PimentoUK

Please.

Deus .... D.E.U.S pronounced day-uss. Not Dues rhymes with snooze or juice.

Interestingly, a 20" Eqx coil was going to be my first coil project for it. I got the donor coil for the pre-amp electronics PCB ages ago, it's just that I have no time to make the thing, life's too complicated ( for me ).
I felt the 20" would be good for non-motion deep target hunting, as well as being still useable in a conventional way.

"Right below it .. but I'm thinking it might be made of aluminum alloy. It is brittle, bent, and broken but quite decorative"

I think it's silver, possibly a decorative band around a walking cane, probably 1800's vintage. Try the "spit & foil" test on it to see.

( For those who don't know: Spit on the silver item, apply a piece of aluminum/aluminium foil, and use a tiny bit of light rubbing to get the two metals in contact. You should get some fizzing/bubbling, and a foul 'rotten egg' sulphur/sulfur smell. The silver will shine-up, as the black salts are removed. This technique can also be used to clean up the item, as it will selectively clean the high-points, leaving the dark patina in the recesses. )

English language press coverage:

https://www.express.co.uk/news/science/1532563/archaeology-news-rare-gold-treasure-found-earrings-vikings-denmark-middle-east

https://sputniknews.com/20211206/world-class-1000-year-old-egyptian-earring-found-in-danish-field-perplexes-researchers-1091276469.html

 

"I'm properly confused"
You will be if you look at an article describing how to noise-cancel a completely different detector ... and a PI one, especially.

It's safe to assume that it's going to examine a more 'raw' version of the signal coming from the coil, and any sensitivity, discrimination, notching, volume, or hyperchromatic birefringency settings you have in place will be ignored.

Please show us some old coins and ancient Thai relics.

Agreed, something similar to an Ebex 420.

"Just curious how notching on F75 would work ...?"

Not wanting to take this off-topic, but:
Disc and notching do apply to ONE of audio or visual display, I honestly can't remember which.. 'display' is the likely one. I recall NASA-Tom Dankowski coming up with some 'optimum' disc setting that he found eliminated small iron ( nails ) but let the maximum amount of other stuff through, and it always seemed to me that it was playing on this audio/visual difference. A disc setting of '6' seemed to give audio more like '12' .. ?
Anyhow, it was never something that troubled me. I found the machine worked best if you ran it fully open with no disc settings, ( ie. tone ID; all metals accepted). The moment you start introducing any kind of discrimination, you start getting into the wierd zone. The machine has many quirks and design flaws, the User Manual is no help, using 'Notch' is asking for trouble, it has notch-related functions the manual doesn't even mention, it's easy to invoke some notch setting and not realise it, and because you can't set discrimination higher than 65 ( why? ) , you can't properly make use of the 'notching in' feature....

And then there's the odd relationship between disc setting and sensitivity, unexplained, that makes the glaring 'sensitivity hole'.

And the ridiculous step change in EMI pickup when you change 'disc' from 5 to 4.

 

NASA-Tom's mega-thread on the F75:

http://www.dankowskidetectors.com/discussions/read.php?2,4402

Enjoy.

Very pure water has a noticeable blue tinge to it. For example the stuff the semiconductor industry use to wash silicon wafers with during IC manufacture. It's not caused by scattering, like the blueness of the sky/sea, it's due to a particular molecular absorption in the middle of the red part of the spectrum, that then leaves the remaining light transmission blue-green tinged.

But apparently, if the hydrogen is replaced by deuterium ( hydrogen with an extra neutron in its nucleus ) it makes clear water. The H atom is heavier, so the O-H bond vibrates at a lower frequency, shifting the red absorption out to the near-infrared. So the visible light passes through the heavy water unimpeded.
I've seen wafer-fab water, and it really is blue. Heavy water is a bit niche, especially super-pure stuff, so I can't verify what that looks, tastes or smells like.

( speaking of taste: one clever bit of science involving heavy water, is the "Doubly-labelled water" experiment, which allows you to evaluate how much energy your body is consuming, by monitoring the water inside you. It needs special water, with deuterium and heavy oxygen to isotopically label it. The CO2 you breathe out means you lose oxygen at a different rate to hydrogen. The harder you work, the more you breathe. By tracking the decay of H and O, it's possible to quite accurately determine energy expenditure. )

When I was at school/college, this theory was used to suggest that ALL metals should be 'yellowish' , and the mystery was: why is nearly every metal in practice silver-coloured? Everything from light Lithium to heavy Lead seems uniformly silver/grey.

Gold is definitely shinier out into the infra-red range, hence why spacecraft tend to be smothered in gold foil. And in the engine-bay of the rather exotic McLaren F1 road car.

"Is pure nickel sometimes used in inexpensive jewelry? "

I think it's more likely to be nickel-plated, probably with a decent thickness, and the underlying metal is brass or bronze. If the plating is substantial enough, a magnet will be attracted to it.

"Segments and tones just lump the ID ranges together? "

Broadly speaking, yes, that's what happens.
However .... the audio and the visual ID's do not HAVE to correlate. Audio performance needs to be fairly 'immediate' , whereas a visual identifier can be slower. Advantage can be taken of this difference to produce visual data that is more 'averaged', to produce more repeatable/consistent/less jumpy information.

