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Thread: make shift clamp

  1. #1
    Member rockiesgirl's Avatar
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    Lightbulb make shift clamp

    If you are in a manhole and your clamp won' t fit around a bigger cable just wrap a flag around it, make a loop, and hang your clamp through it. This works great, sometimes you can even get a signal with your leads but not always. This also works well when there is a cable coming down a pole and there is no room to get the clamp around it.
    Work smarter not harder!!!

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    Conservative Meanie ifinditunderground's Avatar
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    Default Re: make shift clamp

    That is the first time I have heard of that. I will be giving it a try next change I get.
    There is a fine line between "Hobby" and "Mental Illness."
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    Member sundropmaster's Avatar
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    Default Re: make shift clamp

    Thank you for sharing that, did you figure this out on your on or..... ???

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    Member rockiesgirl's Avatar
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    Default Re: make shift clamp

    As we all know being innovative makes a good locator. I am always trying new things on locates because as we all know sometimes the tried and true doesn't always work or there are factors that hamper our efforts. I first tried this about 8 yrs ago when I was doing a locate where I had a 900 pr feeding down a pole and the riser was really high. I was standing on 2 boxes of paint (I carry a small ladder now) and needed another 4 inches to get to the cable. I just grabbed a flag, bent it and fished it around the cable, made a loop and put the clamp through it. WOOOWHO it worked. I just figured everyone knew this little trick. After all what is a clamp. A conductor trying to send a current onto another conductor. This works on gas risers, cable TV etc. Like I said when using your leads it doesn't always work, but has always worked with the clamp.
    Work smarter not harder!!!

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    Member sundropmaster's Avatar
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    Default Re: make shift clamp

    Quote Originally Posted by rockiesgirl View Post
    As we all know being innovative makes a good locator. I am always trying new things on locates because as we all know sometimes the tried and true doesn't always work or there are factors that hamper our efforts. I first tried this about 8 yrs ago when I was doing a locate where I had a 900 pr feeding down a pole and the riser was really high. I was standing on 2 boxes of paint (I carry a small ladder now) and needed another 4 inches to get to the cable. I just grabbed a flag, bent it and fished it around the cable, made a loop and put the clamp through it. WOOOWHO it worked. I just figured everyone knew this little trick. After all what is a clamp. A conductor trying to send a current onto another conductor. This works on gas risers, cable TV etc. Like I said when using your leads it doesn't always work, but has always worked with the clamp.
    Well I've never heard that little trick before, thanks again for sharing that :-)

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    4Q2
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    Default Re: make shift clamp

    Yes rgirl, I have used a version of this technique. I carry a 5' length of copper com wire with the ends stripped and wrap it around large conduits, etc to induce a signal. The more times you wrap it around the stronger the induced signal is. I have found it works with mixed results, so definetly a last resort.

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    Member sundropmaster's Avatar
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    Default Re: make shift clamp

    I tired that today and it worked great, thanks alot, that saves me some time and labor lol

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    Member GroundScope's Avatar
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    Default Re: make shift clamp

    Great Idea !! I tried it Too, works just as good with a single loop or a bunch of turns of wire coiled & joined. The current is less than the Clamp but all the same is something new I'll take with me !

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    Junior Member orangefoot's Avatar
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    Default Re: make shift clamp

    wow

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    Default Re: make shift clamp

    The technique of wrapping a cable around a utility is a very useful technique. Here in the UK we have difficulty locating the telephone or CATV feeds into properties because the end of the feed into the property is not earthed so it is difficult to get a signal to flow from the street to the house. If you connect the croc clip onto the cable (it doesn't have to be the metal part) and earth the black lead it is possible to get a signal onto the cable. The object is to get the red croc clip as close to the cable as possible as it does not have to touch so you could just clip it onto the plastic covering of the cable. This technique is known as capacitive coupling and is particularly useful when locating spurs to properties.
    The capacitive coupling technique can be used around streetlight columns, especially ones where you cannot direct connect or use the magnet. The more turns you wrap around the column the more signal will get onto the cable.
    You will find that the higher the frequency the better the coupling so I would recommend using something like 131kHz. Another important factor is the output voltage of the transmitter, the higher the output voltage the stronger the signal. I use a Radiodetection TX10 to do this technique which has 131kHz and the added benifit of up to 90V and works brilliantly.

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    Senior Member Enjoythefall's Avatar
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    Default Re: make shift clamp

    Quote Originally Posted by Doctor Locator View Post
    The technique of wrapping a cable around a utility is a very useful technique. Here in the UK we have difficulty locating the telephone or CATV feeds into properties because the end of the feed into the property is not earthed so it is difficult to get a signal to flow from the street to the house. If you connect the croc clip onto the cable (it doesn't have to be the metal part) and earth the black lead it is possible to get a signal onto the cable. The object is to get the red croc clip as close to the cable as possible as it does not have to touch so you could just clip it onto the plastic covering of the cable. This technique is known as capacitive coupling and is particularly useful when locating spurs to properties.
    The capacitive coupling technique can be used around streetlight columns, especially ones where you cannot direct connect or use the magnet. The more turns you wrap around the column the more signal will get onto the cable.
    You will find that the higher the frequency the better the coupling so I would recommend using something like 131kHz. Another important factor is the output voltage of the transmitter, the higher the output voltage the stronger the signal. I use a Radiodetection TX10 to do this technique which has 131kHz and the added benifit of up to 90V and works brilliantly.
    This information is not completely correct. The more winds around the target cable, the more resistance, and the more the signal dissipates before being induced onto the target facility. Same reason that if you're connecting to a slack loop you connect to the side of the loop in the direction you are tracing out. Think of how a transformer works, through induction. I have personally connected a croc clip to the non metallic portion of both phone and CATV cables, and unless you squeeze it to the point that the teeth of the croc clip cut through the plastic, and come into contact with the sheath, you get no signal.


