All Materials Locator, orArm Movement Locator?

Sold as a revelation

1Fourteen years on sale. Still called “All-New”. Still used by nobody.

Anyone who has been in this industry a while has known about this device since 2012. It was FCC certified that March and written up in the trade press that August, and the data sheet still calls it “All-New” today. If you are meeting it for the first time it will be presented to you as a breakthrough, which after fourteen years it plainly is not.

In fourteen years it has not appeared on the published method statement of a single mainstream UK utility mapping contractor reviewed for this work. It is not named in PAS 128, not in HSG47, not in NJUG guidance, not in the Survey Association’s published methods, and not in ASCE 38.

A handheld that genuinely found PVC pipe at twenty feet with no transmitter on it would have been standard kit at every survey company in the country inside five years. The money was there over that period and it moved. It moved towards instruments that measure.

Their own word for it

2They call it powerful. Their laboratory measured 41 milliwatts.

Before any of the physics, there is a word in their own sales literature worth sitting with for a moment. This is the manufacturer’s current brochure, live on their website today, and the UK seller reproduces it line for line in the guide it hands to customers here.

“Using advanced circuit board technology, powerful 2.45 GHz ground penetrating, UHF radio waves locate PVC pipes easily.”

SubSurface Instruments, AML Pro brochure, current

Powerful. Ground penetrating. Their words, not mine. So let us take them at their word and ask the obvious question. How powerful?

There is a published answer, and it is in their own certification file. When the unit went to the laboratory in 2011, its strongest emission measured 111.4 dBµV/m at three metres. That is a field strength reading, which is how this class of kit gets measured instead of in watts.

Two figures get quoted for this device because they measure different things, so here are both. Averaged out, the American rule it is certified under allows 0.75 milliwatts, which is the number in the box at the top of this page. On brief peaks that same rule allows about 75, and their own laboratory recorded 41. I will use 41, because it is the most generous to them.

On its own that number means very little, so here is what it sits beside. The device holds one FCC authorisation, granted in 2012, under a rule called section 15.249. That is not a rule for survey instruments. It is the low power gadget rule for the 2.4 GHz band.

Pull a cordless mouse off the FCC database and its test report is filed under that same section. So is a wireless keyboard. Same rule, same band, same ceiling. A cordless keyboard has to push a keystroke about a metre across a desk, and it is allowed getting on for twice what this device was measured at.

So powerful, here, means a shade under what the keyboard on your desk is permitted.

Now set that against what the same literature asks you to accept. The manual says the signal penetrates up to twenty feet on average, with the depth depending on the substrate. The brochure says, separately, that the device works in clay, wet soil, snow or even standing water.

And on the opening page of that same brochure, a few pages before the powerful ground penetrating waves:

“Unlike the deficiencies of GPR (Ground Penetrating Radar), the AML will work in clay, wet soil, snow or even standing water.”

The same brochure, opening page

So it is not ground penetrating radar, and its radio waves are ground penetrating. One document, both claims, a few pages apart. I would genuinely like somebody to tell me which of the two they meant.

Who is selling it to you

3Distributors of safety critical kit have a duty

I published this ten weeks ago. In that time I have been called jealous. Obsessed. A misogynist. A man with too much time on his hands and too many people listening to every word of his genius. All of it in public, all of it from the business development manager of the company that sells this device in the UK.

Not once, in ten weeks, has anybody come back with a factual rebuttal. Not one line about the physics. Not one number. Nothing about the patent, nothing about the FCC record, nothing about what the inventor himself told me.

I have never named the distributor and I have never named an individual. I am not starting now.

But here is what I keep coming back to

This is safety critical kit. It goes into somebody’s hands on site and it is supposed to stop them putting a spade through a live cable. Anyone selling that has a duty to understand what they are selling.

Their own business development manager, publicly, back in June:

“[the distributor] just work’s with and supplies what works for the end user, it’s not our job to understand the technology a 100%, it either works or it doesn’t, most clients say it works for what they need it to do, to avoid damaging buried utilities or locate the stuff they just can’t find!”

A UK distributor's business development manager, publicly, June 2026

Read that twice. He knows exactly what it is for. Avoiding damage to buried utilities. And in the same breath, understanding how it does that is not his job.

Pushed on it in the same thread, he went further:

“if you need to understand it, to make use of it, don’t buy it, I don’t understand how my electric car works, but it works, most of the time, does that job?”

The same, in reply to a competing manufacturer's sales manager

The science does not work

4The signal is gone before it gets anywhere near your pipe

It runs at 2.45 GHz. That is not a slur, it is on the FCC certificate. And it is the exact frequency a microwave oven uses.

