We reviewed a number of underground cable and service locators from Radiodetection, as one of the most common questions we are asked is what the main differences are between the different models. For the purposes of this review, we chose the CAT4+, which is the entry level model, the RD2000 Super CAT and the RD7000+ and RD8100. The RD7000+ and the RD8100 are precision locators.


Radiodetection are a market leading global company in the field of cable and services detection, and offer a wide range of products. We choose this brand, for a number of reasons, one of them being that they offer global support and service, including here in Australia. The other reason, is that we have just found them to be more versatile and better than many of the competitor products. Having the local back up and support gives peace of mind, and in the rare event of a problem, any potential downtime of the product is minimal.


CAT 4+

The CAT 4+ is Radiodetection’s entry level underground cable and pipe locator (CAT is an abbreviation of cable avoidance tool) and this is the 4th generation locator, although it is backwards compatible with the CAT 3 locator system, so for example the CAT 4+ genny will work with the CAT 3 locators, if it is ever required to. It’s a useful feature to have from a forward thinking perspective, because if Radiodetection replace the CAT 4+ in the future, you should still, in theory, be able to replace the parts which you need to replace rather than the whole kit. For example, if the locator needs replacing, you could just replace the locator and use it with the existing receiver, although we think the requirement to do this is limited.


Even for a so called “entry level” underground locator, the CAT 4+ still has plenty of features. We used the kit, which is a comprehensive enough set up for general location jobs, and this consists of a locator, signal generator (or transmitter), the leads, earth stake and induction clamp, all supplied in a bag with a calibration certificate, user manuals, USB cable and CAT Manager software.


The CAT 4+ we found extremely easy to set up and use. The locator (also called the receiver) is a nice, robust build quality with an easy to read display and is also very simple to operate, having just a trigger button, which needs to be held in whenever the user wants to have the locator switched on and in locate mode. The transmitter (or signal generator) is even easier to user, as there are only two buttons – one to turn it on and a signal boost button, which we will come to shortly.

There are no frequencies to select, and therefore you don’t need to have to understand different frequency selections with the CAT4+. Radiodetection have kept it as simple as possible, with just a single frequency of 33kHz, which is used for it’s ease of coupling on to services to make locates easer. However, with the CAT4+, Radiodetection have also added a specialised “small diameter” locate frequency, which is supposed to make location of small cables, such as those found in telecommunications and low voltage applications, such as irrigation systems easier. We tested it on some known phone cables and found that it was able to locate them with relative ease, although they were only located around 600mm deep. We were able to get a good strong signal and even display an accurate depth reading. The LCD display on the CAT4+ locator is simple and easy to read, with just a mode display in the top right hand side, and a signal bar graph in the middle to show the strength of the signal being received. Just below that is the depth button, which when pressed will show the depth of the buried service on the screen in metres. We tested it on a known power cable, and were easily able to get a depth reading of 0.45 m which when compared to the building plans was more or less exact. The depth reading on the CAT4+ will only work when the transmitter (signal generator) is connected. If using the CAT4+ without the transmitter in “Power” mode, a depth reading is not available.


The display is definitely not over complicated, and will suit those users who just want to know that there is something there, and where it is without the need to have more advanced information available.


There are a number of modes available on the CAT4+ and these are split into two types. Active modes are the ones where the signal generator (transmitter) is used to apply a signal to a buried cable or other service, and passive modes are the ones where the signal generator is not used. For live cables, the power mode, which is a passive mode can be used without the need to connect the signal generator. The magnetic field generated by the cable is picked up by the locator. We had Strike Alert on the CAT4+ which we were testing, and that function worked really well. With Strike Alert when the user is getting close to a live cable, the CAT4+ sounds an alarm and alerts the user to the impending danger. Genny mode is specifically for locates when the signal generator is attached to a live or dead cable, for using the induction clamp and allows depth to be displayed.


The signal clamp can be used on services where the end of the cable or pipe is not accessible, or where is cannot be disconnected. This is 100mm diameter, so should fit around most things.


In avoidance mode, which we used quite a bit, the locator uses a mixture of power, genny and radio modes for faster site surveying.


The signal generator output can be boosted by up to 10 times from the standard 0.1 watt to a 1 watt output. We tested this and did notice a tangible difference with the signal boost on, particularly with the accuracy of depth measurements. Radiodetection also say it aids with deeper and longer locates, but we didn’t test anything longer than 100 metres long. We were able to get down to over 2.5 metres in the ground though.