I've no idea what ML do on their Eqx/Vanquish models, but as an example from First Texas Products:
The Teknetics T2 machine used exactly the same processing for audio ID and visual ID. It's design was later developed into the improved 'park-hunting variant', the Fisher F75. This used different processing for the two outputs, and their publicity material drew attention to this improved target ID ability. As a user of the F75, I have seen the odd 'discrepancy' that this produces. We have a lot of coke ( part-burnt coal ) in our UK farmland, and it often reads in the very-low non-ferrous range, but can be in the 'large iron' zone, or up as high as some coins. Sometimes a lump will consistently give 'Iron' audio, but low non-ferrous ID's on the screen.

The 4 inch BH coil is cheap, that's one good thing. It will fit a fair range of machines, including the Fisher F2/F4. These have all the electronics self-contained, so they can easily be refitted onto a custom shaft. I have this coil, and it does seem to pick up electrical interference, though. Maybe the screening/shielding is a bit minimal, being a low-end BH product.

Your 'conductivity table' does have a rather glaring error : you have included ferromagnetic materials among the 'non-ferrous'; namely iron, steel, nickel. These will all read as "Iron" to a detector, as their phase shift will be 'negative' , relative to the non-ferrous scale.
Hence why the nickel-plated steel Thai coin reads with a -ve number. The detector sees it as an iron-plated iron item.

It's worth accumulating a random selection of foreign coins, for 'scientific testing' purposes. Ask around your friends , see if they will donate / sell you their leftover holiday change for face value. USA money is often used as a reference, that's one coinage worth looking for.

For interest, pure nickel is unlikely to be found in the ground, though Canada did make their 5 cent coin from it for many years.

You need to tell us what country you live in, if you're wanting a suggested supplier.
The connector is a type known as "M12" , and it's an 8-pin free socket.
If eBay is any good in your country, it may be worth looking on there.

As an example from a UK industrial supplier, Farnell, there is this 'field-installable' type, with screw-in wire terminals, so no soldering needed:

https://uk.farnell.com/te-connectivity/t4110012081-000/sensor-connector-m12-rcpt-8pos/dp/2627715

If you register on Geotech1 forum, there's a thread about the Eqx coil:
https://www.geotech1.com/forums/showthread.php?25445-ML-EQUINOX-coil-discussion-thread

 

A few notes regarding the metal conductivities:
The 60% IACS figure for Al is for pure, or near-pure aluminium. Everyday kitchen foil is near-pure, as are the thicker foil types that are used for food containers, pie trays etc. They have the distinguishing characterisitc of being very soft. All aluminium alloys that are created for strength, such as beer/drinks cans, and their ring-pulls/tabs, have noticeably lower conductivity, a typical figure is 37% IACS.
Likewise, pure gold is rarely found used in jewellery, it's too soft. Alloying it with copper/silver and sometimes nickel to change the hardness/colour/carat significantly lowers the conductivity. Figures in the 5 - 20% IACS range are typical. For example, 0.900 fine gold, as used in older USA coins, has conductivity of 15% IACS.
Cupro-nickel is widely used for coins, and 5% IACS is a typical figure. Your 1986 1 Baht coin will likely read low down, about 10 on the Vanquish ID scale.
Here's a decent table of conductivity for many metals/alloys:
http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/

 

You will soon have plenty more older coins, it's not usually hard to find coins over 100 years old. You have a good machine, it will soon reward you with some great finds. Don't forget to show us, especially the silver ones.

"Is it the strength of the amplitude of the return signal?"

Yes, it's based on the change in signal strength as the target is swept over. It's not the total signal strength, as that will obviously include the continuous signal from the ground ( and the continuous coil signal that every coil creates due to imperfect nulling of the wires ).

The signal strength varies quite dramatically with the depth of the target. If you're mathematically skilled, a fair practical approximation is that signal strength varies with the inverse 5.5th power of the distance from the coil. This means, for example, that increasing target depth by just 15% (eg. 7" to 8" ) causes the target signal to fall 50%.

I assume you're actually referring to the 'on-the-fly' depth gauge than many machines have, the 'Shallow/Medium/Deep' bar-graph? They will just use a simple number comparator system. If signal-strength is more than xx, show the shallow bar, etc.
If you were talking about the depth indicator in pinpoint mode, it may be the same system, but extended to 16 levels etc, so a signal that's more than '100' and less than '135' would result in '7' being displayed to indicate 7 inches.

Obviously all these scales/bargraphs need some kind of 'calibration standard' target for accuracy ..... and there isn't one. Surprise surprise. It's generally considered that a 'medium-sized' coin is appropriate, something like a USA 5 cent  seems a fair example.
My Fisher F75 has a surprisingly accurate pinpoint-mode depth gauge. I've investigated its calibration, with coins like US 5c and 1c , and it gives very straight-line graphs for 'indicated' vs 'actual' depth. The F75 does most of its signal processing inside a DSP microcontroller, so can presumably perform quite precise and repeatable assessment of strength. Plus, you would typically move the coil slowly in pinpoint-mode, so it may do more signal averaging, to cut down noise and create a more stable reading.

