Intro to Preset Coins Program Page 42

[Cody]

P32- Introduces discrimination and the preset Coins Program. This program is a COMPOSITE of hundreds of coins from around the world according to Minelab. We need to keep this in mind that is the pattern is FOR NON-FERROUS COINS OR targets that match the conductivity/SIZE and FERROUS CONTENT of a target. Where are FERROUS COINS? They are found over in the black area at far left side of the screen from about half way up from the bottom to the top left of what is IM-15 right where most nails hit. Unfortunately the upper left is where some Indian Head pennies hit. WE CAN MODIFY this pattern if we want to but this is an excellent pattern when searching for US coins and jewelry.

What we may not realize is if we like icons we are only going to see the default ICONS FOR COINS and JEWLERY. If we want other icons we must select them in the menu. The program I use is designed to display ALL ICONS but trash and good ones all the time. If you have not read my post on how to do that I will post it again.

Stored in a lookup table are the TCs for non-ferrous coins. Notice that we have been told the area that is now indicated as non-ferrous is actually ferrous content. We kind of agree that the left half of the screen is ferrous and the right half is non-ferrous but actually the entire screen in on the horizontal axis is ferrous content and then it really represents ferrous content. If the coil is passed over a target then that target data is compared to the data stored in the lookup table for those that are

 

[Cody]

The preset coins program uses null and tone discrimination so it helps to understand a few things out null discrimination. The concept of null discrimination is a rejected target, anything in the black area, will cause the threshold to go silent to alert the operator to a rejected target.

Hear are the problem with null discrimination. We cannot detect a target while the threshold is in null and the coil is in motion. That may sound strange to some of the old pros so do this to see what I mean. Take a piece of iron and hold it still so the threshold nulls, it may be easy to hold it in back of the coil, then sweep a coin past the coil with the other hand. Although the threshold was in null the coin is detected with no problem. This may cause some folks to think we can detect a good target while in null but we cannot.

The problem with what we just demonstrated, if you tried it, is the iron is motionless and the coin is in motion. Now hold the iron and coin in the same hand and sweep them past the coil and the threshold will go null. This kind of helps us to see how motion is needed for this detector to work properly other than in pinpoint.

WE CANNOT DETECT A GOOD TARGET IS THE THRESHOLD IS IN NULL.

To detect a target after the audio or threshold goes null it must recover. This is why we have FAST as a function to force the threshold and audio to return to the point of being ready to go positive quicker. A minor problem with FAST is that we don

 

[Cody]

Iron Mask is in my opinion and unfortunate name for this function. If you notice one major national distributor would have us believe that iron is no longer a problem as we can detect good target and completely ignore the iron. I have virtually no respect for that particular distributor but that is another story.

Iron Mask is discrimination for the left side of the screen. Instead of going from Right to left starting with 0 at the right and 31 it starts at about half wave across the screen with 0, then -1, -2 and on to -15. Notice that if we count 0 then 15 negative numbers we have a total of 16 digits so IM-16 is just a way of saying ALL METAL.

Iron Mask allow us to select any of the negative numbers to represent a ferrous zone. In each zone there is from the bottom of the screen to the top 31 conductive levels. Iron Mask is a discrimination screen if we use and of the zones from 0 to -15 but we have to select all 31 levels of conductivity for a zone. We also cannot select a higher zone unless the zones lower are also selected. So, if we select IM-12 then we have also selected IM-13, IM-14 and IM-15 and all 31 conductive levels in each IM setting. Also, Iron Mask cannot be saved in a memory location. What is better in my opinion is to create an iron mask in the Smartfind screen and save that if we want to do so.

With the modified Preset Coins program I use IM-16 which is ALL METAL and if I am having problem then will push the pad for Iron Mask. There are times when a target is on will hit in the clear are with one direction of the sweep but in the black area with another direction of the sweep. I guess this is what is meant by unmasking as when we go to all metal or an IM level that opens up the target to all direction of the sweep we get a much better idea of what the target is.

Someone posted that neat way to make our last adjustment in advanced then go back to Quckstart so we can switch back and fort between screen and not go through the Learn and Edit screens. Anyhow this use of Iron Mask and the modified Preset Coins program really works nice.

Have a great day,

 

[Cody]

All ICONS are not turned on in the Preset Coins program. It does not make any difference if the right side of the display is clear we only have the Coins ICONS turned on.

Go to Menu and Select all ICONS except for Nails and Screw caps if you are using the modified Preset.

If using the Present Coins as is then select all ICONS except for Nails.


Even if the area where a pull tab hits is clear we do not get an ICON for a pull tab unless we select the ICONS. If you have accomplished the above you now notice that when a target is detected we have ICONS to help with the ID other than just Coins and I think Rings.
I will post a program later that demonstrates how to use Conductive tones and the icons to tell a nail from a silver coin using ICONS.

This modified Preset Coins program is one from my book on metal detectors that will be published in the next year. I am not attempting to sell the book so don't worry about that. I don't need the money and am mostly doing the book for my own interest and as a long term project I have been working on for many years.