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Thread: Why can't you find it?

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    Mke
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    Default Why can't you find it?

    So, I'm tired of hearing that, and want to bounce this off the board so I can see what you guys think, or what suggestions you guys have.

    Level 3 has a fiber line near a rail line (running parallel to each other). We are currently working with the city to place a 48" steel casing under the rail lines. In order to do so, we need to positively identify the Level 3 fiber and document the I.E. to verify that the casing will miss the fiber.

    The first attempt was based on the Level 3 locators mark and it was 4' off of where I recieved the mark. The line is down about 14' or so deep. The second attempt by the Level 3 guys put the mark about 2' off of where I recieved it. On the 3rd attempt, the level 3 guys decided to work with me and we put an 810, 850, Vloc Pro, and an Rd 400 on it as well as a DigiTrak Mark 3 with sonde and recieved the signal all within about 6'' of each other.


    We dug down and found jack squat. The water table is at about 11' so it clouds the bottom of the pot hole, and we have to use a pvc casing so not to undermine the track bed. Doing this prevents any "fanning out" of the pothole.


    My engineers are looking at me and wondering if there is anything else we can do.

    The only thing that I can think of is that the casing is going down at a slight angle and we are missing the Fiber by inches.

    Do you guys have any other suggestions on what to use in this situation?


    Just curious, if you need any additional information, just let me know.

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    Member KaineF's Avatar
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    Default Re: Why can't you find it?

    whats the max depth that those trans and receivers work at? i know some cant go very far and maybe putting you off of the fiber. Just throwing that out there

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    Premium Member daman1's Avatar
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    Default Re: Why can't you find it?

    I'm not sure what the max depth is for receivers is but I know the deeper you get the wider the signal field is before it reaches the receiver. If you can imagine it in a graphic, the signal spreads after it leaves the tracer in all directions. The further you are away from it, the more the center of the signal can be off. I hate locating things that deep. Anything more than about 5 ft down and it gets hard to pinpoint.
    I'm sure it's somewhere inside the marks. You just don't know which way to dig so it may as well be on the moon. If you can get yourself or even just lower your receiver down into the pothole in "null" mode, it should start to zero in better as you get closer and give you a clue which way to dig. I've been able to help the pot-holers out that way before. It saved them allot of work.
    Just a theory here but..... Could the water be messing with the signal too? It sounds submerged 3 ft down into the water table if I read you right. I don't know how much impact that would have on a signal though. Water could be a path of least resistance and draw it off. Especially if there's any direct water contact with an exposed section of tracer.
    Last edited by daman1; April 18th, 2012 at 08:43 PM.

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    Senior Member ProfessionalLocator's Avatar
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    Default Re: Why can't you find it?

    I find once you get the ground saturated with water the signals go all to heck.

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    Conservative Meanie ifinditunderground's Avatar
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    Default Re: Why can't you find it?

    MKE, I would have my guys get a solid hookup at a medium to low frequency first. Second, I would have them get a good spotlight and a long rod, 16 to 20 feet in length. And a very bright spot light as well. Duct tape your receiver to your rod, and lower the receiver into the hole watching your current numbers and directional guidance. If the numbers increase, you are on the right track. If they stay flat or go down, you are digging in the wrong place. It sounds like you are close though. The closer you get to your utility the more accurate your guidance readout will be. Fingers crossed it is in the center of your casing, or at least within your casing pipe. If it is, awesome, keep going, if not, pull your casing and start over in the right place based on the guidance from your receiver down in your hole. Get that receiver as deep as you can get it. Hence the bright spotlight. I would tell my guys, if the receiver says it's within your casing, keep digging until someone is looking back at you. Good luck, and if you need more details, pm me for my cell number and we can chat on the phone. And NO, ground water has no real effect on EM signals. Depth will play more of a factor here.
    Last edited by ifinditunderground; April 18th, 2012 at 09:43 PM.
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    Senior Member Wingfoot's Avatar
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    Default Re: Why can't you find it?

    MKE - I have a G2 Digital Verifier to use in the situation you have described. It has worked well for me when everything else has failed.

    Verifier G2 Digital Locator - Mitchell Instrument Company

    -----------------------------------------------

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    Mke
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    Default Re: Why can't you find it?

    Thanks for the input. Even though it is not my utility, my balls are in a vise on this one. I have my engineers breathing down my neck asking why we havn't found it in 3 attempts. It sounds like excuses, but I wasn't involved in the locating on the first two attempts.

    I'm right there with you Ifindit, its the depth that is really F'ing with the locate. I still stand behind Bessy's (My 810) marks. I know 14 is topping out on the reach of the 810, and the needle movement was very slow, but it was still markable. I think, if we get the go ahead on another attempt, i'm going to lower my reciever into the casing. The horrible part is that the Hand Holes for the fiber are covered by 3'-4' of gravel and it almost takes an act of congress to get them to open it.

    I unfortunatley don't have a locator with variable frequencies, so i'm handcuffed to what the Level 3 locators have. One has an Old RD400 and the other has a VLoc Pro. Neither of them use the transmitters. The RD doesn't even have direct connects or a ring clamp. The Level 3 guy thinks his transmitter is at the office, but isn't sure.

    I think we are going to do a 4th attempt. With this attempt, I plan on lowering the reciever into the PVC casing to see if we can pick up the signal strength and narrow down the location. I don't know how much wiggle room an 18" casing is going to give the reciever to move around in.

    The attatched picture is of the site. You can see the 3 pothole locations. At Each site the pot hole consists of an outer casing that goes down about 6' and is a larger diamter then the inner casing. The inner casing is an 18" dia PVC about 10' long. and its telescoping out of the upper casing. So both visable casings are larger then the actual pothole.

