PimentoUK

Quote:"One thing I might add is a mineralisation meter, like on the Fishers. Not sure if that was mentioned" Yes, I posted some thoughts earlier in the thread about using the '88' display to show mineralisation level: earlier post

Anecdotal evidence seems to suggest the single-frequency modes on the X-Terra Pro perform better than the similar modes on the Equinox, particularly on a wet beach environment. It seems likely the Equinox had most of it's R&D put into multi-IQ, and the single-freq modes were provided as an 'easy to include' addition. Whereas the the X-Terra Pro only has single frequency modes, so no doubt some design thought was put into their operation. SO, it would be nice if any Equinox update could include improved single-freq modes, based on X-TerraPro "know-how".

There is a larger coil made for the GB2, similar shape to the 6", but about 10" long? Perhaps it may be worth looking out for one of those. As they are official Fisher products, there's a good chance they have geometry that's deemed correct for the machine. Putting a round 15" DD on a 72 kHz machine, for example, may just prove disappointing ( big coil says 'big targets' , 72 kHz says 'small targets' ).

You should register with the Geotech1 Forum, where you will find an abundance of info about coil building: Geotech1 forums Unfortunately, the GB2 is one of those "difficult" coils. The combination of high operating frequency, and internal components ( tuning capacitor etc ) , and the fact no-one seems to have reverse-engineered one, means your chance of success are low. I think the GB2 is not the best choice for beach detecting, due to its high operating frequency, and inability to handle the electrically-conductive salt-water sand. It would be better to buy a new machine dedicated to beach hunting, preferably with some degree of water-resistance as a feature.

Quote:"It is [an assumption], but only to a very small degree, because the ground was encompassing most of the field with each coil tested." I've no idea what "encompassing" is defined as, I would assume even with the coil pressed on the dirt, it would only encompass half of the field, the half below the coil. But anyhow, I've located some ground pickup measurements I did on my Fisher F75 11" x 7" DD coil. This behaves much like a 7" coil ( long, narrow coils tend to have their characteristics dominated by the 'narrow' dimension ). Assuming your 'standard' coil height is 1 inch, and you state the 11 inch coil was raised 2.5 inches above this, to 3.5 inches: I'll convert that to 25mm and 87mm metric. My measurements show a ground signal level of: 25mm ... 7.6 mV 87mm ... 2.8mV that is a drop to 37% of the signal at 25mm height. I would expect an 11 inch coil to be less affected proportionally by such height changes than a 7 inch one, so perhaps a 45% to 50% drop would be an estimate? This then permits a target signal 45/50% weaker to be picked out. This roughly equates to 15% more target depth ( ie coil to target depth ).

Quote:"The raising of the coil ... wasn't a "significant" flaw, as the vast majority of the field below the coil was still in the ground for each coil." That sounds like a very hand-waving guesstimated assumption to me. Not backed up by any technical measurements taken on a real detector, or any ( difficult ) mathematical modelling of search-coil behaviour. Like anything technical related to detector operation, the truth is never straightforwards. Ground signal does drop off as the coil is raised .... but not anywhere as severe as the target signal drops off. And when a coil is very close to the ground, the ground signal behaves rather unexpectedly, and can actually 'plateau' or fall in level. But ... the phase angle of the ground signal also varies too: raise the coil 20 inches, you'll get a huge phase shift from 'ferrite-like' to 'salt-like'. It's really the "wobble" in ground signal that causes trouble to a detector. Some perfect uniform flat ground, and a perfectly swept coil, would give nearer air-depth results. If you're comparing different size coils, are you comparing them at the same height? Would it be more correct to compare a 10 inch coil at 1 inch height, to a 5 inch coil at 0.5 inch height, for example? Or do you keep a fixed 1 inch, as that's how you would use a coil in real world hunting? It's also worth noting that EMI pickup is coil height dependant. It seems that the ground provides some degree of shielding, perhaps it depends on whether the EMI is vertically or horizontally polarized.

How coils pick up a target signal, how they pick up the ground signal, and how they pick up EMI, is a complex issue. And it varies from one machine/manufacturer to another. So it's important to state that this is a test of the Legend. Plus, it's probably wise to state what revision of firmware it's running, as performance could well vary as a result of this ( in the past and for future revisions ) Regarding:"I don't see how a preamp in the coil, or a 'security chip' in the coil, would affect the coil's susceptibility to EMI and ground impedance" The pre-amp DIRECTLY affects pickup of targets, the ground, and EMI. So for example if a 5 inch coil has a pre-amp gain of 20 , and they make a 10 inch coil with a gain 14 ( ie. 0.7 x the small coil gain ), then: The larger coil will likely pick up about 2.5 times the EMI, multiplied by 0.7 = 1.75 times total. So it still picks up more interference, but not as bad as would be expected ( based on typical 'simple' detector behaviour ). Likewise, the larger coil picks up a stronger ground signal. This is part of the reason the manufacturer may choose to make the pre-amp gain lower. And on the subject of ground signal pick-up: Quote:"By saying "going deeper", I meant I could raise the coil by that amount off the ground and still get a good repeatable tone." This shows up a significant flaw in your tests. If you raise your coil, not only do you reduce the target signal, you also reduce the ground signal. Considering a primary function of the detectors circuitry is to pick out the ((target)) signal from the ((target plus ground)) signal, changing both target and ground signal is not equivalent to changing just one alone ( by burying the target deeper ).

