Whites Trx Getting Stuck

[kac]

I had similar issues with the Profind 35. Non wireless Carrot can't go wrong and if it's too small for the pp then use a handfull of dirt over the coil. Better than digging false signals. Can't tell you how many 12"+ holes I dug and almost buried the PF in do die a miserable death lol.

[phrunt]

Yes I've had the same problem with my Pro-Find 35 too, I had it replaced under warranty a few days after buying it for doing this, the replacement was absolutely no better, in fact I thought it was worse so I kept the original and sent the replacement back to the dealer.  I think contacted Minelab in Australia about it and showed them this video, they told me its completely normal

My Pro-Find 35 now spends its life in my cupboard next to my T2's rarely to ever be used for anything other than some testing purposes.  I always thought a pinpointer would be the easiest detector type to make compared to the complexity of the actual metal detectors but it seems it's the product they all struggle the most to make well, the Carrot AT the exception.

[mh9162013]

43 minutes ago, phrunt said:

I think contacted Minelab in Australia about it and showed them this video, they told me its completely normal

Then my Pro-Find 35, when I had it, was acting abnormally, b/c it didn't do that at all.

[Geotech]

What you are experiencing is Earth field effect (EFE). The Earth's magnetic field affects the RX response slightly and as you rotate the coil around the effect varies and can cause falsing. It is more prevalent with pinpointers because there is a ferrite rod in the coil and the Earth field affects the reaction of the ferrite. Theoretically it can happen with any pinpointer but is more prone with high sensitivity designs. I recall when I built the first TRX prototype I used the wrong ferrite and it was incredibly sensitive to EFE, it would go crazy as I waved it around.

[phrunt]

Ok, perhaps my TRX isn't faulty then, as my biggest gripe was with EFE thing, and if that's normal then my only issues are sensitivity level 4 is not usable but I guess it's better to have a hyper sensitivity mode than not to have one so that's acceptable.  The getting stuck thing which all I do to resolve is press the retune button although after doing that I lose some tiny target sensitivity but it seems to mostly happen if the target it hits is a big target, a little pellet is unlikely to cause it to get stuck, in fact it never has on a little target, it's always the big ones.

It's relatively stable in sensitivity 3 but still gets "stuck" sometimes, I'll give it another chance, I've been so down on it I never want to use it although when I have used it I've used it in sensitivity 4 as I bought it to help find tiny gold so I wanted the tiny gold sensitivity.  I'll give it a shot as a coin pinpointer on sensitivity 2 or 3 whichever is most stable and see how it goes.  Maybe I'll find the tip sensitivity useful for coins.  I've turned off the vibration now so perhaps that'll make it a bit more stable, I'm going to give AA batteries are try instead of my 9v.

I don't find it all that difficult to adjust settings on, I've just changed the order so the easy one to change is sensitivity.

I'm sure it's a good pinpointer, plenty of people love it, that's why the price of them when so sky high when they were no longer available, the fear of missing out went wild and people paid crazy prices for them.   I'm just so fussy with pinpointers as the Carrot AT set the bar so high others just don't compare for me.

[mh9162013]

8 hours ago, Geotech said:

What you are experiencing is Earth field effect (EFE). The Earth's magnetic field affects the RX response slightly and as you rotate the coil around the effect varies and can cause falsing. It is more prevalent with pinpointers because there is a ferrite rod in the coil and the Earth field affects the reaction of the ferrite. Theoretically it can happen with any pinpointer but is more prone with high sensitivity designs. I recall when I built the first TRX prototype I used the wrong ferrite and it was incredibly sensitive to EFE, it would go crazy as I waved it around.

So why do some pinpointers do that while others don't (even though they're the same model)? Slight differences in the Earth's magentic field and the pinpointer itself? I remember Steve saying that it's really hard to consistently manufacture coils on a mass scale.

