The LR50W is the crossover receiver - the one tool that covers both a dozer and an excavator, with the RD20 wireless display in the cab. It gives a 6-channel display in excavating mode and a 5-channel display for centre on-grade, on a 6.75-inch photocell.

On an excavator the reading is only true when the dipper stick is plumb. The LR50W tells you where you are: with the stick extended the LEDs blink fast, in the plumb position they are constantly lit, and with the stick retracted they blink slowly. The operator finds plumb without guessing, which is what makes the depth reading trustworthy.

Yes. A button combination toggles the receiver between wireless mode and hard-wired RS-485. If you switch it back to wireless afterwards, the receiver and the RD20 have to be paired again - the procedure takes about ten seconds and we can walk you through it.

It mounts on the machine - on a mast, a blade or a dipper arm - and reads the plane from a rotating laser you have already set up. The receiver tells the operator whether the cutting edge is above grade, below grade or on grade, so nobody has to stand in the trench with a grade rod and the operator does not have to stop and check.

Deadband is the size of the on-grade zone. A wider band is quieter and steadier, which suits a first pass or rough grading; a narrower band is tighter and suits a finish pass. Measured from the centre on-grade position the settings are 5 mm (0.20 in) fine, 10 mm (0.40 in) standard and 20 mm (0.80 in) wide. Working from an offset on-grade position they are 12 mm (0.50 in), 25 mm (1.0 in) and 50 mm (2.0 in).

Offset moves the on-grade zone away from the centre of the receiver to wherever the laser is striking it. That means you do not have to physically move the receiver when the grade changes, and if most of your work sits above or below the reference you can shift the zone so the laser is in the window more of the time. On an excavator, setting on-grade high gives the operator earlier warning that the bucket is approaching depth.

The receiver will read a laser from 105 to 1200 RPM, but that is what it tolerates, not what works well. In practice you want 600 RPM as a minimum, and faster is better. The reason is strikes: the faster the laser spins, the more times the beam crosses the receiver every minute, and the more often the display updates. At a slow rotation the reading lags behind what the machine is actually doing. That matters most on a skid steer or a dozer, where the operator is making quick changes in elevation or travelling at speed - a slow laser leaves the display chasing the blade. On an excavator working one spot at a time it matters less. If your laser has a variable speed setting, turn it up.

Yes. These receivers are rated IP67 - sealed against dust and against temporary immersion in water - which is what keeps repair costs down on a machine that works in mud and gets washed.

Built-in clamps fasten the receiver to a square or oval mast and hold it even if the machine is slammed or shaken. Three mounts cover the rest: the CTO-MMM mini mount for backhoes, skid steers and mini excavators, the DM-20 bolt-on dozer mount, and the MM-1 magnetic mount for dozers and excavators. Call us and we will tell you which one suits your machine.

Yes, and it is one of the reasons contractors buy these rather than a full control system. The receiver comes off one machine and onto the next with the right mount. One receiver can cover a small fleet instead of sitting idle on one machine.

Yes. This is a wireless-capable W model, so it pairs with the RD20 remote display and puts grade in front of the operator in the cab rather than out on the mast. The link is Zigbee, not WiFi. The RD20 and receiver are paired at the factory, and they can be re-paired in the field if you move one between machines.

Yes, and it is the part people are most surprised by. The RD20 gives audible tones, the same way a receiver on a grade rod does - one tone for high, one for on grade, one for low - so the operator does not have to look at anything. Eyes stay on the boom, the bucket and where the machine is going, while the ears follow grade. It runs at 105 dB on the loudest setting, which carries over a running machine, with 95 dB and 65 dB options and an off switch if the cab is quiet. For a lot of operators this is the single biggest reason to put the display in the cab rather than squinting at a receiver out on the mast.

Deadband, on-grade offset, excavating mode, receiver LED brightness and - on the LR60 - tilt match, all without leaving the seat. It shows red, green and blue elevation LEDs plus an audible tone at 105 dB, 95 dB, 65 dB or off. It runs from machine power at 10 to 30 V DC using the supplied 010983 cable, or from two AA batteries for about 20 hours on alkalines. It mounts with a quick-disconnect plate, adhesive tape or magnets, and there is an optional swivel suction-cup mount for the cab window.

Spectra's user guide lists the built-in stainless steel clamps as fitting round tube 42–50 mm (1.66–2.00 in) or square tube 38 mm (1.5 in). Do not clamp to a painted pole: paint can build up on the clamps and wear them out.

Per Spectra’s user guide the charger is for the rechargeable NiMH batteries only; do not charge alkaline or other disposable batteries. The receiver will not operate while it is charging, so plan to charge it between shifts. A charge-status LED on the back of the housing shows progress.

Yes. Per Spectra’s user guide the receiver turns itself off after 75 minutes with no laser beam, which helps save the batteries.

Genuine Spectra parts for the receiver: Spectra 010536-99 (carrying case), Spectra 010542-99 (charger adapter), Spectra 010897-99S (replacement mounting knobs), Spectra 010459-99S (replacement clamps), Spectra 002102-99S (battery door thumb screws).

Contractors-Tools.com, an authorized Spectra Precision dealer. We set these receivers up every week. Tell us the machine and the laser you are running and we will spec it before you order. Call 1-877-866-5721.