X 70 sensitivity settings

[B.T]

Here's some stuff about the 70 and too high sens settings.
In disc mode if you run it too high when there are multiple targets present, say ten in just one sweep area, you will experience target overlap as the coil picks up those around its periphial as well as the one under it. If those either side or in front etc are of a lesser valuable kind like a big bit of iron next to a great coin or whatever it can give the call on the junk because of its larger overriding signal. Blanking your once in a lifetime find.
The closer together your targets then the lower you set your sensitivity. The further apart then you might set it higher if the minerals allow.
This, targets close together, also has an effect on your sweep speed.
Go as slow as you need to to analyse them all.
In prospecting you set the sens according to the minerals.
You will get to know by listening to your threshold.
When there are no rolling mineral sounds or slight threshold drops or rises you can crank it up to the point where the changes are just gentle rolls in the background hum. When they increas you will know its time to turn it down to the acceptable level you choose to hunt with. When they decrease turn it up again.
Work off of those threshold background rolls, drops and rises as they are your key to make changes.
Too fast a swep may cause these changes too so be carefull that its not your fault your hearing them instead of the actual minerals.
Use a little test bit to get your sweep speed right everytime before you get started.
Good hunting.

 

[Jackpine Savage]

Good post BT, I totally agree. I don't prospect but I do constantly ride the sensitivity setting when hunting extremely trashy or iron filled areas. I know some say to run in all metal in high trash areas for faster recvoery from target to target but there are times when I like to notch out the predominate iron tone for a little quieter ride. I then raise or lower the sensitivity based on the amount of nulling. Lowering the sensitivity reduces the nulls and allows for better see-through when in a high trash (many nulls per sweep) area.

Tom

 

[GoldinOhio]

Hi, BT.

I have a question about the X70 and sensitivity set too high in your post. I'm real new to metal detecting, still on my first set of batteries in my 70. But you said:

"In disc mode if you run it too high when there are multiple targets present, say ten in just one sweep area, you will experience target overlap as the coil picks up those around its periphial as well as the one under it. If those either side or in front etc are of a lesser valuable kind like a big bit of iron next to a great coin or whatever it can give the call on the junk because of its larger overriding signal. Blanking your once in a lifetime find.
The closer together your targets then the lower you set your sensitivity. The further apart then you might set it higher if the minerals allow."

My question is, if you set your sensitivity lower, might it not even see the coin next to the piece of iron? How do you know if you've set the sensitivity too low / too high other than chattering and instability? And how do you know if the instability isn't just due to alot of trash and targets in a very small area? Is this just one of those cases where you dig it anyway because you just don't know? (I think I might be answering my own questions because I don't think I have enough learning time logged. But I'd be very interested to hear what you have to say if you'd care to.)

Thanks!
-Pat

 

[bfodnes]

Now that the small 6" seems to come that will change it some too.....

 

[Jackpine Savage]

Hi Pat

As BT pointed out iron can easily mask the signal from good targets. Basically there are only a couple of ways to deal with it, either go to a smaller coil or lower the sensitivity.

if you set your sensitivity lower, might it not even see the coin next to the piece of iron

It might or it might not, no 2 situations of co-located ferrous/non-ferrous targets are the same but, in general, lowered sensitivity in heavy iron/trash is necessary with most detectors.

With the X70 and its non-linear sensitivity range consider settings above 19 as relatively trash free settings and for heavy iron/trash use 19 or below. With the stock concentric coil you have no choice but to reduce the sensitivity in iron/trash for the reasons BT pointed out. A small coil would help but, for now, reducing the sensitivity and overlapping your sweeps so that you "paint" the ground with the open center area of the coil will give very good results using the stock coil.

I hope this helps some and feel free to ask away if not.

Tom

 

[GoldinOhio]

Thanks, Tom for the reply.

I think I've been running the sensitivity too high for the trashy areas I've been digging. I'll cut it back and use the HF 5x10 DD coil until that new 6" comes out.

I was just afraid that using the HF coil with lower sens would result in fewer good targets, or atleast fewer deep good targets. (It did find me a clad quarter at 8", though). I'm guessing its a balancing act of sorts. Less sens = less trash = less frustration = better seperation. Am I getting it or am I confused?

Thanks again,
-Pat

 

[B.T]

Spot on Tom I couldnt have replied better myself. Gotta keep checking and changing to suit all the time.
It often makes the difference between a good day and bady.
Have a good one.

 

[Jackpine Savage]

Pat, my reply was based mostly on hunting in iron. I'm really not the right guy to ask about hunting in modern trash. But yes, it is a balancing act and also just spending the time to learn what the machine is saying.

High settings do create a widescan effect as BT pointed out which greatly adds to masking. Also, a little caution with the elliptical DD coil is in order. Although it does see less ground it also has much greater sensitivity to tiny trash and foil. Some very experienced guys like it and report good results on coins with it but, it is not my favorite unless after jewelry at athe beach or sports field.

Tom

 

[Jackpine Savage]

Thanks BT! Just one point I did not make in my post and its more of a personal preference thing. When I run in all metal and hear all the tones it will cause me to slow down my sweeps but it does not alwyas "suggest to me" that I need to lower the sensitivity as well.. Now when I hear all the nulling from the notched out iron that does alert me to the fact that I need to lower the sens as well. Odd but thats how my brain works.