Ovens run at that frequency for one reason, which is that water absorbs it. That is why your dinner comes out hot and the plate it is sitting on does not.

Now point the same signal at the ground. Wet clay is mostly water as far as a radio wave is concerned, and it does to that signal exactly what your dinner does to it.

The measured figures are these. In pure water the signal is spent inside 1.4 cm, and in wet clay it manages about 3 cm, which is roughly the width of two fingers. The brochure promises 610 cm, and it has to make the trip back up again afterwards.

What it actually detects

5The only thing it detects is your hand moving

Inside it there are five aerials in a row, one that sends and four that listen. None of this is guesswork on my part, it is all set out in the inventors’ own patent.

The one measurement it takes is this. A radio wave is a ripple, and the two listening aerials sit at slightly different points on it. The device measures how far apart those two points are, a chip compares them and puts out a voltage, and when that voltage sits at about 0.2 volts the light comes on. Drift off it and the light goes out. There is nothing else to the decision.

What it never measures is how long the wave took to go down and come back again. That timing is the only thing that gives you a depth and it is what real radar is built on, and there is no timer in this device at all.

One ripple at this frequency is about 4.8 inches long, so half a ripple is 2.4 inches. Move the device that far, or simply tilt it as you walk, and two aerials that were in step with each other are now opposite, and the reading flips over. The inventors put it in the patent themselves:

“the measured phase difference can vary rapidly with slight movements of the apparatus”

US 7,898,456, Cloutier and Oehme

And the manufacturer tells its own customers the same thing, from the other end:

“Both lights will come on then go off approximately every 2 inches… A gentle flicker up and down or a vertical motion will allow the pipe to be accurately re-located.”

SSI AML FAQ

And before anyone tells me they would settle for half a metre. Nobody needs to argue about twenty feet, so take the depth that actually matters on a job, a service at around half a metre down. In wet clay that round trip costs somewhere between 145 and 290 decibels, and UK law allows this device about 134. Half a metre has already gone, and a metre has gone by a mile.

One more from their FAQ. Asked why it gives readings where the user knows there is nothing buried, the fix they offer is to turn the sensitivity down.

Selling point one

6There are no NASA engineers. I found the man who built it instead.

The manual and the brochure say the technology was “originally designed by NASA engineers for use in lunar exploration”.

Every subsurface sounder NASA or ESA has ever flown to the Moon or Mars operates between 1.3 MHz and 158 MHz. Apollo 17, MARSIS, SHARAD, Kaguya. Not one has flown at 2.45 GHz, for exactly the reason above. Apollo’s lunar sounder was a 43 kg instrument with a sixty metre antenna and a spacecraft’s power budget, working through dry lunar dust at 5 MHz. This is a 2.5 lb handheld proposing to beat it in wet British clay.

So I went looking for these NASA engineers, and there are none. The patent names two real people instead, and I wrote to the one still with us, Professor Paul Cloutier, a physicist at Rice University, fully expecting to hear nothing back. He replied within the hour, and twice more the day after that.

It was never a space programme. It began as a landmine detector for the US Defense Department. An early version was trialled by the Army at Fort Belvoir against mines at two to twelve inches, in prepared lanes of known soil. That is about the easiest task you could set it. It was disqualified anyway, because it indicated on empty ground more than one time in five. A device that lights up over a fifth of empty ground is not detecting anything, it is simply indicating nearly everywhere it goes.

They went on to test it against PVC water pipe buried at one to two feet, which is a long way short of twenty, and then they stopped altogether. I asked him why.

“the fact that we did not pursue it any further is a summary statement of our understanding of its utility and value at the time.”

Professor Paul Cloutier, co-inventor, in correspondence for this report

He read the report before publication and allowed me to quote him.

What to use instead

✓The methods that work all tell you how they work

Active EM puts a signal onto the pipe or cable itself and reads the field it re-radiates. It works on conductors, and it says so.

A sonde is a transmitter physically pushed inside the pipe. It works in any material, because the source is inside.

GPR at 200 to 1,500 MHz measures travel time and records a radargram you can re-read. Every manufacturer publishes the frequency, the depth assumption and the soil conditions where it struggles.

None of them claims to work in clay, wet soil, snow and standing water without qualification, because no such claim survives contact with the physics. If someone has sold you an AML Pro, do not put it in front of an excavator as your locating method of record, and treat any indication it gives as unverified until a second method confirms it.