of the 5 coax it is running in the basement. Silly question but I hope someone has a solution.

 

[Morbius]

Disconnect all of them except the one you want to find and have that one hooked up to the box and go to the other ends with a meter and check for DC voltage.

 

[mikelib]

I usally connect a nine volt battery at one end and use a volt meter at the other. Or borrow a cable tracer.

 

[cruzin]

I have the ends of them labeled it is in the middle, inside the house I need to figure out which one is which. I have a group of 5 running down a beam and dont know which is which. I wonder if I disconnect the inside and out and put a load on the center conductor of some sort and use a ohm meter in the middle where it is located in the ceiling of that closet. think that would work?

 

[brentb636]

A known load would work or simply shorting the shield to the center conductor and testing with an Ohm meter. Another method is to put an audible freqency on the shield and use a detector to isolate the cable. Here's one link , hxxp://www.techtoolsupply.com/index.asp?PageAction=VIEWPROD&ProdID=2089

 

[Morbius]

Any chance they are different brands or have any type of manufacturer markings on them? Last but not lease you can do the cut and splice method which no one wants to do.

 

[cruzin]

I have an Ohm meter but I have always found that when you have both hot and common within the ohm clamp it does not show ohms. maybe I can run a second wire for the common and run it from the shield on the floor out the window for my second wire that way only the hot will be on the coax. I will have to cut and splice but I do not want to do it till I find the exact wire to cut and splice.
Thanks for all the suggestions.

 

[cruzin]

A known load would work or simply shorting the shield to the center conductor and testing with an Ohm meter. Another method is to put an audible freqency on the shield and use a detector to isolate the cable. Here's one link , hxxp://www.techtoolsupply.com/index.asp?PageAction=VIEWPROD&ProdID=2089

Much to expensive! thanks

 

[cruzin]

Any chance they are different brands or have any type of manufacturer markings on them? Last but not lease you can do the cut and splice method which no one wants to do.

No chance, I bought a 500' box of the same coax when I ran those runs.

 

[Larry1]

Your cable may have foot markings on it which will help in determining what cable is what.

 

[jags1]

Here's an idea. Expose the shield at one end of the cable you want to identify. Connect it to a long length of any sort of wire (telephone, cat5, etc.) run that wire to the point where you need to make the identification. Take a needle or pin and stick it into one of the rg6 so that the needle makes contact with the shield. Take your VOM and see if you got a loop. If not stick a pin in the next rg6 cable and try again. You should be able to find your cable this way and the small pin hole will not cause any harm to the cable.

Good luck!!!

 

[mikelib]

Here's an idea. Expose the shield at one end of the cable you want to identify. Connect it to a long length of any sort of wire (telephone, cat5, etc.) run that wire to the point where you need to make the identification. Take a needle or pin and stick it into one of the rg6 so that the needle makes contact with the shield. Take your VOM and see if you got a loop. If not stick a pin in the next rg6 cable and try again. You should be able to find your cable this way and the small pin hole will not cause any harm to the cable.

Good luck!!!

If you have a good ground near the begaining of the cable you can use the nine volt battery and put + on the shield and - on to ground. when you use the needle with the pin you put the + probe to shield and the - to ground. I used this method when I worked for the phone company.

good luck from me too

 

[Splicer]

Simple...Just get a resistor with a known value and connect one end to the shield and the other end to the center conductor...Go to the other end of the coax and read the ohms untill yo get the right line...Simple fast cheap and easy...A pack of 5 resistors costs about 50 cents at Radio Shack...

Works every time...

 

[jags1]

You guys are making it it all harder than it actually is. First of all Cruzin is not trying to find the other end of the cable. He is tryinging to find the cable at a mid point of the run with 4 other cables. So splicer, brentb3636, mikelib, and morbius are all on the wrong track. Second you don't need to apply any type of load, voltage, or signal to the line. Again here is what you do:

Connect a long wire from the shield at one end of the run. Bring the other end of this wire to the mid point where you need to identify which of the 5 cables is the "one". Take a pin and pierce one of the five cables outer jacket till you make contact with the shield of the cable. Take your volt ohm meter and do a resistance or "circuit" check between the pin and the wire. If you have "stuck" the right cable you will have a closed circuit from the pin to the shield, to the end of the cable, to the wire you attached to the end of the cable, back to the end of your long wire. The volt ohm meter wll show this as a closed circuit. If you don't have a closed circuit you have "stuck" the wrong cable and you will need to try another. It's very simple and elementary!

