How much is too much?

[Buried Crap NJ]

Remembering that I come from the GT/Excal to the 3030, and am mostly a beach hunter.I have learned that too much sensitivity is bad in BBS. It tends to bounce off the surface and not penetrate the ground. I read all the post and have to try and use some of the techniques for myself. I have tried some dirt hunting and see the machine works so differently than at the beach.So my question is when the 3030 is recomending 12 as a setting for the sens.how much can it be pushed before or if I am going to far.Minelab says Not to use the auto on the beach as it can't keep up to the frequant changes of the minerals.My first 20 hrs I was running as high as I could without falsing. As I learned to use the machine features I became more confused at which is better, higher or recomended?
BCNJ

 

[Digger]

Sensitivity is the detector's level of response to targets and their environment. Increasing the sensitivity may provide a more solid response on targets, but it will also increase the "false" signals from that "environment" and on smaller ferrous targets. Your detector is also more succeptible to electrical interference with a high Sensitivity setting. Decreasing the Senstivity will likely cause your detector to operate "smoother" and provide better discrimination / TID. But having it too low it can also reduce your depth of detection. So in regard to your question as to "how much is too much"...... as much as your "detecting skills" can handle. If you feel you need to have more depth of detection, you'll likely turn it up. If you get tired of repreatedly rescanning the "beeps" to see if it was the solid hit of a target or another false signal, you'll likely back it down some. I know the manual says to not use Auto on the beach. But on the beaches I hunted during test procedures, I found Auto+2 was very stable and effective. I just made an effort to sweep a bit more slowly to allow the detector to better analyze (and adjust to changes in) the sand. JMHO HH Randy

 

[Jason in TN]

Don't care what minelab says don't be scared to try auto at the beach I have ran mine at auto+3 at the beach a bunch and it ran great. Don't understand the it can't keep up thing in auto at least it is changing manual it don't change at all unless you change it. Seems that is pretty slow to me. Mine would run as low as 13 and saw 31 one time did not even know it would go to 31.

Jason

 

[Erik in NJ]

I recall a post from Minelab once that said that sensitivity does not affect depth of detection at all. The machine is always sending the same signal into the ground regardless of sensitivity setting. I believe what it affects is the DSP algorith in the machine that affects the accuracy of the TID (both visually and aurally). The post was interesting as several questions were posed to a Minelab engineer and answered in an email. It may have been Jason in
TN who asked--I don't recall.

 

[Digger]

Sensitivity controls the detector

 

[Buried Crap NJ]

I recall a post from Minelab once that said that sensitivity does not affect depth of detection at all. The machine is always sending the same signal into the ground regardless of sensitivity setting. I believe what it affects is the DSP algorith in the machine that affects the accuracy of the TID (both visually and aurally). The post was interesting as several questions were posed to a Minelab engineer and answered in an email. It may have been Jason in
TN who asked--I don't recall.

Thanks for the info guys. Eric do you think this is because of the FBS 2 or something else? I thing I am going to do a little more dirt hunting with it before the beach again. I am thinking this will help me learn just whats going on with this machine.
BCNJ

 

[Reeseb]

I run as hot as I can stand the falsing on land and in the water. I'm usually at 30 on land and 28 in the water. It's easy to tell a target from falsing once you get used to it.

 

[Erik in NJ]

The FBS 1 & 2 are the set of frequencies (and rates) that the machines cycle through. The CTX has a more powerful and faster processor than the Explorer & Etrac with better algorithms, thus the better stability and TID accuracy. What sensitivity is really doing is filtering what the machine's DSP algos see as "noise" be it from iron, multiple targets, mineralization, EMI, AND weak targets interestingly enough. It is a threshold per se that allows a signal to be registered. The gain setting is what allows you to hear deep targets as louder or softer relative to their depth. Think of it as a depth variability. At max gain deep and shallow target will produce signals at approx the same volume. The lower the gain the bigger the delta in volume. I prefer my deep targets "sounding" deep...of course they could have added timbre as an added sound dimension, but despite all the advantages, they still seem to have let some great possible features slip through the cracks. My CTX is on the way and I'm sure it will be a fine machine. The auto sensitivity + x is the setting I like. Even the Explorer SE runs very smooth in auto. Hope this helps!