One of our favourite features of the CAT4+ is the eCert system, which allows the locator to be remotely calibrated by the user without using any special equipment. This can be done by using nothing more than the supplied USB cable, and CAT Manager software program. The user simply runs the program, and activates the eCert function. With the USB cable connected to a PC with internet connection, the locating circuitry is tested and checked against the original settings. On a successful conclusion of testing, which takes a matter of minutes, a Radiodetection calibration certificate can be saved and/or printed out. This function we really liked, not only because we have never seen it on anything else, but because it makes downtime and sending the unit away for calibration a thing of the past. There is a small cost involved to get the licence key, which is around half the cost of a traditional calibration, but having no inconvenience or downtime is worth it.


If you want to locate anything other than cables or conductive pipes and services, for example plastic pipe, then you will need to use a sonde, which is a small (some are bigger than others) radio transmitter which you attach to a reel or push rod and locate with the CAT4+ receiver. The reel or rods need to be attached to the signal generator (transmitter) and a signal applied. The one thing we didn’t like about the CAT4+, and to be fair, this can be said of any cable locator system we have ever seen, is the relatively high cost of the accessories. Most of them are not required for standard locates, so this does somewhat negate it.

The standard accessories are all supplied with the kit, and the connection leads are stowed away in the bottom half of the transmitter for convenience, which is a nice touch and keeps everything neat and tidy as well as safe.


Overall, we think that this is an excellent no frills service locator with some nice and easy to understand functions. There are always going to be some negatives, but with the CAT4+ these are few and far between. It offers good value for money, compared to the cost of other locators, and the enhanced functionality makes it a very useful piece of equipment.


What we liked Most:

Easy to use, everything included in the kit, eCert remote calibration, lots of functionality for the cost, local back up and support, reliable and robust.

What we didn’t like:

Accessories can be quite expensive, signal generator capped at 1 watt output (but still works well).


RD2000 Super CAT

The RD2000 Super CAT is Radiodetection’s next step up in underground cable and service locators from the CAT4+. In fact in many ways, the RD2000 is similar to the CAT4+, but has a number of stand out features which give the user more flexibility in using it. The main difference between the RD2000 and the CAT4+ is the ability to use more than one frequency – in other words they can be manually selected by the operator, unlike the CAT4+ which allows for no user input.

The RD2000 supports a number of different transmitters. Although they all look the same, the frequencies can be optimised for different types of industries.


We tested the TI-640 transmitter which allows direct connection using 640Hz, 8kHz and 33kHz, but depending on the transmitter being used, frequencies of up to 131kHz can be used, which are better suited to buried services such as twisted pair telecoms cable and insulated joints on pipes etc. Each of the transmitters has 3 different frequencies for direct connection (which is when you use the connection leads) and 2 different induction frequencies (which are used for the signal clamp or wireless methods of locating buried services). What is important though is to make sure that that transmitter is correctly paired to the receiver, as if the transmitter frequencies cannot be picked up by the receiver, you will be in for an impossible task of trying to locate anything. If buying a kit though, it’s far easier as all the pairing up is done for you. There are a number of locators (or receivers) available, and although they all look cosmetically the same, their frequencies are somewhat different. For example the + version is a multi-utility locator and the most popular, the TL is optimised for telecoms cable locating and the S version is aimed more towards using sondes to locate water and drain pipes.


With the CAT4+ it is only one transmitter, and one receiver with a single frequency (and an automatic small diameter locate frequency which is output at the same time). The RD2000 Super CAT range introduces a number of locators (receivers) and a number of signal generators (transmitters) which can be coupled to provide more flexibility for better locates. The lower frequency units can locate over long distances, and the higher frequencies tend to be better at locating small diameter phone and telecoms cables, as well as the small low voltage cables found in things such as irrigation systems and signal cabling.


We used the Super CAT+ kit and just like the CAT4+ it has everything you need to get going in a bag – transmitter, receiver, induction clamp, leads and connectors, earth stake, user manuals, calibration certificate, and a plug in connector, which allows the transmitter to be just plugged into a power point and a locate signal safely applied to the mains cables around the property. We thought this would be a really useful addition for building and pest personnel, but also useful in a wide range of other industries.

The RD2000 locator is not actually that different from the CAT4+ locator. The LCD screen is more or less the same deal here, with the mode function in the top right hand side and the bar graph taking up pole position on the screen. However the RD2000 has auto depth which means that it is no longer required to press a button for an impromptu depth measurement. As long as the RD2000 can display a depth reading – which must be in an active mode with the signal generator being used to introduce a trace frequency to the buried cable or pipe then the display will automatically display that depth.