Tom

 

[Digger]

Coin hunting techniques are different than prospecting techniques. And, depending on the sites you hunt, conductivity levels of the trash you contend with will vary as well. I hunt for old coins at old sites. Very little modern trash. But sometimes there is a ton of old iron. Just as we all have different hunting styles, all of our brains work a bit differently too. My style is to hunt in all metal and run the sensitivity as high as I can, unless it is so contaminated with iron that the noise from "low range" targets is nearly continuous. Then I will switch over the a modified Pattern with ferrous rejection. However, I seldom lower the sensitivity more than a couple points. I recognize that lowering the sensitivity makes the trash less predominate. But in all metal mode, my detector won't make a distinction between targets I don't want to dig and targets I want to dig. Other than the tone's pitch. My point is, lowering the sensitivity setting will not only make the detector less responsive to trash. It will also make it less responsive to the good stuff too. This could result in totally missing that once in a lifetime find you referred to, due to lack of sensitivity as opposed to blanking it because of too much sensitivity. As overpowering as the audio tones may seem, I would rather hear them all and let my ears and brain make the decision as to what I want to dig. Lowering the sensitivity may work well for you. But coin hunting with a concentric coil, raising the coil and slowing down my sweep speed over a "congested areas" provides a similar solution in the sites I hunt. It just don't require changing settings. By keeping the sensitivity high, and making these two physical adjustments, I don't believe I am as apt to miss that deep old coin because I didn't want to contend with the audio response generated by an abundance of trash. JMHO HH Randy

 

[OldeTymer]

Hey Randy,

Wouldn't raising the coil be similar to reducing the sensitivity to some degree? If that once in a lifetime target were just at the edge of detection, with the coil on the ground, could it possibly be lost if you raised the coil to separate the signals? Of course, lowering the sensitivity to reduce the target "noise" could also lose that same target. I can see the validity of both points. The lowering of the sensitivity allows you to see between the targets much like raising the coil does. The old "high beams in the fog" analogy.

Just some out loud thinking.

I'd rather be out hunting,
OldeTymer

 

[Digger]

Each process will provide similar results. One is changing the electrical characteristics of the detector and one is a matter of changing the motion of your arm. I simply prefer to utilize the physical motion of raising the concentric coil and slowing down my sweep speed as opposed to continually raising and lowering the sensitivity settings. Then I don't have to worry about where I left the sensitivity setting once I get past that trashy area. That is what works best for me in the sites that I coin hunt. Different strokes for different styles of hunting! HH Randy

 

[OldeTymer]

[quote Digger] ---snip--- Then I don't have to worry about where I left the sensitivity setting once I get past that trashy area. ---snip--- HH Randy[/quote]

That is a very good point. Especially since I can't hardly remember five minutes ago anymore.

What was I saying????

Good hunting,
OldeTymer

 

[Jackpine Savage]

A couple points. If you don't want to miss the deeps ones (and who does) raising the coil seems counterproductive to my thinking. Sure, if you overlap to an extreme degree it may work OK but still gonna lose a lot of sensitivity to small/deep coins.

Since detectors always transmit the same energy regardless of sensitivity setting, what is the best way to reduce bad (iron) signals and retain the ability to see between the iron/trash for the good stuff. Is it lowering the sensitivity (use low beams in fog) or does that just reduce all signals being received proportionally with no benefit in seperation if the iron signal still predominates over that old silver coin. I know that if I can hear excessive almost constant nulling from the iron segment that I have notched out I can quickly and easily reduce the sensitivity one number at a time to the point where the nulling is reduced enough to allow non-ferrous signals to break thru.
In the end I do not know, techinically speaking, which method is best for dealing with iron. all-metal vs reduced nulling. Kinda sounds like the same "argument" that pops up on the Explorer forum frequently.

Raising the coil a bit reduces the ground response so I have read. Do these new detectors need that ground signal for proper operation ie: targets ID and iron handling??

Whatever method, raising the coil or reducing sensitivity, overlap, I repeat.. overlap your sweeps. Did I mention that in my post down below?

Tom

 

[Digger]

Tom, I agree with the overlapping sweeps. I did not say that raising the coil was good for finding the deep ones. I said, in my opinion, raising the coil will result in the same result as lowering the sensitivity. Both methods may cause you to miss the deep ones. My point in raising my coil is that I believe it accomplishes the same thing as lowering the sensitivity. I believe it makes all targets less noticeable. But, the primary difference is that I can raise my coil at the exact spot where I get an over abundance of signal. And once I pass that exact spot, lower it back down to the ground. This can be done in a split second and timing is determined by the sound that you control. (via sweep speed, sweep direction and coil height) For me, lowering and raising the sensitivity setting would not allow me to do so "target specifically", would take much longer to accomplish and would not give an indication as to when it was OK to raise it back up. Just my opinion and the preference I have for coin shooting here in the Midwest. HH Randy

 

[Jackpine Savage]

Randy,

I understand better now and it makes sense to use your method in the conditions you described.

HH

Tom

 

[B.T]

G,day Tom. Nothing odd at all. We all have differing techniques.
One of my friends detects so carefully that I know when I come back from an hour scout about he will be no further than 10 meters from where I left him. Another hates using threshold whereas I hate working without it. Its a bit like fishermen, one swears by one lure and another by something else. Main thing is we love what we do and even though some of our ways may vary we all end up with the desired results. Its amazing when you think about it just how "elastic" the abilities of certain detectors can be when they can be used in so many different ways and still get A1 results!
Have a good one.