Quote:"I didn't post what detector I'm using, ... I think the results would be similar with any detector and its various coils" The machine used IS important. Many modern machines, such as the Equinox / Manticore / Deus / Deus2 ,and more, have electronics inside the coil. The Equinox/Manti have a pre-amplifier, plus a 'security chip' that ( as well as security) identifies itself as a "15cm circular DD" etc. The Deus1 & 2 have half the detector in the coil. As a result, you should not expect them to behave the same as a simpler detector with 'plain' exchangeable coils. For example: The Equinox small coil may have a higher gain pre-amplifier. The control box may read the coil ID data, and implement a higher sensitivity or gain , to give an accurate "depth gauge" readout, or to compensate for the inherent lower signal levels produced by a smaller coil. The Deus doesn't even have to use consistent coil winding inductance/resistance values across the range of sizes, as both the transmit and receive electronics are integrated. As this thread is about the Legend, I can't say what N-M have done with their coils. There may be X-rays out there ( I'll check "Strick's" thread later ) that give some clues?

It could be that they put more design effort into the XTerra Pro's single freq choices than they did on the Equinox. That is to say ... the Equinox single-freq options are a bit basic. Probably because they are not the "main act", Multi-IQ , which no doubt got plenty of development work done on it. There are doubtless some tricks that can be performed to improve salt beach performance of single-freq machines - the NM Racer machines were generally thought to do unexpectedly well on salt. I recall some technical discussion on the Geotech1 forum: the Racer had a variable-gain pre-amp circuit, that was automatically controlled by the micro, and this enabled it to always run at optimum ( maximum ) gain, regardless of the wet ground signal level. Such a process can easily be replicated in an Equinox/Vanquish/XTerraPro, as it's pretty much all done in software.

It's interesting that you've found the XTerra Pro to perform well. It makes me wonder what the "design strategy" for it was. Take an Equinox, and make a stripped-down cheaper version of it.... or make a detector that behaves like the X-Terra range. No doubt either is possible, the microprocessor brains is surely capable of plenty more that what the finished product does.

I think a pre-owned Equinox 600/800 would have been a wiser choice. The Xterra Pro is basically an Equinox with the best features removed. I use a '600 , and find it an excellent all-round machine, though it does have its 'negatives' as you are doubtless aware.

It's definitely old. It does resemble Tombac, that has corroded heavily. The makers mark ( touch mark ) is three alternating keys, inside a beaded/dotted circle. Similar items for guidance: PAS spoon1 PAS spoon2 If you fancy browsing through thousands of spoons, this link should work: lots of spoon

"Wouldn't square cuts also have the same benefit?" Yes, but .... even if you laid the square holes in rows, and offset each alternate row by half a square, you would still end up with a pattern that was not 'uniform'. There would be a weakness in one direction, a strength in another. Compare this to the 'hexagonal close packed' arrangement, that round holes and hexagons give. Furthermore, the internal corners of a square hole are an engineering weak point. They would need to be radiused in the corners. And the same applies to hexagons, to a lesser extent. Laser-cut holes have a rough finish on the cut surface, which is a weak point for crack formation - all cracks start as micro-cracks, and grow. So a smooth cut, polished surface would be the ideal one. Also, consider the fact that square holes have a diagonal dimension 41% greater than the face-to-face distance, so they may let objects through that you would like to trap. A hexagonal hole has a corner-to-corner dimension only 15% larger than the face-to-face distance.

Bearing in mind these holes / slots are CNC laser cut , I believe the hexagonal hole is slightly quicker to cut than a circle. Hexagons also have a slight technical advantage, they can be packed closer together, without getting the problem of the metal getting too 'thin' from hole to adjacent hole.

Plenty of familiar British bits there. The pot lid is for cherry tooth paste: toothpaste lid

"I doubt anybody would complain if you did a second post with a few close ups ???" I agree, there's some cool bits there, many of which are familiar to us UK detectorists. Re: the two weights below the clay pipe stems: The rectangular one with the annulets design is an Apothecaries weight, similar to this example: Apothecaries weight The dimensions and weight would pin down the exact weight it's supposed to be. The circular weight is a coin weight. S and P indicate shillings and pence, the I and 3 show it's One shilling and Three pence, which would be a quarter of a (five shilling) Crown, an uncommon denomination. V R will indicate Queen Victoria ( Victoria Regina ). Some related reading, & see the comment at the bottom: Coin weight

I looked at the link, and saw those attractive photos, with the old maps etc as the background .... they seemed familiar. The answer is at the bottom of the page: "You have no authority to use my photos and I will have my solicitor contact you. Belinda Downie Friday 17th of March 2023" Belinda is a well-known coin dealer ( Coinworks ) , Mr Paulsen has just lifted her photos wholesale for his article.