The signal generator is a little smaller than the CAT4+ which we liked a lot. The CAT4+ genny has a useful toolbox built into the bottom, but the RD2000 transmitter is in our opinion a little sleeker and looks better, but this nothing more than a cosmetic detail. However the signal boost switch has been replaced with a frequency selection button. The signal boost button is not required on this transmitter, as it is a 1 watt version, so has the same output power as the CAT4+ transmitter when it is used with signal boost.

A lot of the functions are very similar, but the RD2000 is more like a beefed up version of the CAT4+ for those situations where the locate needs to be further optimised. This underground locator is not quite the precision of the RD7000+ and above, but offers a compromise and fills in a price gap between the CAT4+ and the RD7000+ as otherwise there would be a $2,500 jump in price from the CAT4+, but with the RD2000 Super CAT, it sits in the middle of the price gap and is around $1,000 more than the CAT4+ and about $1,500 less than the starter kit for the RD7000+ locator.


We found that the extra frequencies made locating different cables and also metal pipes much easier in difficult conditions, particularly in gravel or rocky soil. The higher frequencies definitely couple more easily to telecoms and data cables and the low frequencies do not seem to stray as much onto adjacent buried services, making pinpointing easier. The one thing we did notice though was that the low frequencies were not as easy to get onto a buried cable as the higher frequencies, but they travel over longer distances. However, we had to use direct connection to achieve really good results with low frequencies.


The eCert which we liked so much on the CAT4+ is not a feature on the RD2000 series, and in fact the RD2000 is the only locator in the Radiodetection range which does not have eCert. It just means that you have to send the locator in to the service centre for calibration. The saving grace with this though, is that Radiodetection have an excellent local service and support network, as they are a global organisation, so it just has to be a case of not having the RD2000 for a few days while it gets calibrated.



The RD7000+ heralds the start of the high performance, precision underground utilities and service locators, and belongs to a family of equipment which is based on a higher specification than the CAT4+ and the RD2000. The RD7000+ is a completely different underground locator, built around a much enhanced set of features and specifications aimed at precision location of cables, pipes and underground services and utilities.

We tested out the RD7000+ PL T10 kit which has the most powerful transmitter in the range at 10 watts output, and is optimised for the location of buried power cables, although it is still capable of detecting pipes and other services.


With the RD7000+ locators, Radiodetection are offering 4 different variations of locators (or receivers) and 3 different transmitters. The locators are available in SL version, which is a general purpose locator for construction and general types of underground locating, the DL version which has a number of sonde frequencies and CPS (cathodic protection system) mode and tends to favour the pipeline industry. Finally there are the PL and TL versions. The TL benefits from having very high frequencies of up to 200kHz and is therefore targeted towards contractors performing locates on buried telecoms and small diameter cables, such as twisted pair. Finally the PL, which is the most popular locator we have is optimised towards the power industry. It has advanced features, such as depth on power, a host of selectable frequencies and fault find, which can work with an A-Frame to find cable sheath faults to within a 10cms accuracy on buried cables. All of these locators can work across different industries, but they are just optimised towards a particular market segment with slightly different higher end features.


The first thing we noticed about the RD7000+ locator was it’s weight. We were expecting it to be far bulkier and heavier than the lightweight 1.9kg unit it is. With something this lightweight and easy to handle it would be easy to do long site surveys without having sore arms or hands afterwards. We found it a really nice ergonomic locator to use, and felt that Radiodetection must have gone to a fair bit of detail in the design of the RD7000+.

The locator (receiver) in itself is a nicely designed instrument with a large clear screen, which is far larger than the displays found on the CAT4+ and the RD2000 Super CAT underground locators. It is a well thought out element of the RD7000+ with logical and easy to follow information, all designed to make the operator have an easy time of interpreting the data. As well as the frequency and signal strength, there is a compass which is useful in determining the direction of the cable, pipe or service underground and this is one of the features that sets the RD7000+ apart from the lower end detectors. It is built for precision locates and using it makes it feel like the precision instrument it is.

We had the PL version of the RD7000+ which Radiodetection say is optimised for the power industry, with a bias on location of buried cables. However the PL+ will still work with a Sonde and reel or push rod to locate plastic pipes, but it doesn’t have the array of sonde frequencies found on the DL version. The PL+ has one single 33kHz frequency, but make up for that in other areas. One of the most useful features we found was something called depth on power. Lower end underground locators when used in power mode (to locate a live cable without the use of the transmitter or signal generator) cannot display any depth reading – to do this it must be used with the transmitter connected. The RD7000 PL+ can display the depth of the buried service, even in power mode without the need to connect or use the transmitter. It works well with Strike Alert so that as well as having the reassurance of an alarm if you get close to a live cable, you can also read the depth, even if you are not that close, which allows for even safer digging, as knowing the depth of something gives you that extra dimension.

