Impact ground balance?

[Ptrevino97]

When ground balancing does the higher the number you get balancing mean milder soil and a lower number means more mineralized? Or vice versa?

 

[Monte]

more intense or mineralized the ground is likely to be.

Also glance at the MMI read-out on the lower right-hand side on the display next to the battery level indicator. It's best to view this display while searching a target-free area and sweep the search coil over the ground, or do what I do and after Ground Balancing the Impact over clean ground note what the MMI read-out is when slowly bobbing the coil.

Several older-use sites I enjoy searching close to me are gold mining era ghost towns and, for example, the GB read-out varies from '79.[size=small]20[/size]' to '85.[size=small]60[/size]' hinting that it is a more mineralized environment. Therefore, using the better GB adjustment approach for this type of varied ground, I usually adjust the GB to be slightly positive with a GB setting of '86.'

Also, keep in mind that when hunting ground that tends to be more mineralized, with both a higher [size=small](larger)[/size] numeric read-out and a more intense MMI read-out you will generally have better target response and gain the best possible depth-of-detection by using a slower and methodical sweep speed. A too-fast sweep can often have a negative impact by forcing in too much challenging bad ground signal for the detector to process well and pass along a target signal.

Rest assured, however, that you are using one of the absolute best all-purpose detectors on the market with the Nokta Impact in-hand.

Monte

 

[Ptrevino97]

Thanks for the info.

 

[Sven]

WE have a beach here that GB's 85.[size=small]80[/size] If you GB in any Di modes it will not pick up a silver water at 3" deep. Switching to other modes, the Impact will pick it up. The beach has black sand mixed in. Will say other dtectors I have tested don't fair any better in disc modes.

 

[General Custer]

In the highly mineralised ground of the GT I usually get a GB reading of about 65 to 70 on average.Higher readings are 75 to 80.With the discrimination option in GEN mode you get a low and high tone,instead of just one overall tone. the low tone picks up hot rocks and iron in high resolution sound.Normal speed sweep will identify a target and it is only when you sweep over it slowly will you get the iron low tone.

 

[Dave_E]

Monte,
I thought the numeric value referenced the type of mineralization in the ground, and the number of bars on the "Mineral" graphic showed the mineralization intensity?

Does the higher numeric value indicate a higher mineral content? How does that work with the number of bars on the graphic in the bottom right?

 

[General Custer]

The general rule is the higher the mineralisation content of the soil is the higher the ground balance value.The manual gives very little information on this.However I would have thought the GB value readout would vary in different search modes depending on the default iSAT and discrimination settings.But this is conjecture on my part.

 

[Dave_E]

Can anyone elaborate on the ground balance info displayed by the Impact along the lines of the OP's question?

Do the numbers displayed represent the type of mineralization in the ground, or the amount of mineralization?

What about the mineral graph in the bottom right corner with 5 bars? It's listed in the manual as a magnetic mineralization indicator.

Can the magnetic mineralization indicator be used to help discern deep iron when a high tone is hit?

 

[Monte]

Monte,
I thought the numeric value referenced the type of mineralization in the ground, and the number of bars on the "Mineral" graphic showed the mineralization intensity?

The numeric read-our does suggest the type or category of mineralization as noted on Page 9 of the Impact User Manual:

Ground Balance Value
Ground balance value provides information about the ground you are searching on. Some typical ground types are as follows:

0-25 Wet salt water or wet alkali soils
25-50 Wet salt water and wet alkali soils covered with dry layers
50-70 Regular, low-quality soils
70-90 Highly magnetic soils, magnetite or maghemite and similar highly mineralized soils, black sand

Does the higher numeric value indicate a higher mineral content?

Generally, yes as described in the cut-and-paste above. Also note the comment on Page 10 shown below:

(2) If the ground mineralization is too low, automatic ground balance may fail to work in other modes except for the COG mode. In such a case, you can auto ground balance in the COG mode and then switch to other modes or try manual ground balancing.

This is especially true in saltwater or wet salty environments such as alkaline ground that is wet or even layered. As the ground mineralization level increases, it will require a higher numeric adjustment / read-out in order to compensate for the negative ground environment.