You can use any kind of wire for the test. Even a long electric extension cord would work. If the cable has a "f" connector at the end, simply wrap the exposed end of your long wire around it. Or take an alligator clip and clip them together. Also you may not even need to use a pin to pierce the cable as most volt ohm probes are already quite "pointy" and may be able to pierce through the jacket to the shield.

It's simple guys!! Cruzin, if you stll don't understand what I'm saying let me know and I will post a "drawing" of this technique.

And again Good Luck!!!

Eric

 

[jags1]

Hey cruzin, I just noticed that you are already on the right track when you wrote:

maybe I can run a second wire for the common and run it from the shield on the floor out the window for my second wire .

Just connect that wire to the shield at one end and use the "pin" trick of sticking the cable at your mid point to make contact with the shield. Then use your volt ohm meter to test for a closed circuit. No need to cut the cable!

Good Luck my friend!!

Eric

 

[brentb636]

Hey cruzin, I just noticed that you are already on the right track when you wrote:



Just connect that wire to the shield at one end and use the "pin" trick of sticking the cable at your mid point to make contact with the shield. Then use your volt ohm meter to test for a closed circuit. No need to cut the cable!

Good Luck my friend!!

Eric

Make sure you disconnect all the cables at both ends, so you don't have the shields tied together or to ground, otherwise you'll have spurious results, and end up cutting the wrong cable, anyway. Isolate all the cables from each other , and ground, and this should work fine.

 

[jags1]

Make sure you disconnect all the cables at both ends, so you don't have the shields tied together or to ground, otherwise you'll have spurious results, and end up cutting the wrong cable, anyway. Isolate all the cables from each other , and ground, and this should work fine.

That's right Brent!! Thanks for making the point of having all the cables disconnected. That is important!

Cruzin, Let us know when you get it done!!

Eric

 

[Splicer]

I have the ends of them labeled it is in the middle, inside the house I need to figure out which one is which. I have a group of 5 running down a beam and dont know which is which. I wonder if I disconnect the inside and out and put a load on the center conductor of some sort and use a ohm meter in the middle where it is located in the ceiling of that closet. think that would work?

No chance, I bought a 500' box of the same coax when I ran those runs.

Your cable may have foot markings on it which will help in determining what cable is what.

Larry 1 has told you how to then...Just look at the footage marks...No pin sticking no resistor no wire out the window...Use the footage markings to your advantage...Or cut them all and barrel splice the ones you don't need back together...Personally I would use the footage markings...

 

[cruzin]

Wow thanks for all the ideas folks. I will have to remove the face plate on the desired cable as when I built this place I ran the cables up to a box then connected the coax to the back of the box cover that I plug another coax into to run to stb. If there is not any foot markings visible on coax I will have to use the pin prick method.
I may not get at it till this weekend as work has me gone alot this week. thanks again. I will post results.

 

[Sadoun]

Here is what you need to use:



The Coax Cable Continuity Tester is an easy to use tool for testing coax cable. With it you can check DC shorts, splitters and self-grounding devices in coax cable. An audible tone sounds when the line-carrying signal is detected.

Don't spend hours trying to figure out which coax cable goes to which jack. Save time during wiring projects with this pocket-sized Pocket Toner continuity tester. After completing the pre-wiring stage of an installation, you could be faced with dozens of coax cables. While it is easy to group the different cables, you still have to figure out which cable goes to which jack or location. The Pocket Toner can help you solve this problem in minutes.

Simply plug the sender into a wall jack in a room. Back at the location where all the cables come together, connect one cable at a time to the speaker until a tone is heard, and you've found your cable.

Specifications:

Specifically designed for RF cable applications
Easy-to-store toner stores in base for easy access
Right angled, male push-on connector for fast use female toner connector is also a quick-connect design
Dual female F-connector (included)
12 Volt 23A battery (included)
Measures 4-1/8" x 1" x 3/8"