Manticore - Extreme Bump Sensitivity

[Tesorodeoro]

So I know this detector has been out for a few years and there was a lot of posts and online activity in the past. I’m confused as to why the extreme bump sensitivity in Goldfield mode is not being discussed more. EVERY SINGLE time the coil brushes up against grass, small twigs, coil touches the ground, bumping small rocks, etc results in falsing and noises. Impossible to skim the coil along the top of the ground. This is with the M11 coil and sensitivity at 20. Is that too high in this mode? I’m expecting to detect 5-10 grain flakes of gold a couple inches deep. Are the factory settings all wrong or is this how this detector operates?! Am I being a cry baby having to learn a new detector? I’d compare it to a semi truck at night with a loose headlight bouncing around. Am I missing something here? People have said to buy an aftermarket lower shaft. I don’t see how this would have anything to do with bump falsing except maybe it’s stiffer? Appreciate any discussion that results.

 

[jmc24]

I'm beginning to think most lower end detectors with carbon fiber shafts are conductive enough to be detected by the coils used.

I don't think most lower end detectors with carbon fiber shafts are conductive enough to be detected by the coils used.

I know they are from experience and the price range is from low to high end. This mostly applies to higher frequency VLFs with hybrid all metal gold prospecting and /or specific low conductor programs running above 20 kHz. One detector that has a CF shaft which isn't conductive is the one on Deus 2. Its CF tight weave lower shaft is dead quiet even using the Goldfield program in Pitch 2.

Lots of PI detectors have carbon fiber lower shafts which their coils will not detect.

 

[Assembler]

I don't think most lower end detectors with carbon fiber shafts are conductive enough to be detected by the coils used.

I know they are from experience and the price range is from low to high end. This mostly applies to higher frequency VLFs with hybrid all metal gold prospecting and /or specific low conductor programs running above 20 kHz. One detector that has a CF shaft which isn't conductive is the one on Deus 2. Its CF tight weave lower shaft is dead quiet even using the Goldfield program in Pitch 2.

Lots of PI detectors have carbon fiber lower shafts which their coils will not detect.

Well, the best test is to take the carbon fiber shaft off and try testing with different coils.
I do agree that the detector needs to be running a frequency 20 kHz or higher to start responding to the carbon fiber shaft. You could be surprised at the results.

 

[jmc24]

Well, the best test is to take the carbon fiber shaft off and try testing with different coils.
I do agree that the detector needs to be running a frequency 20 kHz or higher to start responding to the carbon fiber shaft. You could be surprised at the results.

That is one way to test this.

Another more realistic way is to duplicate the scenario that Bill Southern experienced and rock the coil on the shaft and see if the back end of the coil starts to detect the shaft as the coil gets closer to it. That kind of coil to shaft motion which Minelab did not address in their email reply cited above, is a very common scenario in the gold fields when a detector prospector starts to recover a target that is already in their scoop. Many relic hunters use it too by just passing their hand which is full of dirt over the coil while it is laying flat on the ground. Any bumping or vibration of the coil that causes even slight movement between the flattened coil and lower shaft will create a series of target responses until that movement stops.

 

[Assembler]

That is one way to test this.

Another more realistic way is to duplicate the scenario that Bill Southern experienced and rock the coil on the shaft and see if the back end of the coil starts to detect the shaft as the coil gets closer to it. That kind of coil to shaft motion which Minelab did not address in their email reply cited above, is a very common scenario in the gold fields when a detector prospector starts to recover a target that is already in their scoop. Many relic hunters use it too by just passing their hand which is full of dirt over the coil while it is laying flat on the ground. Any bumping or vibration of the coil that causes even slight movement between the flattened coil and lower shaft will create a series of target responses until that movement stops.

Most manufactures will pin a molded plastic end piece for the mounting of the coil that is not conductive. Whereas the carbon shaft is the usual problem conductive part. If the coil is moved over the molded plastic end piece, there is less of an issue compared to touching the coil to the carbon shaft is the real issue.
Testing will give some answers of what the issues are if the shaft is conductive enough with the frequency used by the metal detector.

A much larger coil could be even a bigger problem of responding to the short carbon shaft. Testing will give some answers.

 

[Assembler]

Anyone try wooden sticks or dowels yet?............LOL.

A size chart of different coil manufacturers would also be helpful in fitting different coils to lesser conductive CF shafts.

 

[Assembler]

Thanks for that. The Goldfield program did seem like an afterthought if I remember correctly. It really does make a good relic mode.

I’ll have to check out other discussions.

Did you experience similiar bump issues with the stock detector with the 11” coil? Did you notice any improvements using the M8 with the custom lower rod?

Sounds like there are good reviews/results. I’ll check it out and post an update as to how it resolved this issue.

Any update information.
Thank you.

 

[Tesorodeoro]

Nope. unfortunately

 

[Assembler]

Nope. unfortunately

I'm thinking that any improvement or change of the factory lower shaft will help with the responding to the small 5 - 12 grain targets.

 

[Assembler]

I'm wondering if a more realistic depth is 1/2" - 1" with the 8" coil for mineralized ground?