How does that work with the number of bars on the graphic in the bottom right?

That graph, the MMI for Magnetic Mineralization Indicator, is explained on Pages 26 & 27 in the impact User Manual. it reads as such:

MAGNETIC MINERALIZATION INDICATOR
The Magnetic Mineralization Indicator consists of 5 levels. The indicator is shown empty at low mineral levels during search and at start up. In areas where the magnetic mineral level is high, the indicator level increases according to the intensity.

This measurement can be summarized as the level of magnetic property and intensity of the ground. Simply, if you are working in an area which contains intense and magnetized minerals, the level will be high. If you are working on a less intense ground, the level will be low.

Do the numbers displayed represent the type of mineralization in the ground, or the amount of mineralization?

As stated above, the manual says:

Some typical ground types are as follows: and then describes some general categories to consider.

The MMI read-out gives a bit of information about the the level of magnetic property and intensity of the ground and you can basically substitute the word 'amount' for the word 'intensity' in that statement.

Can the magnetic mineralization indicator be used to help discern deep iron when a high tone is hit?

No, not really. Besides, 'iron' can come in various sizes and shapes and configurations and, because of that, it will also pre4sent some varied conductive properties and there will be times that we can all be mystified by iron now and then.

I have found my Impact to provide better-than-average audio and visual performance to help me 'classify' most common iron that tries to fool us, especially when using the 7" Concentric coil.

I tried to keep this reply simple but point out the differences. It's all a matter of learning the detector and how to read or analyze the various ground environments we deal with, but I wouldn't be too concerned about it. Just GB the Impact, if anything tweak it just very slightly positive, use the best coil for the site at hand and enjoy the hunt. That's what I like to do. Just keep things 'simple' and have 'fun' and the Impact will provide great experiences afield for us.

Monte

 

[Dave_E]

Thanks for all that info Monte.

You explained it very well.

 

[Ptrevino97]

What effect would a slightly positive ground balance have, as Monte suggests.

 

[Monte]

What effect would a slightly positive ground balance have, as Monte suggests.

Every detector circuitry design can be a little different, especially in how they are initially conceived and put together by the design engineer. For example, with virtually any Tesoro model, the ONLY time I might adjust for a slightly positive GB is if I am deliberately searching in the Threshold-based All Metal mode. However, the reverse is true with almost all Tesoro circuitry designs where it is best to adjust for a slightly negative GB in All Metal because most of their models already have a too-positive off-set between the All Metal mode GB setting and the Discriminate mode GB reference.

With many Tesoro models, a slightly positive GB setting in All Metal can result in a loss of depth and even a loss of target response from very high-conductive coins and such. But with many other detectors of older design that also use a primarily analog circuitry, they might be best adjusted for a spot-on to slightly positive GB setting to get best in-the-field performance.

The Nokta and Makro detector designs tend to provide very good performance even if the GB setting is slightly positive from an Automated GB adjustment. Refer to Page 9, I believe, in the Impact User Manual and you will read the following:

"IMPORTANT! Experienced detectorists adjust the ground balance setting to a slightly positive response (weak but audible sound is produced when moving the search coil closer to ground). This method may produce favorable results for experienced users in certain fields where small targets are searched for."

This is the same recommendation Nokta makes in their other User Manuals for the CoRe and Relic and I have found it to be helpful for enhancing some of the deeper and weaker target responses. Also, because I hunt in mostly very mineralized environments, by adjusting for a very slightly positive GB seems to help avoid some of the 'noise' I might get from encountering rocks or pockets of bad ground that have even more iron mineralization than the adjacent areas when I might GB 'spot-on.'

With ample detecting time and working a wide range of ground environments, an avid detectorist will get a better 'feel' for the settings that might enhance their field performance and tweaking a slightly off-set GB with different detectors has generally worked in my favor for decades. The Nokta suggestion is a good example that the manufacturer inserts in the User Manual to help newcomers learn what they might want to consider that can be to their benefit.

It's always best with these devices to NOT use a negative Ground Balance and adjust them to be close to 'spot-on,' but there are benefits we can get my manually tweaking the setting very slightly more positive. Time and practice will let us know if it helps us in our ground environment or not.

Monte