View Full Version : explain the science if you can!!!!
yahoo
September 23rd, 2008, 11:48 PM
you hook the red lead to a main cable that is completely unbonded and the black lead to a ground about a foot away and then taking the reciever walk about 20 foot over and you find your signal....very good! lets say you take that same red lead hook to the cable then take the black lead and hook to the same cable what happens the signal goes nowhere!!!! ok here is the question.................you take the red lead and hook to a hot pair in that same cable that is still bonded to the ground...........and take the black lead and hook to the same ground cable that the red hot pair is hooked to and walk 20 foot over and now you have a signal same place......how is this possible????????????????
Dave72
September 24th, 2008, 12:15 AM
So the circuit is between the one line wire and the earth/shield.. I would think you would get enough signal spillout to pick it up.. Id guess the level would be noticeably lower.
We do sort of the same thing for pair fault finding in the old lead sheathed cables.. pull the CO and the customer offa the line, then put 600v on it to weld the trouble into a good short.. then put a 512hz signal across the pair. Using an inductive antenna on a stick basically, you can walk the line right to the trouble (the signal stops at the short.. the end of the circuit we welded).
The signal still comes out thru the bonded and grounded sheath.
TBONE
September 24th, 2008, 03:01 AM
What is happening is you are not creating the loop of the magnetic field if you have poor ground you can also if you have mulpiple cables or and in and an out hook the red to one cable and the black to another cable and push the signal in both directions [ learned that from Big Rob :) ] that works good if you have a test station with two access wires in it just hook to both and it will run both directions while using the other side as a ground.:cool2: but this is a last ditch effort and can get you in trouble :scold:
bareclaw
September 24th, 2008, 03:27 PM
What is happening is you are not creating the loop of the magnetic field if you have poor ground you can also if you have mulpiple cables or and in and an out hook the red to one cable and the black to another cable and push the signal in both directions [ learned that from Big Rob :) ] that works good if you have a test station with two access wires in it just hook to both and it will run both directions while using the other side as a ground.:cool2: but this is a last ditch effort and can get you in trouble :scold:
How can that get you into trouble, I've been locating that way for years it's the best possible ground you can get. You can locate for miles each way like that
TBONE
September 24th, 2008, 11:19 PM
How can that get you into trouble, I've been locating that way for years it's the best possible ground you can get. You can locate for miles each way like that
what I was refering to was using an abandoned cable on the other side Yes both active cables will run very well but you can use an abandoned cable as a ground in a must need situation but you can bleed onto the other cable
bareclaw
September 25th, 2008, 05:31 PM
Right on brother, hope I didn't piss you off by questioning you.
yahoo
September 26th, 2008, 12:39 AM
hey bareclaw thanks for your input dude...don't worry about anything you said t bone is no rookie to the forum.....he deals with all sorts of answers .......
TBONE
September 26th, 2008, 03:18 AM
Right on brother, hope I didn't piss you off by questioning you.
don't sweat it bro it is cool
Wingfoot
October 3rd, 2008, 03:55 AM
Take red lead - hook [it] to the cable - then take the black lead and hook to the same cable - the signal goes nowhere!!!!
You lost me at "Hello!" You have a dead short. No signal because there is no 'ground path return.' The signal stops at the hookup point.
ok here is the question.................you take the red lead and hook to a hot pair in that same cable that is still bonded to the ground...........and take the black lead and hook to the same ground cable that the red hot pair is hooked to - walk 20 foot over and now you have a signal - how is this possible????????????????
Let's see.......... You're hooking up tip-side on one of the pairs inside the cable you're trying to tone. And you are using the outer sheath of that cable as a ground. And it tones......... WoW! I've never thought to use this technique. Theoretically, I just can't imagine this technique really working. I could never walk away from a locate feeling confident of my marks using this technique.........
I encounter situations inside bank basements and a college recreation center where the telephone terminal has no ground available for my black lead. I get a small cup of water from the drinking fountain and pour a small puddle of water on the concrete floor under the telephone terminal. I let the water soak into the concrete for just a little bit. I place my black lead in the puddle of water to get my ground! My transmitter gets continuity and I get a beautiful tone on the cable outside.
Many times to get a ground in basement terminals, I stick my screwdriver in the ground receiver in a 3-prong electrical receptacle and clip onto the screwdriver for a ground.
sprayandpray
October 3rd, 2008, 12:06 PM
And you are still with us- Amazing! :D Can you imagine one of the USIC Safety Gurus seeing this bit of improvisation? They would crap their pants:hammer:
Goldenboy
October 3rd, 2008, 12:15 PM
Many times to get a ground in basement terminals, I stick my screwdriver in the ground receiver in a 3-prong electrical receptacle and clip onto the screwdriver for a ground.
Remember when doing this you will be using the electric service as your ground. If the telephone and electric run close to each other this would make for a damage. I use outlets all the time to locate electric but to use it as your ground when your hooking up to a different utility would scare me.
The ground in a three prong outlet goes right to the breaker box and is attatched to the neutral block. The nuetral for the electric service is attatched to the nuetral block. It's just my opinion your asking for a disaster using this as your ground because
Wingfoot
October 3rd, 2008, 12:58 PM
Remember when doing this you will be using the electric service as your ground. If the telephone and electric run close to each other this would make for a damage. I use outlets all the time to locate electric but to use it as your ground when your hooking up to a different utility would scare me.
The ground in a three prong outlet goes right to the breaker box and is attatched to the neutral block. The nuetral for the electric service is attatched to the nuetral block. It's just my opinion your asking for a disaster using this as your ground because
I totally agree. I mark both power & telephone. I have the advantage to know the pathway of both utilities when I improvise for grounding.
As a side note in grounding - Our transmitters are DC current - It doesn't matter if you use the red lead or black lead for a ground. I have leads with 2 styles of clamps - Big clamp on my black lead for grabbing the ground rod or cables that have the sheath exposed for toning. Small telephone clamp for delicate hook-ups. Using either lead for a ground will tone the utility.
yahoo
October 4th, 2008, 02:14 AM
thanks for the input guys!!!!!!!!!!!!
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