by Anthony Johnstone, Access Detection

A new range of high quality utility-locating equipment has hit the market, all offering impressive features which make locating easy. But does it make locating more accurate, or does it make the operator a better locator? You might be surprised by the answer.

New locators recently launched to the market include the new Rycom Pathfinder Professional, the RD 8100 and the UT9000/Utili-Guard.

Let’s start with the new functions. All these new units have new multi-function modes which give the operator little control over the instrument, such as automatic depth, automatic gain and cable directional indicators.

How do these functions work? Most use a combination of antennas in the receiver which guide the operator to the location of the pipe.

In most simple locates, they are just as accurate as the standard peak and null modes professionals would use.

But if there is any change to the quality of the magnetic field – for example, it becomes distorted due to influences from other services – these modes can become far less accurate.

For example, one locator forces you to rotate the receiver until an indicator lines up before it will give you depth.

The antenna that uses this function is influenced by the same distortion that can affect the other antennas in your locator, so the operator thinks the service is going in a different direction, when it is actually field distortion creating the error.

This is just one example of locators becoming more sophisticated, and trying to make a locator’s job easier – but in fact creating a false sense of accuracy.

My next word of caution regards the use of combined peak and null modes. These modes normally give the operator more control with the machine, and in some cases, can give an operator with good experience a clear indication if there is field distortion without having to switch between the two standard modes.

The reality of this combined peak and null mode is that operators will often focus on the left right guidance arrows normally associated with this mode.

The left and right guidance heavily uses the null or vertical antenna, which is susceptible to more field distortion than the peak antennas.

In a lot of cases, the operator uses this mode thinking it is more accurate when again it can ultimately create the same issue as the other multi modes. If you’ve ever used these modes on a weak signal, you’ll know that they can flicker and change, resulting in false readings.

Don’t believe the hype

Another good example of marketing hype is inbuilt GPS systems on locators. None of these systems are good enough to use for any kind of mapping due to them being sub 3m accuracy.

To do any kind of mapping you need sub decimetre accuracy usually associated with a separate RTK based GPS system in a clear environment, even then the GPS unit needs to be in line with the blade of your receiver to get the accuracy required.

The only function that current inbuilt GPS units should serve is the use of on-board logging, this allows you to track the general location of an operator and some systems even allow logging of data and functions of the machine.

So, what functions are worthwhile? It depends on what you regularly locate. If locating in congested areas I would suggest a unit which works well on low frequencies and possibly some kind of target direction mode (although you need to use these on well-earthed low resistant services).

Another handy tool is receiver-to-transmitter communication. This allows the user to select a frequency or up the power of the transmitter from the receiver.

This is handy if you are a couple of hundred metres away from your transmitter and wish to do this. Having an accessory port also may come in handy and makes the unit more flexible.

Most suppliers do little training when selling a machine, and in a lot of cases the person selling the machine knows little about how it operates or does not want to spend the time with the operator.

If purchasing sophisticated locator, there should be a minimum of at least four hours of training provided. As a trainer, I have seen many examples of operators who have been sold an expensive locator, only to be shown the basics of the machine and advised that these simplistic modes are all that is required to perform an accurate locate.

This is far from the truth and this is where dangerous mistakes or incorrect markings occur.

My suggestion is when you trial these units, do it in a more difficult area so you see how the machine performs with these dirty signals.

Don’t always believe the sales person trying to sell you the instrument, and ensure you have a good understanding of the technology before paying a fortune for a locator with lots of functions you may never need.

Remember to buy from a reputable company that specialises in this area, ensure you get adequate training after the purchase and be sure that the instrument can be serviced at an authorised service centre.

This partner content is brought to you by Access Detection. For more information, visit www.accessdetection.com.au.

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