why does the detector say its a coiin?

[jameskaufmann]

why does the detector say it's a coiin?

when the screen and sound says coin, does the detector id the target by metal content or round shape? washer,bottle cap, ect. or both. i can't seem to find the answer. thank's.

 

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[Mortamus]

depends on which detector your using...mine does both shape and what the metals are made of..
A diamond ring will come up the same as a pull tab..why? because the alloys are close and the shapes are close ...even more so on the old big round pull tabs...but..if your not digging those pull-tab signals your not going to find jewelry son..
What kind of machine are you using?

 

[christo000]

Agreed more higher end the machine more info u get

 

[Terry Soloman]

The real answer is the frequency of the return signal. When your VLF detector transmitter coil transmits at say 7.5kHz - or 7,500 sine (radio) waves per second, a magnetic field sets up around the metal object, and a particular frequency signal is transmitted back to the receiving coil depending on the density / alloy type of the metal it is seeing. The circuitry is programmed to make its best guess at what that metal is ferrous, or non-ferrous. Silver, brass, and copper for instance, are easier to separate from iron, lead and aluminum, while nickel and gold are not.

FAQ's about metal detectors - Q: How does discrimination work? A better word for discriminator is perhaps "differentiator." At minimum or no discrimination, all metal within the detectable range is detected. As you slowly increase discrimination, small pieces of metallic trash and ground mineralization are ignored (rejected). As you increase the discrimination, pull tabs, small nails, foil, and even some good targets (such as gold rings and nickels) will be rejected. The best way to learn the discrimination points (the lowest discrimination setting at which an object is rejected) of your detector is to scatter some sample targets, such as coins, pull tabs, and foil on the ground from 1-2 feet apart. Starting at 0, or your detector's lowest discrimination point, scan each target. Gradually increase discrimination and record the results. With practice, you should be able to determine whether or not to dig by listening closely to the target signals.

White's Metal Detectors - Metal Detector FAQ's What is discrimination? Discrimination is the ability of a metal detector to tell the difference between different types or alloys of metals. This allows you to selectively dig up only those types of metals likely to be of interest to them. There are audio (speaker/headphone) types of discriminators and visual (meter, LCD) types. Most higher end models have both types. The idea is to increase the odds in favor of digging valuables, and decrease the odds of digging trash.
5. Can a detector be set only to respond to gold? [Top of page]
No. There are too many variables with exact alloys and sizes to pin it down tightly enough to dig only one type of metal. For example, a large piece of gold may read high on a display or audio discrimination scale and a small piece of gold may read low on that same scale. Gold with some copper, silver, or platinum within its natural alloy will indicate differently. And other metals with similar electrical characteristics may read identically. Lead and aluminum are the most difficult common trash metals to eliminate. Even with the most sophisticated detectors available, expect to dig some trash. But a good discriminator increases the odds in your favor.

 

[Tom_in_CA]

reply

when the screen and sound says coin, does the detector id the target by metal content or round shape? washer,bottle cap, ect. or both. i can't seem to find the answer. thank's.

No, it does not go by shape. It goes by conductivity. Different metals have different conductivities. Some are close to each other (gold and aluminum), some are far different (silver and iron), etc...

And unfortunately, size plays into it too. So for example: a finger-nail sized snippet of an aluminum can (or the tab or beaver tail portion or whatever), might read in the nickel to tab range, right? However, an entire aluminum can will read up at penny or quarter or whatever, right? And in each case, the composition never changed. It's still aluminu. Only the size of the item changed.

 

[jmoller99]

Sometimes there is more than 1 coin in the hole, a coin and some trash, or a bunch of things, that together give you a conductivity reading that looks to be in the range of a coin, or something else entirely. I often would follow behind other detectorists, who skipped targets because their on-board meter VDI display told them that the target was not something it recognized as a 'good-known' target - I usually dig these. I often came up with a great target right next to a trash target (one time it was a small badly deterorated leather pouch with 2 keys and 8 coins, 2 of the coins were silver) - see what your detector reads when it passes over a target like that - it may give you a reason to dig something that your detector thinks is trash. VDI's are tools to help you, but they are only guessing what the target is based on conductivity.

When you are hunting with your detector, it's really not a good idea to assume that each target has no other conductive material nearby. Any parks I have ever been too tend to have a lot of conductive trash near the good targets.

One of the things that is great about the Tesoro Campadre is that it is sensitive to small gold chains (something that reads as trash to many detectors) - it has a single knob and a head phone jack. Its the cheapest Tesoro out there, but, once you get used to it, it's quite effective at finding things. Its simple and forces you to pay attention to what it is telling you.

If you have a detector that can give you a VDI reading, it is only one of the things there to try to help you - sound is another. Because of the extra stuff in the soil - VDI's can guess wrong more often than not.

 

[dirtfisher23]

Good replies

 

[jmoller99]

Keep in mind that there is discussion going on about changing the composition of US Coins (like they did with the Penny, the Government wants to be able to make them cheaper), so if that happens, any new coins with changed composition will likely read very different than they do now (which would mean that any detector that tries to guess the coin types would have yet another set of variations to deal with).

I have also found coins from other countries (without ever metal detecting outside the USA) - they also often read somewhere between other coin types. So, what your detector thinks is a coin is all relative.

I detect for Relics far more than coins - Since I have no idea what I will find, any guesses the Detector makes will probably be wrong most of the time anyway. Nothing wrong with that. A huge piece of iron (as I have found more than once) buried under a few feet of dirt can really throw you off. I have found crushed/buried 55 gallon drums, tin cans, aluminum cans, engine parts and old plumbing fixtures when looking at abandoned homesites.