There are a number of transmitter options available which include a 1 watt version (the TX-1) a 5 watt version (the TX-5) and a 10 watt version (the TX-10). To put this in perspective, the 10 watt version offers 100 times the output power of the CAT4+ Genny in standard mode and 10 times the power, even when the CAT4+ transmitter is used in signal boost mode. The LCD display on the RD7000+ transmitters is a very welcome addition, with the ability to look at the settings in an instant and to change any of the parameters in no time at all. With the 90V output option, we were able to apply a signal to a buried mains cable in our building and trace it back almost to the distribution board, which is located several hundred meters away. Radiodetection have included this higher voltage option for high impedance applications, which also works surprisingly well on poor soil conditions with temperamental signal return paths. We managed to get excellent depth accuracy across the whole of the line we were tracing, with the vast majority of it buried underneath a car park.

Looking at the range of transmitters, they look ergonomically good and are functional. Like the CAT4+ you get a nice tool tray built into the bottom of the transmitter to store the leads and earth stake, but these transmitters are both powerful and fully featured, for precision underground locating. Radiodetection have added a range of features, such as Side Step Auto, which automatically selects a frequency based on the ground impedance, and a built in multimeter function, which can measure power, voltage, line current and give the user all sorts of useful information relating to the characteristics of the profile of the locate.

By adding the A-Frame accessory, which costs around $1,000 extra to the set up, it allows for more advanced operations, in particular fault finding on underground power cables. We didn’t try out the A-Frame, but Radiodetection say that it is capable of locating cable sheath faults to around a 10cm accuracy on buried services, which allows for not only locating cables, but finding faults as well. Considering that a TDR costs around the same as the A-Frame accessory, it represents decent value for money.


The accessories that work with the RD7000+ are all plug and play, so don’t require any setting up. Simply plug in and they will work, with the minimum fuss and effort.


With the RD7000+ kit which we had, everything is supplied in a purpose made carry bag with multiple pockets to store everything. The kit consists of the transmitter, with leads and earth stake, the receiver (locator), an induction clamp, calibration certificate and manuals.


There are such a lot of features built into the RD7000+ system, that it’s actually quite difficult to list them all out precisely, but what is fair to say is that we liked a number of things about it. The dynamic overload protection works really well in electrically noisy or congested environments to filter out those annoying influences that can come from elsewhere, other than the target cable or pipe, such as overhead cables, high voltage equipment and so on. Like the CAT4+, the RD7000+ also has eCert to allow for remote calibration, which can be done without the locator being send back for service. The user just connects a USB cable, and follows the on screen instructions to verify the calibration values and save or print out a calibration certificate.


There are a number of frequencies available, and various modes for precision locating of services, some active and some passive, plus induction modes allowing for tracing of buried services with the supplied induction clamp, or even wirelessly where the transmitter is just put on the ground above the buried service and wirelessly couples a signal for locating the depth and direction of the cable or pipe. The compass built into the display, we thought was a very useful touch for confirming the direction of the buried cable, which in turn allows more accurate depth readings, and even aids with comparing the readings of the RD7000+ to any drawings or plans.


What we liked Most:

Superbly well featured cable locator, quite easy to use, lightweight, remote calibration function, wide choice of locators and receivers, backwards compatibility, built in compass, depth on power, plug and play


What we didn’t like:

Being around $5,500 to $7,000 worse off for owning one (if that is really a negative, compared to the cost and risk of cutting through a mains cable).



The brand new RD8100 underground locator range takes the specification of the RD7000+ and goes even further. In our opinion, this must surely be one of the most advanced cable avoidance systems available anywhere in the world. It is bristling with all sorts of features which make locating underground services and utilities as precise as possible. Radiodetection say that the RD8000 locators have been further improved by adding a further antenna, which improves the locator performance in null mode and makes locating slightly more accurate still. With the extra antenna, the RD8100 now has a total of 5 antennas, which is a unique arrangement for Radiodetection.


One of the other features which we use on the RD8100 was in the integrated GPS and data logging which allow certain usage statistics to be saved. We thought this feature would be useful for training and / or quality management systems as it allows information relating to how the locator was being used to be stored for later analysis.

The RD8100 offers all the features as the RD7000+ and adds the multitude of extra advanced options designed for even more precise and easier underground locates. For example, the iLOC feature is something we found extremely useful to stop having to walk back to the transmitter each time a setting needs to be changed. With this feature the Bluetooth connection between the transmitter and the receiver enables the operator to make adjustments to the signal generator. This can be done from distances of up to 450 metres outdoors. As well as this records saved in the RD800 memory can be wirelessly transferred to a Bluetooth enabled PC or mobile device.



