Still learning and confused

Sounds like you're using a large or standard coil which will bring the nail/dime in the same detection field on a N/S sweep. Do you have a small coil? Some will recommend a particular brand of detector to better handle this, but it's still a TOUGH situation. Personally, a small coil is my favorite backup.

Thanks for the info Slling! Yes, I'm using a 12" coil. Was looking at the 8" this morning on the web. Not sure I want to throw more money into this at this point. But understanding the issue really helps!

Your Vanquish 540 is a great entry level detector that has features on it that many older intermediate level detectors simply do not have. However, one thing that slightly handicaps the 540, 440 and 340 is its just barely average target separation ability especially in detecting areas with lots of man-made rusting iron targets. Why does a new XP Deus cost $1200 to $1500? You have to pay for outstanding, best in class target separation and super fast recovery speed technology along with all of the other features on the Deus.

"Iron" targets are not just iron. They are usually alloyed with other metals. Rust is decomposing iron which can respond differently from non-rusted iron. Target orientation, bends in the iron, screw threads, misshapen and broken iron objects will all sound differently on some simultaneous multi frequency detectors like the Vanquish models. The processing of the simultaneous different frequencies on the Vanquish are setup to really concentrate on non-ferrous responses. They will try to identify even iron targets as non-ferrous. The target IDs for ferrous objects and their tones can be anywhere on the scale or one iron target can have multiple ID numbers and differing tones especially if you have the Iron Bias set on low and you are accepting the entire target ID range on the 540 by pressing the horseshoe button. With the Iron Bias setting on low, the Vanquish 540 will apply a filter which will more accurately identify shallower iron targets that are quarter to half dollar sized and smaller. Set on high, it will give the 540 and even better chance of identifying even medium depth iron objects which aren't too big. Having it on high may also start to identify adjacent non-ferrous targets as iron however depending on their size and orientation. So again, detecting in iron infested areas is always a trade-off.

Try your above experiment with both low and high Iron Bias settings and with differing amounts of iron discrimination.

If I am using a Vanquish model and I hear iron tones and non-ferrous tones-especially really high ones, over what seems to be a small target, I will carefully investigate that target. I will pay close attention to the depth meter and to how many directions in that 360 degree circle give me a good repeatable high tone or iron grunt. I may change the Iron Bias setting too.

Here are a few things you can try. If your 540 came with the 8" coil, use it. Also, use the mode with the fastest and best target separation/recovery speed which according to the 540 manual is Coin mode. The responses from targets will be shorter and you will lose some depth but there is always a trade off especially when dealing with iron targets. Relic mode is the deepest but has the slowest target recovery speed and the worst target separation. If your 540 is fully updated, use the new iron audio volume adjust feature that lets you have ten increments of iron volume and set it the way you like it. Experiment with Iron Bias high and low settings. Read the online manual.

CallMeGrey said:

Thanks for the info Slling! Yes, I'm using a 12" coil. Was looking at the 8" this morning on the web. Not sure I want to throw more money into this at this point. But understanding the issue really helps!

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If you only have the 12" coil you will have to really work on your coil control. With the Vanquish 12" coil you can investigate "iffy" iron/not iron targets with tiny, very level, 3" or so swings right over the target that just uses the center spine of the coil. Those swings in a 360 degree circle can tell you a lot.

Thanks jmaclen! That's the kind of detailed information I was looking for. That really helps me understand how my detector works. Now to work more on mastering this skill.

CallMeGrey said:

I've gotten permission to MD a yard with a house built in the mid 1800's. I've been running into old rusty nails and bolts and the issues that come them. When I pass over an old nail in the ground I get readings all over the scale. So I tried a test this morning with my Vanquish 540. I put an old rusty nail next to a dime about 2" apart. With the nail pointing north/south and me swinging east/west, the detector easily picked up the dime without the usual high tone clatter from the nail. But when I swung N/S it didn't pick up the dime at all (and again no 'clatter').

So my questions:
1.) Does all the false readings from a nail in the ground come from the surrounding mineralization from the nail? I thought it was caused by the detector hitting the 'edge' of the range when passing over a nail.

2.) I understood that the best way to confirm a solid coin signal was whether it was repeatable swinging 360 degrees around the target. But it doesn't register when I swing parallel to the nail. So I would be losing the signal half the time.


I need to get better at this stuff! The yard has turned up an early 1800's button and I'd really like to find some old coins there. But dealing with the rusty nails and bolts has been difficult for me so far. I know this is going to be a great learning experience though. Any suggestions?

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In a perfect world, there would only be one target under the coil at a time, and the 360 degree swinging would work. Unfortunately, we do not live in a perfect world, as many times there are multiple targets in close proximity to each other. A smaller coil will definitely help, as it "sees" less dirt, and therefore fewer targets at a time. A nail parallel to a coin presents problems to all detectors. Period. When you swing over the parallel nail next to a coin, the detector "sees" the length of the nail. If the coin is close enough, it will be "masked" by the nail. With the nail in the other orientation, the distance from the coin again comes into play. If the coin and nail are simultaneously detected, you could get either the iron signal (likely), the coin signal (rarely), or "tone blending" of the two signals. The recovery speed of your machine also comes into play in this scenario. Suppose that while you are swinging over the coin, your detector is producing a tone alerting you to the nail... you won't hear the coin! That's one example of a "one way" signal. Example: Low tone on swing, high tone on the return swing... VDI will likely be all over the place as well. Could be a good find or could be junk. The only way to know is to dig it up. Try varying your swing speed until you find a speed that works for both you and your detector. And on questionable targets, narrow your swing down to 3 or 4 inches, while working your way around the target to get more info. On some machines, reducing the sensitivity can help as well. Finally, you are doing the right thing by experimenting with your detector. A lot can be learned with a piece of plywood on a "clean" spot of ground. Try various arrangements of coins and nails, bottlecaps, bits of wire, pull tabs, ect. Swing over them from different directions, listen, and learn the language of your detector. Don't forget to try a gold ring as well. Want a real eye opener??? Try a jar full of coins and see what that sounds like! Hope this helps. GL and HH!

Welcome to iron masking with a parallel nail