    If there are no earth grounds at the house, then that is the place you should connect every time. You'll get the best signal if the line you're tracing is grounded on the other end. Ground path return and whatnot. I know that you can trace ungrounded cables, but I've had very little luck doing so with my rd 8000. 4000 was a beast, but I guess it all depends on the equipment.

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    Default Re: make shift clamp

    Quote Originally Posted by Enjoythefall View Post
    This information is not completely correct. The more winds around the target cable, the more resistance, and the more the signal dissipates before being induced onto the target facility. Same reason that if you're connecting to a slack loop you connect to the side of the loop in the direction you are tracing out. Think of how a transformer works, through induction. I have personally connected a croc clip to the non metallic portion of both phone and CATV cables, and unless you squeeze it to the point that the teeth of the croc clip cut through the plastic, and come into contact with the sheath, you get no signal.


    If there are no earth grounds at the house, then that is the place you should connect every time. You'll get the best signal if the line you're tracing is grounded on the other end. Ground path return and whatnot. I know that you can trace ungrounded cables, but I've had very little luck doing so with my rd 8000. 4000 was a beast, but I guess it all depends on the equipment.
    The technique I described above is known as capactive coupling and does in fact work very well. This technique is all about capacitive reactance and if you look at the formula you will see that if you increase the frequency or increase the amount of capacitance by putting more turms around the object the resultant reactance will fall and therefore you will get more signal coupling onto the cable.

    I agree that you should always try to apply your signal at the end where there is not a ground and what signal you get onto the utility will always flow to the place that offers least resistance. As mentioned, capactive coupling will work best using high frequency and high voltage but it will not outperform the practice of direct connection and this should be taken into account when comparing signal levels. Capactive coupling merely provides an alternative to direct connection especially if you have no access to the actual conductor.
    There is no reason why the RD4000 would outperform the RD8000 using the technique that I have described and this includes the repective transmitter being used.
    Please try the technique above and experiment using different frequencies, turns and voltage levels.

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    Default Re: make shift clamp

    Quote Originally Posted by Doctor Locator View Post
    The technique I described above is known as capactive coupling and does in fact work very well. This technique is all about capacitive reactance and if you look at the formula you will see that if you increase the frequency or increase the amount of capacitance by putting more turms around the object the resultant reactance will fall and therefore you will get more signal coupling onto the cable.

    I agree that you should always try to apply your signal at the end where there is not a ground and what signal you get onto the utility will always flow to the place that offers least resistance. As mentioned, capactive coupling will work best using high frequency and high voltage but it will not outperform the practice of direct connection and this should be taken into account when comparing signal levels. Capactive coupling merely provides an alternative to direct connection especially if you have no access to the actual conductor.
    There is no reason why the RD4000 would outperform the RD8000 using the technique that I have described and this includes the repective transmitter being used.
    Please try the technique above and experiment using different frequencies, turns and voltage levels.
    I agree.......resistance has little to do with inducing a signal (just turn up the wattage) than magnetic capacitance does and the more windings the more capacitance area. Thats the same reason why the better induction clamps have more windings.

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    Senior Member Enjoythefall's Avatar
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    Default Re: make shift clamp

    160px-stromwandler_zeichnung.svg.png

    Alright. Lets imagine that the red rod is the cable being clamped, and the wound ring is the signal clamp. You'll notice that the induction coils are wound so that the loops are running in the same direction as the cable. This is the most efficient way to induce a signal electromagnetically, as it lines EM field up with the target facility with a 0* offset. Wrapping a length of wire around the cable as described, you are trying to induce a signal by applying a 90* offset field to the target line. The only reason any signal is being induced at all is due to the imperfection of the "coil" you are creating with your length of wire. Instead of a 90* offset, in reality it could be any range of angles depending on how the wire is wrapped. The closer to 0* the stronger the signal, so you are eeking out something useful.


    Resistance does have very little to do with this, however it is important to take into account due to the limited wattage any transmitter in the US has. The induction frequencies are limited to 1W output by the FCC.

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    Administrator TheCableVine's Avatar
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    Default Re: make shift clamp

    Maybe wrapping the wire around the cable and then coupling onto the wire only serves to hold the coupler in very close proximity to the cable and thus an induction takes place. You don't have to clamp a cable to induce a signal into it I'm guessing. Try leaning the coupler against a cable and see if that works.

    I will try that tomorrow and see if I am correct.
    "Change does not always equal progress."

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