Hot Or Not? Differences In Coils

[phrunt]

So, let's forget about Nugget Finder, it was just a recent example and I can't be bothered scrolling through history of facebook groups to find a video where a Sadie is not calibrating for some person and other Sadies like mine do calibrate to provide you with a video of an example of an inconsistancy, it doesn't mean that much to me,  and get back to the premise of the question, which was are some coils hotter than others of the exact same coil, as when hand making coils no two coils are exactly the same with their windings so it would be feasible to think that.

 

[AussieMatt]

There's been people swear they've had "hotter" coils &/or detectors for years.

To be honest I've never witnessed a coil (or detector) that is significantly better than the same size/model/type unless one being compared has been faulty. I can't really see that any difference (in coils or detectors within their tolerances) would be so significant that people would even be able to tell, as everything should be made to be within the acceptable tolerances? 

Obviously some do slip through Q.A (I would class out of spec coils/detectors as faulty though not less hot?).

Has Nugget Finder actually come out & said they've ceased production due to manufacturing inconsistencies or is this just speculation? All I can find is that they're currently ceased while new coils are being made/tested that will suit Ultra Fine (AF E1500) & modified former GPX models.

I don't know but to me this doesn't mean the NF Evo's were inconsistent, overly faulty &/or out of spec (for the machines they've been made for) but rather an opportunity has presented for NF to improve on them by making coils more in spec to suit the AF E1500 Ultra Fine mode + modified detectors as well as the current detectors they were originally made for?

"Continual Testing and Development of new products guarantees the coils you buy today are matched perfectly to the latest Gold Detector Technology."

[phrunt]

46 minutes ago, AussieMatt said:

Has Nugget Finder actually come out & said they've ceased production due to manufacturing inconsistencies or is this just speculation? All I can find is that they're currently ceased while new coils are being made/tested that will suit Ultra Fine (AF E1500) & modified former GPX models.

Thanks for your comment Matt, very good reply to my query.

You're right though the reason they've ceased appears to be they're making a new range to suit these newer detectors or modified detectors that benefit from slightly different coils to their existing ones.  

The inconsistences are part of the problem with the older ones though, some calibrate on the Algororce fine, some don't of the exact same coil model.  If they all calibrated fine then there would be little need to make new coils at least as far as the Algoforce is concerned, so the inconsistencies are involved in the new coils being required at least when it comes to the Algoforce, I'm not sure about the modded GPX's, I know nothing about them.  Nugget Finder hasn't come out and said much, other than they're making new coils and they'll suit the Algoforce and modded GPX's better and they've stopped making the existing ones like the 14x9 and other sizes.

It's certainly not intended as any sort of beat up on Nugget Finder, they were just a recent example of coils that can differ in the way they work between one coil and another of the same coil with the calibration process of the Algoforce used as a testing method, so let's make it more generic on brand of coil and forget NF was ever mentioned.

I'm sure if we had a big bunch of coils on hand from any brand and tried to test them all the same way there will be some that exhibit the same behaviour, but that's why my query come about some coils perhaps being hotter than others with these differences, such as would a coil [insert brand name here] that calibrates fine on the Algoforce perform better on a GPX 5000 than one of the same [insert brand name here] coils that fails calibration on the Algoforce being used on the same 5000, or are the differences not enough to change any results at all with the 5000 as it's still perfectly matched to that machine.  Obviously when it comes to the Algoforce the one that doesn't calibrate won't work as well as the one that does. 

[PhaseTech]

I believe there may be very slight differences in coils (of the same make/size), but more so with older coils. Coils that were developed with the stock 5000 in mind, had much stricter requirements, and if there's any differences, it would be very marginal. Also once the detector is tuned properly for that particular coil, any differences would be non existent. E.g. if Coil A was a little hotter than Coil B, chances are coil B would run a little smoother so the Rx Gain and other tweaks could be bumped up a bit, basically bringing coil B up to the level of coil A. 

But, everyone has their favourite coils, and my favourites are what I gel with for a number of reasons, not just sensitivity. A coil needs to feel good when I swing it, run stable, minimal cable noise, minimal flex, not be too heavy for its size etc etc. If it ticks all these boxes I quickly get a good vibe from it, and when it finds me some gold, it's a keeper and goes in the kit. 

The Sadie Mk2 will be out soon, so looking forward to giving it a run on the E1500 and also on the 4500 and see how it goes. 

