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navitrack v sr20

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  • navitrack v sr20

    I think I've done my research pretty well, so hopefully this is a good Q. about to buy locator. since the navitrack and the sr20 are identical in price, is there some advantage to the navitrack over the sr20, or is the sr the way to go? it will primarily be used to locate sonde, but the reason i might get the navitrack or sr20 is that i might do some copper locates under slabs. Any thoughts on navitrack vs. sr20? thanks!

  • #2
    Re: navitrack v sr20

    Originally posted by buyfield View Post
    since the navitrack and the sr20 are identical in price, is there some advantage to the navitrack over the sr20, or is the sr the way to go?
    The SR-20 and NaviTrack II have the same sonde locating interface, and either instrument would give you an excellent result for your specific line locating application.

    If you're doing a lot of line tracing, the SR-20's extra line locating capabilities can make each job a bit faster. But if you want to retain maximum flexibility, then the NaviTrack II with its higher frequency range would be a good choice.

    Guy

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    • #3
      Re: navitrack v sr20

      Thanks Guy very much. If I might lean on you a bit more, if you get a chance, perhaps you could elaborate a bit on what the greater flexibility over the sr20 is exactly--that is, what the greater frequency range would help with. Thanks

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      • #4
        Re: navitrack v sr20

        Alternating current flowing through a circuit produces a signal that can be detected, or located, above ground with a receiver. To get current to flow you need a complete, or closed, circuit.

        So line locating is all about creating a circuit such that current flows on your target conductor (the utility you're trying to trace). Unfortunately, current is lazy, always taking the path of least resistance, which can sometimes make it difficult to get a usable signal on the line you're trying to trace.

        In some cases you may be faced with a high impedance circuit - metal gas lines have insulators at the joints, for example - that raise the impedance of the circuit. Using a higher frequency can help overcome the resistance of a high impedance circuit so that current can flow on the line - 8kHz or 33khz will usually be enough to get current flowing.

        In other situations you may be trying to get current to flow on a conductor that isn't well grounded, and that may require you to use an even higher frequency that's beyond the range of the SR-20 (the NaviTrack II can handle frequencies as high as 262kHz).

        But there also also situations where the SR-20 really shines....

        In some instances you may be faced with current flowing on an adjacent conductor. In the case of your water lines, this could happen when other utilities use the water line as a ground. In cases like this, the signal on an adjacent utility may interfere with the signal on the line you're trying to trace. The SR-20's extra set of antennas and related on-screen indicator make it easier to see when this is happening so that you can try to create a better circuit.

        Each of the tools that you're considering has its advantages. Of course, you could always purchase the SR-60 and get: d) All of the above!

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        • #5
          Re: navitrack v sr20

          the voice of ridgid even walks the walk

          for those that don't know guy, you all know his voice

          turn on your locators and that's guy

          rick.
          phoebe it is

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          • #6
            Re: navitrack v sr20

            Thanks Guy. Extremely helpful. Which leaves the only decision to be Scout vs. sr60, since by the time you buy the transmitter, the difference in price between the 20 and the 60 is fairly minimal.

            Ground here (slabs) is pretty much always attached to cold at water heater--if tracing water line under slab, would you unhook ground or just let the sr60 work its magic?

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            • #7
              Re: navitrack v sr20

              Originally posted by buyfield View Post
              Ground here (slabs) is pretty much always attached to cold at water heater--if tracing water line under slab, would you unhook ground or just let the sr60 work its magic?
              The SR-60 has some serious magic, but in terms of tracing a utility the real magic is creating a good circuit. A "good" circuit is one where current flows on the target conductor - and ONLY the target conductor.

              Always remember that when you are "tracing a line" you are actually tracing a signal and making the assumption that the signal is emanating from the line that you connected your transmitter to. Unfortunately that is not always true. Here's something I personally experienced during a two-day training seminar:

              Our class connected the line transmitter to the tracing wire for a poly gas line and began tracing it. One way to make sure you're tracing the correct utility is to follow it all the way to its logical termination point, which we did. Or so we thought...

              At one point the line made a turn... and led us straight to a water valve. Our instructor explained that this happens at this particular location - but only when the ground is saturated with water. His explanation: there was likely a nick in the tracing wire's insulation, and when the earth was wet the signal transferred to the nearby water line because that offered an easier path to ground.

              We had at least 10 different locators with us and none of them were able to trace a line with no signal on it - that magic doesn't exist yet! So to answer your question, if it is safe to do so, unbonding a common ground will eliminate one unintended signal path.

              I mentioned earlier that the SR-60 has some serious magic. The feature I had in mind is called OmniSeek. It's a passive locating mode that will let you find and trace lines without energizing the target conductor with your transmitter. It works by detecting RF energy generated by TV/Radio stations, electrical equipment, and power lines. The "magic" is that you don't need to try and tune it to a specific frequency. Instead, the receiver looks for repeating patterns of energy and locks on to them. It's really quite stunning. (The SR-20 has this feature as well).

              It's considered "Best Practice" to energize a line with your transmitter. But OmniSeek is a great tool for doing blind sweeps of an area as a final check before digging. It's also a great tool for finding a water valve hidden by bushes so that you can connect your transmitter to it. This feature is covered about 21 minutes into the SR-60 training video: http://www.ridgid.com/Tools/SeekTech...2/EN/index.htm

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