PimentoUK

I'm sure some of the more 'entry-level' detectors will have their microcontrollers programmed in assembler. Some may be a mix of compiled code ( often C++ ) and assembler.
For example the popular Microchip IC series:

https://www.microchip.com/en-us/products/microcontrollers-and-microprocessors/8-bit-mcus

https://www.microchip.com/en-us/products/microcontrollers-and-microprocessors/8-bit-mcus/pic-mcus/get-started-now

 

"I’ve always wondered why polycarbonate plastic (LEXAN) has not been used in an instance such as this? That stuffs tough !!!"

The Eqx coil is moulded from a Polycarbonate ( PC ) & ABS blend. My hunch is they used an inappropriate blend - too much PC , or not enough PC.
Plastic failure is not my area of expertise, but I recall stress-cracking to be a characteristic of PC, so if anything, I would speculate using less PC in the blend would be better.

"Also the coil cable is very thin at 2mm thinner than the superbly armored Nokta Simplex coil lead"

I assume the Simplex has a conventional coil, and coil cable. Meaning no electronic amplifier inside the coil. So it uses screened cable for the Receive coil wires, screened cable for the Transmit coil wires, and possibly another single wire for an electrostatic shield connection, maybe followed by an overall shield, then the outer sheath. That makes for a fat cable.

The Equinox ( and I assume the Mandingo ) have a pre-amplifier in the coil, with a differential output. So the RX cable doesn't really need shielding. There are additional wires, for a power supply, and a serial data link, but these can all be thin. The net result is the Eqx / Mandingo has a thinner cable.

The ears are long so that they can easily bend inwards when the bolt is tightened. The bending is spread over a longer length of material, not concentrated over a very short length, like on the Eqx coil ears.

Take a 12 inch plastic ruler. Fix one end, can the free end deflect two inches either way? Yes, easily, it's never going to break the ruler. Now take a 6 inch ruler, and deflect it 2 inches. It's straining the plastic more, and if you repeatedly bent it, you may get some cracking and failure.

I would've liked to see the carbon rod fit INSIDE the end-fitting, rather than the other way round. That would be a stronger solution.

I doubt that site is known at all in the English-speaking world. I discovered it several years ago while searching for info about my vintage Whites Coinmaster 2 / DH.

https://detecteurmetaux2.blogspot.com/2015/06/detecteur-metaux-coinmaster-2-d.html

I'm part-way through restoring it. I have it functioning correctly, I just need to put it back together, then take it for a spin.

It's good to see that you're getting out and finding things.
Do you get much older stuff ? I'm still waiting for you to post up some silver coins, no doubt the Vanquish is capable of finding them.

(sorry for off-topic )
@Midalake:
Did you read my custom Eqx shaft thread? There's some ideas contained in it that may help you get more from your current shaft.

https://www.detectorprospector.com/forums/topic/14805-my-compact-eqx-shaft-project/

Rather than considering it an alternative construction method, I feel it is the only correct way, and gives the greatest chance of achieving a coil that is truly CENTRE-tapped. Methods such as " Wind 29T, bring out a tap, wind another 29T " are guaranteed to result in a coil that has the 'centre-tap' some modest distance away from the centre. The total end-to-end inductance should be much the same for both bifilar winding ,and half-then-half.

As for performance improvements, it's hard to say, without knowing the rest of the oscillator circuit design. Some designs may tolerate 60% / 40% split in the tap position.
Also relevant is the fact there are three coils working together. If they were all closely matched in terms of centre-tap accuracy, the coil as a whole would be more consistent.

I found it modestly interesting, from a technical viewpoint.
If anyone is making this coil, I suggest winding the wire bifilar, that is two wires together. So for example the large winding would be made as 29 T of two wires together. Then join the 4 wire ends together so they function as a centre-tapped coil.

My only old Whites machine is a T/R from the late 1970's , so a league away from BFO machines and quirky coils like this.

Carl and George's geotech1.com forum would be a place where this info may be of interest, (though I've observed that BFO tech gets little mention.)

https://www.geotech1.com/forums/forum.php

With those resistance values, it appears that your 6.5" coil is probably a working coil for SOME machine, just not your GB2.