 

[flakmagnet]

1 hour ago, PhaseTech said:

Also once the detector is tuned properly for that particular coil, any differences would be non existent. E.g. if Coil A was a little hotter than Coil B, chances are coil B would run a little smoother so the Rx Gain and other tweaks could be bumped up a bit, basically bringing coil B up to the level of coil A. 

6 hours ago, AussieMatt said:

Obviously some do slip through Q.A (I would class out of spec coils/detectors as faulty though not less hot?).

PT and Matt your points make a lot of sense. Isn't it correct that coils are made to operate within a range of tolerances and in those tolerances the detector and the coil work well together. 

[RONS DETECTORS MINELAB]

Looks like we will be seeing some new innovation coils, so glad this has come about. I look forward to doing some testing of the new technology when it’s available.

[phrunt]

6 hours ago, PhaseTech said:

I believe there may be very slight differences in coils (of the same make/size), but more so with older coils. Coils that were developed with the stock 5000 in mind, had much stricter requirements, and if there's any differences, it would be very marginal.

Thanks so much for your reply, I remember back to the QED and it's selection of pulse delays by way of the mode setting, and some people were able to run coils in Mode 1 which at the time was 7.5uS and others with the same model coil were having to run at mode 2 or 3 jumping up to 8 or 8.5uS to get it stable, I thought a lot of that had to do with ground but then again even in the air some people were unable to get certain coils working on mode 1.

My 14x9" EVO which is a personal favourite coil of mine always worked on mode 1 on my QED, and again calibrates fine on my Algo and works well in ultra fine, I've always been happy with that coil, very sensitivie for its size too, I think it's just as sensitive as my Sadie, if not more so plus I get the depth benefit of a bigger coil.

One of the things that QED users liked about the X-coils is they tended to be good coils for us in Mode 1 7.5uS, I don't know if it had anything to do with it but back then early on with X-coils making GPX coils Reg Wilson as a QED Dealer sent a QED to X-coils, perhaps they adapted their coils to run well on the QED at 7.5uS which may be why all mine run good on the Algoforce too (except the Concentric coil)   The QED was too insignificant of a detector in the market to make coil makers take note I guess and adjust their coils for it.

This is my 10" Coil

I too look forward to the new Sadie, I can see me having difficulty offloading my couple of month old one though with the new one on the market!   I will just keep it for my GPX 5000, and should be OK for that, but stewing on that made me wonder if a new Sadie adapted to the Algo would be better on my 5000 too and inspired my initial question.

[Guys gold]

Phrunt On the original theme so to speak on same coil same size I have 2 NF 12x8 coils.On a stock 5000 they work exactly the same ,depth on target with same setting.One coil is early model which measures 3/16 less in overall thickness.Now enter Modified 5000 with the abilities to adjust sample time on each timing”to lengthen the pulses to add more energy to a target.And the front end gain ,that boost the RX signal greatly before it goes threw any gaits ,ie filtering,By adding all these different parameters to the mix.Some coils perform better than others.But the majority of coils if your a bit conservative with the frequency and gain,they can run smoothly.But in the case of pushing the envelope,thing can get noisy.To end this with my rig older 12x8 runs better than the newer one,NF is still the best coils available.

[Aureous]

Since owning an E1500, I have delved into the calibration issue a lot. So far, Ive tested three Sadies, two 10x5 Joeys, two 9 Elites and a Nuggeteer 12x4. Both of the Elites run well and calibrate for UF mode. Best sensitivity by far. Only one of the Sadies runs well, one wont calibrate and the other does but has less sensitivity. Only one of the Joeys calibrates and runs well. The Nuggeteer wont calibrate but is equal in sensitivity to the good Sadie and good Joey.....go figure.  What I have found out though, is that every coil that works well AND calibrates, are all over spec. The standard Inductance value for GPX coils is supposed to be C. 300uH. If you're within 10% of that number, it will run fine. On the coils that calibrate and run well on the E1500, the inductance values are all above 350uH. Coil resistance values are all below 1 ohm, this doesnt seem to affect anything much between them all. 

Re the GB2 coils, I had a couple that were killers. One was a freak from the older Los Banos model (pre FTP ownership) and the other was a rebuilt one from the PMC guys. I still have it, but no GB2 anymore. They used an experimental wire in the original shell and hand made internal wire former. Think I found well over 1,000 bits with that little 6x4 CC coil.