Back on-topic, I see the coil has just two small flat gold-plated pads for the battery charging, like on the previous model. It would be better to have two pads per terminal, to reduce the chance of a poor connection, and to give longer service life, as the plating will wear over time.

(this is standard on many switches and relay contacts, where one of the contacts has multiple fingers. As well as making a better connection, it affects issues like arcing and contact-bounce. It's also used on some motor commutator brushes, where bounce inevitable happens, and the inductive nature of a coil-of-wire gaurantees back-EMF voltage spikes.)

Alternatively, use larger pads, so the clip-on charging device can use two or more probes per pad.

"I don't know in the UK"
The Eqx has proved to be very successful and popular inland, in the UK. The Park1/Field1 modes are pretty decent all-round hunting modes, and Park2/Field2 are effectively 18kHz modes with extra depth due to Multi-freq, so they hit the spot that the XP GMP and Deus on 18kHz do so well, but the Eqx does it better ( especially considering the large coil size ).And the beach guys like it, as it's more ergonomic and lighter than the E-trac/Safari/other BBS they tended to choose, and waterproof too.

It's true that the performance is what matters, and the Deus2 could use innovative tech, but not necessarily deliver gains in 'finding stuff'  -- for example clever design may be responsible for the coil having 10 hours run-time, say, whereas if they had used 'regular' designs, the same battery may only have given 4 hours run-time. So the user is seeing a benefit ... but not in finds haul.
However your "stability in black sand" criterion is only one way of assessing how good /bad it is. Here in the UK, beach detecting is not the most popular niche, and farmland, ploughed or pasture/grazing , are the preferred locations. Our soil is busy with junk, but isn't actually strongly mineralised, in general. So most of the UK's prospective Deus2 customers are looking for gains that may be delivered by a machine that's nothing special in a 'black sand environment' .

Quote: "Putting an FFT Scope on the detector to count generated waveforms to settle the "number of frequencies" debates is really meaningless and a waste of time, also."

I don't agree, I think it's interesting to see what's really being done.

For one thing, it dispels all the marketing baloney claims, so people can disregard it. Remember when Minelab added the 4kHz option to the Eqx, and folks were wanting to know if it had been added to the 5/10/15/20 etc mix of the Multi-IQ mode, too? If they were properly informed, they would know there are no 5 or 10 or 15 etc in Multi mode anyway, so expecting 4k to be added would be a bit optimistic/unrealistic.

And secondly, a 'scope will show if XP have created something truly different and original, that no other machine has. For example, they may be using 'direct digital synthesis' (DDS), to drive the coil with near-sinusoidal waveforms, so it actually looks like 3 sine waves on the coil, not a mess of square-edged signals.

It's just possible they are actually transmitting a single square signal, and doing clever RX signal processing, much like the Tarsacci does.

Or... consider those expired Minelab patents for BBS, with sequentially-switched dual frequencies ? There's plenty of scope to do things with that tech. ML only used 3.125kHz and 25kHz for all their FBS/BBS machines. But the 1:8 ratio isn't actually important, and the individual freqs can be tailored to suit the targets you're hunting. So "4k & 32k" for silver coins, "7k & 28k" for general hunting, "15k & 45k" for small target hunting.

It could be fractured wires inside the cable, close to the point where the cable enters the back of the connector. There is often a lot of flexing in that area,  close to the strain-relief clamp, and wires will eventually fail.

The 'technical stuff' about frequencies really needs ignoring for now. Only when someone gets an oscilloscope, spectrum analyser etc near one can you really say what may be going on.
I'm skeptical about the sheer number of frequencies. My hunch is they may use three at a time, and choose which three depending on the mode selected, so they would use a lower-weighted selection for the 'milled silver coins in parks' mode, a high-weighted blend for 'sensitive' / ancient targets in old European farmland.
This is something I'm surprised that Minelab haven't ( yet ) done with the Eqx platform. ( or the FBS/BBS, in fact ). Currently, all the basic modes on the Eqx use 7.8kHz / 18.2kHz / 39kHz, but in principle they could shift them all down, to create, for example 6k / 14k / 30k : same ratios, same maths, just biased towards 'milled silver coin' hunting.
So, for this Deus2, the combination of (4 + 28 + something inbetween) may be the high-conductor blend, and ( 7 + 45 + something inbetween) may suit the medium/small target applications. "Pick a frequency, any frequency".

"Shouldn’t target conductivity be included?"

I agree, it's a bit vague, especially coming from XP. It's not just 'size' , it's the electrical characteristics that determine whether it's up with the big milled copper/silver coins or down with the thin ladies finger rings. But it seems that manufacturers never speak of the target frequency ( 'corner frequency' / -3dB frequency ) , even though that's exactly what they are measuring on a 'Target ID' scale.

The graphic is showing the 7 frequencies, and their relative strengths for the 4 criteria shown.
So you see the highest freq is good at finding the smallest targets, but isn't that clever at discriminating iron.