Upgrade Question... Due to Coil Size Limitations

[FooserPaul]

Hello ALL!

Will the lack of larger coils cause us to think about upgrading?

If so, due to wanting larger coil(s)... what would your choice be?

Paul

 

[nero_design]

I think the X-Terras are designed to be as light and trouble free as possible. Most people are easily annoyed if they find out they need more than one coil to enable them to detect for what they want. The frequencies selected for the X-Terras were carefully considered by Minelab before they released them. Some coils are better suited to Native Gold in mineralized ground (High Frequency @ 18.75khz) and the very low frequency coils (Low Frequency @ 3khz) are good for Silver etc. The average user only needs the 7.5khz coils which come with the detector. This was picked as the optimum all-purpose frequency. The size of the coil can assist the user further for a number of reasons but larger is not necessarily better. If you want a large coil to scan more areas at faster speeds, then you may be moving too fast to appreciate and notice the fainter signals.

When you use a smaller coil, the field that the coil emits tends to be very strong. But the area that it transmits to is close to the coil. It's a bit like a thin coating of paint. Small coils like the 6" DD are extremely sensitive to VERY small targets. If the coil emission is too strong, the electromagnetic field will not penetrate the soil as far in many instances (especially if it's mineralized or contains salinity) and the field will collapse in on itself and cause excessive false feedback etc. That's why the 6" coils are not as suitable for scanning larger areas of soil as a 'normal' sized coil. They can penetrate deeper but this blade-shaped field is very narrow so a user can easily miss targets if the coil is not passing directly over the item at the correct speed. That's why the 6" coils are more of a specialist coil for very specific targets or environments. Their primary field is deep and narrow but the general field is very close to the coil and you won't ever see things that the coil passes directly over unless the "blade" touches the target.

Medium/Normal sized coils are ideal for most uses and are suitable for medium to larger targets. That includes coins and chains or jewellery etc. The field is not as thick and intense as on the smaller coil but it radiates out further from the disc... so there's more control in how the field will return a stable signal to the detector without being oversensitive. These are easier to use for the majority of detectorists since they can casually detect a beach, a park or a paddock with these coils and (generally speaking) the experience is usually a simple affair with few complications and larger areas can be detected in less time. The signal is usually more stable and less erratic.

Now a larger coil would allow a person to cover more ground per sweep but the added weight, insulation, resins and plastic will offset the balance of the coil somewhat and the signals will become weaker at depths not near the surface. There will be less ground penetration unless a little more energy is used to drive the coil. You can get a digital-to-analogue booster for the X-Terras from third party suppliers and this will increase the fidelity of the fainter signals (not just amplify them). But a larger coil on a single frequency detector like the X-Terras won't add any advantage that I can see. In fact, you'll get less penetration (less depth) if larger coils were available. Anything beyond the size of the 10.5" DD would not guarantee better results on the whole. You are using AA batteries too, not heavier Gel-Cells etc.

If you want more penetration, you might want to consider other models in a higher price bracket than the X-Terras with BBS technology or similar.
Those professionals hunting nuggets etc with extra large 22 inch wide super-sized coils are not really getting any advantage over smaller coils and (something worth noting), large coils like those would be useless on an X-Terra because they are designed for flat areas where the user doesn't need to navigate around obstacles and rocks etc. The smaller the coil, the more versatile it is. I suspect that's what Minelab were thinking when they announced the numerous X-Terra coils for the consumer. I personally wouldn't want to see another coil of any size for the X-Terras unless it was an improvement over an existing coil (ie: to replace one already available).

Just my thoughts.

Cheers,

Marco

 

[BarnacleBill]

To be honest, I don't understand your question.

Does "upgrade" mean buy a more expensive detector? i.e. Etrac, DFX etc.

Or, buy a different detector that has larger coils, simply because it has larger coils?

In regard to larger coils for the X-Terra, I hunt beaches with miles of open sand that look like this:

[attachment 110856 north.jpg]

On first thought looking at the area to be covered, the thought of a 15 inch diameter coil may seem appealing. But.....when I go to hunt the beach, because of distance & gas costs, I go for the whole day. That means swinging a detector for 8 to 10 hours with two 10 minute snack breaks & a 20 minute lunch break.

When comparing the standard coil weight to how the 3KHz feels when attached, it becomes apparent that a 15 inch 7.5KHz or 3KHz coil is going to make the X-Terra very nose heavy. To the point in my case it may lead to less area being covered because of fatigue. So I for one am very ambivalent about a larger coil on this detector as I believe the practicality versus theory should be considered.