@Jim Hemmingway I don't use Chrome, but here is a website guide to turning on/off scripting in Chrome: https://www.lifewire.com/disable-javascript-in-google-chrome-4103631 disable-javascript-in-google-chrome Other options are: Use the most recent version of Chrome, that works OK with your version of Windows ( if you tell us what Windows you have, we can work out what Chrome is suitable ) Using an additional different browser ( you can keep the Chrome going ) Suggested choices are Mozilla Firefox, and Opera.

I didn't bother detailing it all, especially as it would be irrelevant to iPad type folks. But seeing as you've kinda done it anyway, here's my version: Open a new tab, and type in About:config in the address bar. Then 'Bookmark' that page, so you don't have to fanny about typing it every time, simply choose it from your list of bookmarked pages. In the about:config page's search box, type 'ja' ( without the quotes ), and at/near the top of the ja..... options, is 'javascript.enabled'. Double-click will toggle it's 'Value' true/false ( ie. On/Off ) Keep the about:config page tab open, so it's there ready for when it's needed. I'm sure there is a Firefox browser add-on that simply gives you a button for scripting on/off, which may be useful to some people. [ it used to be a drop-down menu option on Firefox at one time, under 'Options', but in their wisdom, they broke it.]

Just thought I'd throw in my 2 cents: As Steve knows, I have an outdated PC, which struggles with some things. I've had this 'thin wide useless text box' problem for many months, since September, perhaps. It can be crudely resolved by turning off Javascript. I then get a full text box, but zero in the way of top-menu niceties, like basic font size/colour/italics/bold etc options. And external html links don't auto-parse, so just appear as plain text. As 'BB-Code' is no longer supported here ( on new posts ) I have to use my dodgy html skills to get some features to work ... or wait until I get on a more modern computer, and edit the post. Turning off Javascript is a bit of a fiddle .. some browsers have it as a simple option on the top menus. Firefox is a pain ( these days ), though I've got it sorted out. Update: for what it's worth, I turned on the 'web developer' debugging feature on my Firefox. The scripting errors it spits out in the area of the 'posting box' all seem related to 'jquery' and 'jqmigrate'., which looks new-ish, I don't recall seeing it before: JQMIGRATE: jQuery.fn.bind() is deprecated JQMIGRATE: JQMIGRATE: jQuery.cssProps is deprecated

Dropping onto a hard surface is bad news for pinpointers. The ferrite rod has probably cracked, in which case, it's terminally damaged, unless you are patient and skilled. But even with a rebuilt search-coil, it may need recalibration - which is the tricky bit. The earlier black Propointers had a 'master calibration' function built into them. The AT doesn't; it may be that it's done when the software is burnt into the microprocessor. But there's nothing the user can do. Additionally, the vibration-motors are fragile, and they can break out of their retaining clip.

I always utilise my detector in a boustrophedonic fashion. It's a scientific fact that boustrophedonically surveying the terrain is optimal. https://en.wikipedia.org/wiki/Boustrophedon The concept of metal-detecting with drones came up on another forum once ( Geotech1, likely ). I pointed out the XP Deus could probably be persuaded to operate at long range, if the 'remote' unit was modified to use a high-gain antenna ( parabolic dish / waveguide 'cantenna' / Yagi array), the hard bit was getting the drone to fly close to the ground but not too close.

Please repeat the question in French , perhaps we can translate your words better. Repeter le question en Francais, s'il vous plait.

I've tried to track down which model that is. It appears to be this one, but modified: 'Gold hunter smart': https://uigdetectors.com/gold-and-metal-detectors/gold-hunter.php?la=en Notice on this guys machine it has an additional 'homebuilt' box with three 'controls' and badly-fitted knobs, stuck onto the top of the case? Also, the cheesy 'radar dish' antenna has been removed. They suggest 3000 US dollars retail price. I wonder if someone even more enterprising than GER is buying these devices, adding 5 dollars worth of extra 'electronics' and re-selling them at an even higher price, like 6000 dollars ?

To create a shorter distance between grip and elbow cup, an alternative is to drill a new hole for the control box. It can be moved back 20mm comfortably, which is the equivalent to moving the elbow-cup forwards one position. Up to 23mm back is possible before the original hole becomes uncovered and it starts looking less pretty. The hole diameter is 9.0mm ( the same as that for both elbow-cup holes ), I recommend using a drilling guide to make the hole, eg. an aluminium / plastic plate with the correct size hole in it to ensure the drill bit stays on-target. I think drilling the hole slightly under-size, and taking the time to open it out to 9.0 by hand-filing is worth the effort. This then allows you to make sure the hole is centred exactly right. Something like 8.0 - 8.5mm would seem appropriate. For you US folks, 5/16" is 7.94mm; 11/32" is 8.73mm.