 

[etracjoe]

A friend of mine told me that after speaking to a minelab engineer that was using an etrac at the time said "i dont understand why anyone would want to run the machine in manual? The etrac should only need to be run with an auto plus x offset. It is way more intelligent then we are able to keep up with it in manual and it is not just adjusting sensitivity but also way more then most would comprehend" Now granted this was with the Etrac but I'm sure same theory can be applied to the CTX. I know some will disagree but for me I pretty much always use auto plus 3. I also used auto plus 3 and sometimes 2 in the water with no issues. Just had to turn gain down a wee bit. I have no issues hearing targets that others pick up using manual, and in fact they tend to sound a little more crisp. The tid is more stable too. Sure I can use manual and I have......the other reason why I don't is because as stated earlier you have to check the false signals if your running too hot. I sometimes can tell the difference from a false to a legitimate target but why bother when the machine can do it for you? And to go a little further, I have also ran the silver program using pattern 1 in auto plus 3 at a park and it sure plucked the good targets out of the trash. My only issue at said park is I only dug deep targets there (wich were few and far between) when most of the silver and other good targets were within 3-4 inches. Thats why my buddy came home with a full pouch and I did not. He was also using the CTX. These parks were hammered over the years by other detectors, but when you see the lawn litteraly covered in trash you know why they have such a hard time picking out the good stuff. Welcome to NY.

 

[Digger]

Here are some exerpts from previous posts I've made, regarding manual and auto Sensitivity.....

Auto Sensitivity software was designed with three separate signal channels (high, medium and low). These three channels are used to measure magnetic ground interference that affects these channels, and automatically adjust the Sensitivity individually to provide the most stable TID for each channel. When using Auto Sensitivity, the left bar and numeric value indicates the highest Sensitivity Level that either the high, medium or low channel is operating on. The right bar indicates the "Suggested" Sensitivity Level, as determined by the CTX 3030. This "Suggested" level is the average Sensitivity Level of the high, medium and low channels. Each channel is set to a different level of Sensitivity individually by the CTX 3030 to provide the most stable TID's. As an example....... if the CTX 3030 determines the Sensitivity Level for each channel is to be High = 20, Medium = 17 and Low = 11, the left hand bar and numeric indicator will read 20, representing the highest Sensitivity level of the three channels. The right bar and numeric indicator will display the average of the three channels, which is 16. 20 + 17 + 11 + 48, divided by 3 = 16. When you implement the Auto Sensitivity offset with an offset of +3, it will not suddenly change the value of both bars by 3. Instead, it increases each channel's value by 3. So in the example given earlier, the channels will become High = 23, Medium =20 and Low = 14. 23 + 20 + 14 = 57, divided by 3 = 19. So the left bar and numeric indicator will display 23, representing the highest Sensitivity level of the three channels. And the right bar and numeric indicator will display 19, the average of the three channels. When using an "offset" the numeric value of that offset will also be displayed in a little icon, to the left of the left Sensitivity bar.

In Manual Sensitivity, the left bar and numeric indicator represent the level you have set. The right bar indicates the "Suggested" level, just as it does in the Auto Sensitivity mode. The primary difference between using Auto Sensitivity and Manual Sensitivity is that in Manual, ALL three channels are set to the same value. In Auto, the CTX 3030 determines the value most stable channel. Auto Sensitivity with the offset allows you to "offset" each channel by a value from -3 to +3. The offset allows the user to be more conservative, or aggressive than the one chosen by the CTX 3030, while allowing it to "compensate" for ground interference changes during your hunt.