Do a density test on it. That will give a decent indication of whether it's plated brass, 9/10 carat, 14 or higher.
The method ( copied from elsewhere ):

A ) Place a small container of water ( 20 - 50 cm3 ) on your scales, and 'Tare' the readout to zero.
B ) If you're wanting the weight of the item, place it alongside the water container, and take the reading as indicated.
C ) Using monofilament fishing line / polyester sewing thread / very fine wire, lower the item into the water, so that it is just submerged, and not touching the bottom or sides of the container. Make sure there's no air bubbles attached. Take the indicated weight reading.

Reading C is the weight of the displaced water, which, because water has a density of 1.00 g/cm3 , it's also the volume of the water in cm3 .
To calculate the density, divide the weight in reading B, by the weight in reading C.

So for example, an unmarked silver finger ring: weight = 9.50 grams. The volume = 0.92 cm3.
The density calculated as 9.50 / 0.92 = 10.33 g / cm3 which is typical for Sterling Silver ( tech data usually gives a figure of 10.36 )

Reference densities:

Copper 9.0
9ct 10.9 to 12.7
14ct 12.9 to 14.6
18ct Yellow 15.2 to 15.9
18ct White 14.7 to 16.9
22ct 17.7 to 17.8
Sterling Silver 10.2 to 10.3

The Deus 1 also has the option of displaying a Polar plot ( of target ID vs. amplitude ):

http://www.amdtt.it/2013/01/deus-analisi-delle-funzioni-segrete-della-versione-2-0/

And there's also the two AKA Signum machines, which are MF and have some 2D graphical capability.

Diluted lemon juice, about 5:1 thru 10:1 would be a simple recipe. Brush regularly with a soft brush, like an old toothbrush.
If you want slightly more 'pro' and less 'kitchen' , use citric acid powder, diluted appropriately ( I can't say what mix ratios ) Citric acid powder is used as a cleaner, and also in home brewing & cooking , if that helps find a supplier.

Your mystery coin/button may be a weight.
If it were my find, I would give it a weak acid soak to remove the patina. Then evidence may show itself, for example makers marks, certification marks, etc.

European here.
You're looking for your Roman coins on ploughed/plowed land ? The Roman coins are there to be found because of the ploughing, bringing ( some of ) them within detection range.
A deep detector is not your primary weapon. .. one that can discriminate out iron ( or audibly allow you to distinguish it ), pluck out non-ferrous from among iron, with reasonably fast recovery, is what you need. Your Eqx is going to be just fine.

The hole is curious in itself.
Coins pierced in order to thread a lace etc through them would have a larger hole.
Coins pierced to 'void' them, for example demonetised ones, usually have quite obvious punch marks, usually near the centre.
A forgery may be tested by various means, scraping, filing, punching, bending; so it may be there for that reason.

Any idea what metal it is ? The dark patina is flaking off, not typical of silver tarnishing. But there's no obvious green verdigris type deposits, that a brass/bronze coin would have.

Europeans to the rescue?
The mystery coin is 'copy' of a Mary Queen of Scotland coin.
It reads: MARIA DEI G SCOTOR REGINA on the obverse.
( Mary, by the grace of God, Queen of Scotland )
The original coin would've been a gold coin, something like this 60 Shilling / 3 Scottish Pounds:

https://colnect.com/en/coins/coin/100043-60_Shillings_3_Pounds_Ryal_60_Shillings-1542~1567_-_Mary_Queen_of_Scots-Scotland

... or the smaller 30 shilling piece.

Whether it was intended to deceive ( maybe it was gold plated? ) or just a replica, to be used as a lucky token, or as a gaming piece, I don't know.

But it's worth looking into.

A bottle-diggers probe is certainly one possible tool/technique to consider. You could probably make your own, if you had some engineering skills. 1/8" diameter spring steel, braze a 'ball' on the end slightly larger than the wire. Search online for home-brew manufacture.

Also, using a detector: Use non-motion mode, with a large coil, with cache-hunting technique. Hold the coil 15" / 40cm above the ground, and walk slowly, holding the coil steady and level. With subtle height adjustment, the machine can be brought to the threshold, and very small changes in signal can be heard.
Good machines for this could include the Tek T2 / Fisher F75. The Equinox is OK, the self-calibrating pinpoint threshold gets in the way a bit.