    As for the G2 wing, No one wanted to pay to pot hole this thing in design, i'm pretty sure they don't want to pay 4k for a piece of equipment that may or may not find it (In their eyes of course).

    As for the range of the recievers.... my 810 goes up to about 15' and a little past, but not much and only in uncongested areas. The 850 is about the same. You guys would probably know better about the RD400 and the Vloc.



    Do you guys think its better to push a rodder with tracer wire into the pipe for a better conductor, use a Sonde, or trace it by the frequency that is put on the fiber from God knows where by level 3?

    I'm teetering on the sonde and tracer wire if Level 3 lets us into their handhole.

    Thanks.

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    Conservative Meanie ifinditunderground's Avatar
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    Default Re: Why can't you find it?

    I say go with the tracer wire. Try to go all the way between two handholes if at all possible, and ground the end you are not hooked to. This should alleviate the locating concerns, the rest is just hard labor and persistence.
    There is a fine line between "Hobby" and "Mental Illness."
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    Premium Member daman1's Avatar
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    Default Re: Why can't you find it?

    Oooh I just hate it when engineers think they understand locating better than a locator. He's just busting your balls. At that depth, it would give anyone a problem.
    It doesn't sound like you have the equipment available either. I know how bitching about your equipment sounds to engineers. They think it's like a golf pro blaming his clubs. Tell them to try it for a week or two. 810's are great but if it's an old needle meter, you don't have frequency options or null mode. I know RD400's do. They don't pick up the 810's frequency though so you'll need the transmitter too.
    I fear that the signal is running fine and rodding a tracer would be redundant. The deepest line I've ever marked that I got to see exposed was 11ft down. I went slow and marked it coming and going from two different access points and I was off by nearly two feet. I was able to get down in the hole and use the null arrows to tell them which way to search.
    Allot of companies are burying things that deep because it seems safest but it comes back to haunt them if they ever need to find it again. They're very hard to locate and expensive to dig up. Engineers don't always know that.
    Last edited by daman1; April 19th, 2012 at 05:24 PM.

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    Senior Member Bad Robot's Avatar
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    Default Re: Why can't you find it?

    I'm with I Find It on this one, go for the tracer with a solid ground on the out end. Barring that, I would suggest running it out with that Vloc rig if available, and following his advice in lowering the receiver. The Vloc does a great job in tight spaces compared to the 810. Good Luck friend!

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    Mke
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    Default Re: Why can't you find it?

    So, We had another meet on site yesterday. Had the RR guys there, our engineers, Inspectors, and a hand full of level 3 guys. I asked them about pulling a 5pr tracer through a spare, they told me that the next Hand Hole to the south is about ..... 1000' away and under compacted gravel, so they think the pulling a tracer all the way through is out of the question.

    The meeting became a pissing contest between level 3 and the contractor. The contractor appears to have read the law book just enough to throw out that he has contacted the PUC to complain about level 3's ability to find their plant.

    Instead of potholing a 4th time where we recieved a signal previously, they want to step the holes from where its shallower to deepest. I think this is a waste of money because all it does is show where the cable is nowhere near the proposed crossing.

    They are still going to have the same issues when they get closer to the proposed crossing. Either way, I'll be out there all "F"ing day again.

    I believe that the Level 3 tech is going to bring the transmitter for the Vloc today, and i'll have our contractor with his RD4k as well. More the merrier.

    mke

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    Senior Member UTILQ1's Avatar
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    Default Re: Why can't you find it?



    We pay you to find the damn lines !!!

    If you can't than you know the deal....

    Here- Oshkosh Post Hole Diggers


    If you need the 2051-14's to get the job done than request them!!! Just git er done...


    use the designated potholing equipment start from the source working your way out... case closed NEXT!!!





    hee hee hee

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    Member Jcbro86's Avatar
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    Default Re: Why can't you find it?

    i know that i have no stake in this whatsoever, but if i was the level 3 locator, i would paint that fiber wide as all get out and let the contractor pothole it or run the risk of hitting it under my huge paint mark since they are starting to complain about the inability of the locator. of course i would have already extinguished all options and elevated it to at least my supervisor, but if i still had to paint the line and it was my butt at stake, thats how i would do it.

    as far as trying to find this fiber is concerned, is it in innerducting or conduit? if so maybe it could be potholed at 2 known locations that are not so deep on either side. the innerducting could then be split for a wire, or line could be ran between the good potholes like when you line up a fence with string as another way of finding a good pothole spot.

    in situations like this that i have been in, i had to be there on the day of excavation. hook up and give them scoop by scoop info on depth until it was finally within range for me to give them some good information, then they actually found it and everyone was happy. i had to mark a fiber and a 25pr that went under a new highway in my area, the lines were lowered to 25+ feet, which i learned after speaking with the designing engineer. i could locate it on either side but not thru the middle of the new area because it was so deep. the contractor had me out there one day and said he had to make a 10 foot cut on each side. i hooked up and told him i was still maxed out on depth after he took out 5 feet, then 8, then the full 10 and i was still maxed out. luckily this was just a crossing and not parallel to the highway, that would have sucked alot worse.
    "You can never trust AT&T to do the intelligent thing..." - SM&P Lead Tech

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    Default Re: Why can't you find it?

    Come on Man! I get this is a very difficult situation but you and the client need to find the line. Leaving it up to the excavator and marking it wide isn't the answer. Jointly is the only way this one is going to be worked out without damage to the facility or a ton of wasted time by the excavator.

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    Premium Member daman1's Avatar
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    Default Re: Why can't you find it?

    Sniper's right, I think you're gonna have to baby-sit this one. Be there during the excavation and help steer them towards the line as best you can. Sup's may not like you using up so many work hours on one ticket but the key is damage prevention so do what you gotta do. If they won't let you be there then you're off the hook.

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