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A different View

cachenut

New member
My view of how a detector works is that it samples a bucket of dirt under the coil to see if there is a signal consistent with a coin or other target and responds accordingly. It does not really look at individual targets but considers everything in the bucket at once. So if there is a pull tab, penny, and nail the reading you get is for all three combined. My explanation of detector behavior goes from here.

I also think a detector samples several buckets of soil and targets as it sweeps over the ground. So if some bucket or successive buckets have the coin signature in them the detector rings coin.

This is why close targets can make identifying a coin or other target difficult. It all adds up. While the detector may give a high coin tone it is difficult to find exactly where it is. Only by going over the exact spot do you get the best id you can. Otherwise other things get added in.

Close targets also make pinpointing difficult because of the same reason. The other targets contribute to the location until you are exactly on top of the target and it is difficult to get the Exp II to detune to the exact target strength you need to ignore everything else and pick the right target. As I said I have a good idea where the target is before I pinpoint especially when there are several targets.

I find that a coin can light up other targets around it, so to speak. Since some target on there own are not good enough to ring in the coin can get added into their score and ring in as a good target even though they are not. If I can remove the coin or other strong target they often disappear entirely. The advice when in doubt dig is good for high tones unless there is a good reason to ignore it.

I do think increasing sensitivity and gain raises the numbers. Primarily cause it adds in other things. I sometimes get a high tone cause a piece of tin foil is down there with some other target and they add up. Raising sensitivity and gain increases the physical area sampled (bigger bucket) used by the detector so it is more likely to include the extra targets.

Also there is iron in a lot of our soil so increasing the sensitivity or gain increases the amount of iron included in the sample and the size of the bucket. The iron numbers go up. And of course there may be a nail hiding out down there somewhere that gets included.

Anyone disagree or can add to this please respond.
 
I am not as knowledgable as some on the EX but, I feel sure that raising the sens and gain do not raise the digital numbers. There are two reasons, first gain only increases the volume of the signal and second as I understand signals are more apt to be averaged than added together. Just think about it. If signals where added you would never get A good signal. Just my thoughts.

AK in KY
 
I definitely don't know why I am chiming in on this...
but.. I will.. and someone can correct me.. again.. if
I'm way off...

Seems someone suggested to use the digital screen rather
than the smartfind to avoid some of the averaging that is
happening in smartfind.. and when I use the digital screen..
I sometimes see multiple icons.. I don't know how multiple
icons would be shown if the signals are averaged first?!
Maybe signals are averaged for sounds but not display?!

Is there a difference is the processing in smartfind as
opposed to digital?! and... do the signals go into the
processor as raw data.. i.e., does the gain only affect
the output to our hearing?! I have no clue.. only questions..

If someone is "hearing" a sound that sounds to them as different
than what is seen visually.. maybe that is an indication that
there is something more there than what is being heard..

I dunno.. if something is apparently working for someone...
and it doesn't "jive" with the theory.. which is correct?!
the heck if I know... just raises more questions for me..

clueless...
Dan
 
It samples the target individually. What makes this a little hard to see is the frequencies contained in the electromagnetic field, 3.5khz-100khz per second are so fast that a target appears to stand still in relationship to the mechanical sweep speed. Soil signals are discarded so only refined iron and other metal or conductive materials are analyzed. They are examined one at a time. In the unfortunate event that two are sensed at the exact same point in time then some method to select a dominant signal is used. However, the speed of operation essentially eliminates this, I think.

When we think of 3,500 to 100,000 pulses per second that are transmitted, sampled, and accepted or rejected we get some idea of how complex the EX2 is and why it can look at each signal. We are talking about nano seconds of operation of the electronics which is a little hard to see when we operate on minutes and seconds.

Hope this helps,

Cody
 
Just a comment about your analogy. If the Explorer coil were a concentric coil the bucket analogy would fit. But since it is a double D coil the idealistic area under the coil being analyzed by the detector is more like the blade end of a paddle, wide and flat as opposed to round and conical.

That's why when you get an iffy signal you should turn perpendicular to the target and sweep from a different directions. Also you can reduce your sweep to a few inches back and forth over your suspected target and not be looking at bucket full of area. This helps narrow down your pinpoint area and also help eliminate some of the trash that may be getting averaged into your reading.
 
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