What would these bars be buried in? That's a very important question. Mason/Kilner jar with steel lid? Steel box, like ex-army ammo box? Plastic food container?

I wore through the tip of my original 'Mark 1' Propointer many years ago, and have since been applying a 30mm ( 1.25" ) length of heatshrink sleeve to the tip. Dirt cheap, they seem to last a useful enough time. I removed the pointless 'sifter blade' , the heatshrink then fits properly. If it feels a bit insecure, it's possible to remove it, apply some Evostick / whatever adhesive and glue it back on.

Regarding the battery life:
I've used lithium rechargeable PP3's, and they last a very long time. They are basically two Li cells in series, with protection / charge control electronics internally. So they're 8.4 Volts freshly-charged, probably near 7 V when they 'switch off' .
I used EBL brand, they're 600 mAh capacity. They are commonly sold on eBay and Amazon, and are often sold with the 'special' charger as a bundle. ( I skipped that, just bought 2 batteries and bodged/kluged a charging setup ).

EBL website:
https://www.eblofficial.com/collections/9v-battery-with-charger

I always thought the Equinox single frequency options ( 5/10/15/20/40k) were sub-optimal, so it's disappointing to see the same selection used on Mandingo.
The frequencies should ideally be a fixed ratio apart, and evenly spread over the full range.
So more correct values would be:
5 kHz / 8 kHz / 14 kHz / 24 kHz / 40 kHz
or
5k / 9k / 15k / 25k / 40k if you want 'rounder' numbers.
The relevant difference is the big gap from 20k to 40k is filled, and the too-small step from 15k to 20k is expanded. This may make the machine have a better nugget-shooting freq selection. Other differences are subtle; the choice of 8 kHz matches that of many high-medium conductor detectors, like the Tek Greek-series.
As Eqx/Mandingo can generate absolutely any freq in the range, there's always the option of more choices, in which case:
5k / 8k / 12k / 18k / 27k / 40k
would be good. Plus, being a premium product, Mandingo ought to have more choices than the Equinox.

Best guess, based on Deus 1 coils:
The same transmit coil is used for all modes, regardless of frequency choices. So the Inductance is fixed.
Inductive reactance, XL = 2 * pi * f * L
notice it increases with frequency ... halve the freq, the reactance halves. etc.
Current through the TX coil is: I = V / XL
where V is the amplitude of the ( assumed sinewave ) transmit voltage signal.

So, if you lower the frequency of the transmit waveform, the current through the coil increases. This increases the battery drain.

XP have taken steps that mitigate some of this, by using a more complex transmit signal ( DeepHC & Dive ), that has less low-frequency component , but it's still a power-draining choice.
See this thread:
https://www.detectorprospector.com/forums/topic/18707-not-much-chat-about-multi-frequencies/?do=findComment&comment=198887

It also affects other selectable freq machines; NokMak mention it in the Impact manual, for example. No doubt the Deus1, and the Equinox run at 4 or 5kHz will be affected by it.

I use some 'sport' earpieces, that have the hook going behind the ear to secure them, but the speaker element is 'large' ( actually 14mm diam ) and simply points at the ear canal, and doesn't go into it. They seem comfortable for long-time use.
Sorry I can't come up with a brand/model , but based on the description, you may be able to find something similar.

It's nice to find big silver, even if the silver quality is lacking. I've not found many half-crowns myself, and I'm sure all were 50%, the older Sterling ones have eluded me so far.

If you didn't know, 50% silver coins clean up well with a soak in a weak acid solution. An example being diluted lemon juice, approx 5 : 1 dilution ratio. Brush with a soft brush occasionally.

Correct, it's not discussed there.
I don't actually know what the difference between the two is. I was under the impression 'subtractive' was the 'normal' MF technique, and so the mention of additive intrigues me.

Suffice to say, the designers think it's best for the particular circumstances, so just get on and use it.

Dive mode is a multi-freq mode that's heavy on 4.8 kHz, so it's not going to be all that hot on 'low ID' targets.
Presumably the designers chose the 4.8k / 14.3k frequencies as they are less affected by salt water than a higher-freq mix.

Here's the freqs used in the various D2 modes:

https://www.detectorprospector.com/forums/topic/18707-not-much-chat-about-multi-frequencies/?do=findComment&comment=198887