[Geotech]

The TRX has an IB coil which is difficult to make so I suspect minor variations in the coil may cause it. I assume the new ProFind design is IB as well (it has iron ID) and probably has a similar coil design. The 1st-gen Bullseye, 1st-gen ProFind, and all the Garretts are energy theft designs which use a simple mono coil and don't really have the sensitivity to pick up EFE. The F-Pulse has the sensitivity, but uses bipolar pulsing which naturally cancels EFE.

[Guest]

19 minutes ago, Geotech said:

The TRX has an IB coil which is difficult to make so I suspect minor variations in the coil may cause it. I assume the new ProFind design is IB as well (it has iron ID) and probably has a similar coil design. The 1st-gen Bullseye, 1st-gen ProFind, and all the Garretts are energy theft designs which use a simple mono coil and don't really have the sensitivity to pick up EFE. The F-Pulse has the sensitivity, but uses bipolar pulsing which naturally cancels EFE.

GeoTech,

Thank you for this post and so many others like it. You offer genuine insight in detail into things I would never even think about.

Sorry if it is off topic, but if a person wanted the sensitivity of the TRX and did not care about iron ID, what would one have to choose from? Solid and reliable are a must for anyone of course, but the level of small the TRX would get and enhanced directional sensitivity are hard to know up front and make sense of. An engineer’s perspective would be most welcome.

I struggle to know how or where to ask this question, please pardon the intrusion.

[EL NINO77]

14 hours ago, Geotech said:

What you are experiencing is Earth field effect (EFE). The Earth's magnetic field affects the RX response slightly and as you rotate the coil around the effect varies and can cause falsing. It is more prevalent with pinpointers because there is a ferrite rod in the coil and the Earth field affects the reaction of the ferrite. Theoretically it can happen with any pinpointer but is more prone with high sensitivity designs. I recall when I built the first TRX prototype I used the wrong ferrite and it was incredibly sensitive to EFE, it would go crazy as I waved it around.

Carl Moreland ..
here he perfectly wrote the very essence of the problem .. ,, and pinpointer Profind 35 will behave similarly on higher sensitivities ...
  - at a highly set sensitivity, this pinpointer can be more sensitive to the change in the orientation of the search probe in the electromagnetic field of the earth ....
..
  Profind 35 I know how to switch on  in the field..about in the same orientation in which I will continue to search for them ... then it will work the most stable..even when setting a relatively high level of sensitivity ...

it's one way to work at high sensitivity...

 

 

[phrunt]

It's interesting Minelab went with the same design internally as the TRX where they both get the EFE issue, the Minelab is also very close in performance to the TRX when in maximum sensitivity and also has the issue of instability in maximum sensitivity.  The ML has discrimination that I'd never use as it cuts sensitivity even further.  I'll leave the discrimination to the detector which does a better job of it.  I guess Minelab using the same style coil in it's Pro-Find is a nice farewell nod to the TRX.

The Carrot AT is as stable as anything and you can swing it around in the air like a crazy man with no fear of it reacting with the EFE due to the different coil design, it's small target sensitivity is only slightly behind the TRX and ProFind but it remains completely stable in it's highest sensitivity.  Depth is debatable, I find they're all pretty close in my mild soils, I don't think the F-pulse is any deeper than the Carrot AT in my soil, they both seem similar.   In the wet sand the F-Pulse wins by a country mile.

Now that I know these issues with my TRX are normal they don't bother me, it's the thought that it was faulty that annoyed me, especially when its my second one and I paid a fortune to get both of them with the shipping from USA.   The manual of both the Pro-Find and TRX should have had a section explaining the EFE, if they did that they'd get a lot less complaints and warranty returns.  Minelab were happy to swap mine over with that being the fault, even though they said it was normal.  Waste of money that was for them, now they're stuck with a used Pro-Find that works to specification because they didn't explain the quirk in their manual.

I intend to leave my TRX in sensitivity 3 for general use and if I need to find a tiny nugget I'll quickly switch to sensitivity 4, easy enough to do.  Now I understand it and know it's not a lemon I'm quite excited about using it again.