5, 14 and 20 kHz Applications
To really understand what the Anfibio Multi offers it’s a good idea to perform a simple demo of each frequency setting. Get some targets of different conductivities–for example a silver coin, some small gold or aluminum. Switch the machine to Gen mode. Begin in 14 kHz and note how the detector responds pretty much the same to each kind of target. Then go over to Options and change to 5 kHz. Test each signal again. Notice how now, when you raise the coil away from each target, the gold does not respond as well, whereas the silver signal is stronger. Now press Options again and go to 20 kHz. Now the opposite will be true–with the silver sounding off more weakly and the gold coming in stronger. In each Frequency–targets in the corresponding conductive range will be a better, cleaner signal that’s available with the coil further away. It’s a good idea to become familiar with just how pronounced these differences are in that each frequency also has negative effects: 5 kHz is more stable in bad ground but is sluggish and does not separate as well in iron as do the others. Its meter responses are more defined though and therefore 5 kHz makes a good cap checker–“taming” these diversely alloyed targets for easier identification. 14 kHz is more of an “all purpose” frequency–responding well to all metals. 20 kHz is more nimble in iron–faster, with better separation. 20 kHz sorts non-ferrous objects from iron with precision. I’ve had good results with this setting–pulling steel clad Canadian coins out of black sand. These were deeply buried and had been missed by other machines for so long that they came out purple! At the same time this high frequency is less stable and tends to be noisy around salt sand. Because of this light, fast, nimble operation, 20 kHz makes a good “trainer.” If you can use the Anfibio’s other features to stabilize the machine and identify targets in (the more scattered ID’ing) 20 kHz–the slower frequencies should be easier to manage.
The idea is to know when the benefits of running a particular frequency setting outweigh the drawbacks–or to take measures to offset these. So as a general guide:
5 kHz: stable, deep on high conductors but sluggish in iron or multiple targets
Remedies: -using 3 Tone (Gain less than 90) to get a faster response.
14 kHz: good all-around performer but can lack stability or small object sensitivity around black sand or in bad ground.
Remedies: -high Gain to bring up small targets or conversely, lowered Gain (or higher bottom Discriminate / Tone Break for more stable operation.
20 kHz: good low conductor sensitivity, good separation / in-iron performance but noisy / less stable / scattered meter.
Remedies: -3 Tone operation or lowered Gain for stability. Other choices include higher bottom Discriminate / Tone Break for more stable operation and to reduce the responses from foils, steel and iron. Smooth, even coil passes and use the cross sweep to get stable ID on targets. Lowering the ID Depth feature is also a good way to offset the sensitivity of 20 kHz mode–to allow more defined reporting.
Another simple cross-checking strategy is to have the frequency selector as your “last feature changed” on the “Options” menu. Then with one press–you are ready to check targets in another frequency.
These represent good examples of the kind of mindset that will help you to get top performance from a high fidelity detector like the Anfibio. There are very few conditions-related problems that it’s not possible to find a solution to if you have a solid understanding of what the various features and settings do and how these relate to basic detector theory. At the same time, when you want to make a change to accomplish a particular task–there may be other aspects of the performance that are affected. These may need to be addressed as well.
From: Successful Treasure Hunting with the Nokta / Makro Anfibio Multi
by Clive James Clynick (2020)
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