The GPS function we thought was really handy as the locator captures positioning every second and when used with Google maps to confirm where and when different locators were performed.


The other thing which stood for us about the RD8100 was the huge amount of frequencies available. We used the PDLG version which has 18 different locate frequencies and 4 sonde frequencies as well as 5 different passive modes, GPS, usage logging, depth on power, and iLOC. We coupled this with the TX-10B transmitter which has 10 watt output power and a whopping 36 active frequencies and 8 different induction frequencies. As if this wasn’t enough, we also have 14 different current direction frequencies. Current direction allows a specialised signal to be output which is extremely useful to pinpoint a target line which might be located amongst other parallel utilities. When using this mode it was a case of following the guidance arrow on the locator screen to stay on target. The TX10-B also had the 4 kHz frequency which is specifically designed to locate higher impedance utilities over longer distances. This works particularly well on congested areas, such as Telstra cables and street lights. The RD8100 is also equipped with power filters which help tracing power cables in live mode (without the transmitter) this works to filter out harmonic power signals to pinpoint whether a signal is being emitted from a single source or from parallel cables which can be individually traced.


Like the RD7000+, the RD8100 is equipped with the same array of features, such as TruDepth (which means depth readings are only given when the locator is oriented), eCert allowing for remote calibration with no down time. Peak and null mode, fault find - which allows the use of an A-Frame accessory to pinpoint underground cable insulation faults to within 10cms, Dynamic Overload Protection (to reduce external interference). The RD8100 also is supplied with RD Manager software which allows for setting up of the locator and downloading of stored data to a PC.


We liked the fact that not only is the RD8100 a very powerful service locator, but also very customisable to make it suitable for precision use in various industries. There are a number of locator options, and a choice of transmitters in different power outputs, with or without iLOC. We thought that the iLOC was well worth the extra $400 or so for the convenience of not having to keep walking backwards and forwards to the transmitter. We thought that it would be a real hindrance to have to try and mark a position, walk back to the transmitter to change a setting and then walk back to the original position and start again. It is much easier to control both transmitter and receiver from one place and saves a load of time, especially when the frequency has to be changed a number of times.


All in all, the RD8100 is not dis-similar to the RD7000+ in terms of size and weight, but adds some really nice features which will set you apart from your competitors if you really want to go out there and impress your customers. It really is a fabulous piece of kit.


What we liked Most:

Loads of features, unparalleled accuracy when used properly, compatible with RD7000+ accessories, fully customisable, iLOC Bluetooth connectivity saves loads of time, very precise in various modes, lightweight and ergonomic, heaps of frequencies, GPS works with Google maps, remote calibration can be done by the user easily, Radiodetection seem to have thought of everything.


What we didn’t like:

Can be slightly expensive at over $8,000 starting price for a full kit, so many features that take a little while to master them all, but once done it’s a brilliant piece of equipment.


Value for Money:

If all you need is a basic underground cable locator with no advanced features and have a limited budget, then the CAT4+ would be the locator kit of choice. For the $3,000 mark, you get a full kit which can be used to identify the presence of a buried cable or pipe. You don’t necessarily get precision features, but the CAT4+ is still a very capable locator system. However if you need to consider multiple frequencies, for instance to get the best out of trying to find Telstra and other communication cables, then perhaps the RD2000 would be a better choice, as it has up to 3 frequencies, but it is also available in a choice of standard frequencies, but the TL kit is better for telecoms cables as it can be purchased in a configuration with up to 131 kHz for small diameter cables, such as those twisted pairs. While the RD2000 is slightly more expensive than the CAT4+ it is still cheap enough at around $3,500 to $4,000 to compete with the CAT4+ on price.


The RD7000+ and RD8100 are, simply put in a different class to the lower end locators, and starting at over $5,000 for the cheapest RD7000+ kit up to nearly $10,000 for the top end of the RD8100 (with just about everything else in between) there is plenty of choice. In our opinion, the RD7000+ kit with the 5 watt or 10 watt transmitter offers a sensible compromise between precision and price at around $6,000 to $7,000 depending on the configuration. If money plays a second place to precision and you want the best Radiodetection kit, then the bottom line is that the RD8100 with the TX-10B is difficult to beat.


Each of these underground service locators has a place in today’s marketplace. Depending on which industry you are in, then different features are of different importance, but the main thing is that Radiodetection make a service locator which fits in just about anywhere in the field of utilities location.