HH
BarnacleBill

 

[xwyokid]

Honest question. For me, I'll just take my time. I don't see getting rid of my X-70 for any reason,( I purchased it because of the tones and its weight) especially the way the economy is.

 

[FooserPaul]

I was just posing a simple question...

"Would you ever see the need to upgrade, buy a different detector, due to not having a coil sizer larger than the current selection

Just trying to have a friendly mind melding session

Paul

 

[David]

I am reposting this again from another thread because it is relevant in answering the question asked here by FooserPaul. Good points Marco and Bill and a bigger 15" or 18" DD round coil for the X-Terra 70 is not the answer in your eyes BUT how about a lightweight (full)8"x18" DD rectangular or (full)10"x18" DD elliptical would be great for fast coverage on beaches and fields for the X-Terra 70. And by the way the round 15" WOT DD works on the Musketeer Advantage fine with AA batteries without taxing on performance and increases performance on coin size objects over smaller coils.


I have a GP 3000 with a NuggetFinder 25" SL mono, 20" SL XP DD, and CoilTek 20"x40" DD. Yes you are right Nero BUT very poor discrimination and I would be picking up all sorts of trash and junk looking in farmers Fields and Grassland. Maybe the GPX 4500 has much better discrimination than my GP 3000 ??

Yes a 15"x12" from Minelab for the X-Terra 70 OR release the rights of the patented chip to a aftermarketer(like Detech or CoilTek) to make a coil, for a cut(%) in the profits. I have contacted Minelab in Australia and told them I want a bigger coil for the(my) X-Terra 70. Does not look like they will but they will keep my suggestion on file. My number one choice in size would be a 12"x24" or a 8" or 10"x24". Maybe a 8" or 10"x18" as well is also a good size. Think about even a lightweight (full)8"x18" DD(elliptical or rectangular) would be great for fast coverage in large Fields and Grassland !!

(I already have DOC's Swingy Thingy and also the Swing Eze is made too just in case or put Minelabs "bow knuckle" on the shaft and use a bungee on it only if necessary.)

This is your answer FooserPaul: My solution to the big coverage problem was to buy a Musketeer Advantage and I am going to get a CoilTek 15" WOT DD for it. There is a WOT made for the Eureka Gold as well. I thought about getting an MXT or DFX with a 15"x12" SEF(also a 18"x15" SEF and 18" round EXcelerator is made too) or a F75 with a 15"x12" SEF as well. BUT NOT a BBS or FBS machine because they search very, very slowly and defeats the whole purpose of using a large coil for the most coverage in a day in farmers Fields-homesteads-Grassland(and large vast dry sand beaches but on wet saltwater sand a FBS or BBS machine could be used for more depth..

My two-bits.

 

[David]

Look at this one from Whites. Why couldn't Minelab make one for the X-Terra 70 in this size or in 8" or 10"x 18" DD would be a better choice for a size.
Eclipse Deepscan DD 1400 Search Coil for DFX

 

[TomB]

I was just posing a simple question...

"Would you ever see the need to upgrade, buy a different detector, due to not having a coil sizer larger than the current selection

Just trying to have a friendly mind melding session

Paul

Yes, you poised a simple question. And I think you were given very good answers. And I don't see anything that could be considered unfriendly. Strange post. TomB

 

[BarnacleBill]

OK now it's phrased a little clearer for me. My mind's already melted into a puddle!

I have other brands/models of detectors with 10.5 inch coils. In using those coils it's clear to me that I don't want to go to anything larger because of the weight factor. Those detectors come in several configurations with the weight balanced at different points.

HH
BarnacleBill

 

[hogedog]

Not sure but I don't think anyone is looking for comfort in reference to balance, when searching for deep stuff. Would I like a larger coil, yes at times I would like the option. Is a DFX an upgrade, I don't think so. I am happy with my XT70 and know what it can do with the available coils. When I bought it I knew what was available in reference to coils. It does all I want at this point with what is available. How often does anyone dig a coin more than 12 inches? My soil and conditions may be much different than all others but, I am pleased with what I have. In my opinion there is no better "all around" detector than the 70. Be it a 9 inch coil or not. Not looking for an argument or anything, I'm just happy with what it does. For deep stuff I use a Garrett 2 box, other than that I don't think I need anything. Perhaps I'm wrong.

JFK