 

[earthmansurfer]

etracjoe - What I found from testing over 50 coins (I estimate) at 8" plus, in manual 30 (on the E-Trac), is that auto +3 will hit on 95% of them IF the auto +3 level is above the 23 or so level. So, you are probably safe to run auto IF the level is near the "boost level" of around 23 or so. In a few extreme cases, auto +3 at 25 - 27 would not hit what manual 30 would hit. That said, manual 30 would usually hit harder anyway than most auto levels but not enough to miss a target.

As others have said, you can easily get used to falsing. When my CTX falses, first, it's not bad (I wouldn't go through that) and second, it is extremely easy to distinguish.

I agree that the auto feature is smarter and or quicker than a user can be, but to get that last 1" or depth or so, requires one to be running hot, either in auto or manual. And sometimes it is not possible to get it that hot in auto (but it is in my ground.)

The thing about running in auto is that if a coin is just beyond the range of auto, you will never know it. When running in manual (if nothing more than just a test) and cross checking in auto, you will see which coins you will or might have missed. But again, this is a small amount of coins but I imagine it varies from location to location though.

If the ground is pretty trashy or super high in iron content, I will back off manual and actually just run it in auto.

Albert

 

[etracjoe]

If the ground is pretty trashy or super high in iron content, I will back off manual and actually just run it in auto.

Albert

This is most places I hunt and do agree to most you say "in your ground". Coins are usually not deeper here then maybe 6 inches but lay in extreme trash and iron. Some sites I go have deeper targets but are less trashy and then I switch to check targets and if it runs smooth enough in manual I will stay for awhile.

 

[Big Boys Hobbies]

I try to run as high as I can but remain stable. I found Auto +2 worked well for me on the beach. I am sure Minelab had a reason to say to not use it. Cant figure out why though.

 

[Buried Crap NJ]

Eric, In your post:"I prefer my deep targets "sounding" deep..." I do too. I have yet to hear a target that wasn't a loud blaring tone. Be it in my nickle bin or silver bin, regardless of depth. Being on the beach we tend not to really not pay attention of the depth as we just scoop once twice three times. Could it be that the matrix of the semi loose sand allows better penetration then in hard dried dirt conditions. Dirt hunters seem to be so happy to pull a coin out of 12 inch holes. 12 inches in the wet sand is a normal coin range, with heavy Gold and Platinum being down in the 18in range. I guess I am having trouble not hearing what I tend to belive is a deep target, cause all my targets sound the same volume.I have had some 2/3 scoop recoveries, but they all sound off like surface finds? What I have found is that the deeper the target the less reliable the TID tends to be.(exspected)Tones still hold true to a good target. Where's the blip that produces finds dreams are made of? Is it that the 3030 is just a multi tone beep and dig machine? ( that's a question, not a jab at the 3030) Can i set the machine up better to make deep targets sound deep. My gain is 20 deep on,multi tone fe line 24.
BCNJ

 

[BarnacleBill]

"Cant figure out why though."

I have no inside information, but I can see under certain circumstances it could be problematic. Auto Sensitivity has to operate at a given sampling rate, in other words take a ground noise sample every 1/4, 1/2, or 1 second etc. What the sample rate is I don't know. There is likely also a rate of sensitivity change that is allowed or disallowed. Let's say the ground sampling rate is once a second, and the most the micro-controller is allowed to turn the sensitivity up/down after each second is 3 points, then sample again and add or subtract sensitivity.

Whatever the sampling/change rate is I can see the major problem as being the use of it in the surf. Saltwater is like liquid metal, almost easier to think of it as liquid Mercury. If you are in the breaking surf zone you have liquid metal washing over the coil. The wave interval, wave depth, and salinity are going to constantly vary all over the place. An auto sensitivity circuit is going to have to chase that liquid metal conductivity constantly which could kill performance and create falsing.

That's my theory and should not be taken as factual.

BB

 

[Erik in NJ]

That's what I don't like about the high gain settings....all targets are blaring in your ears almost as if they are surface targets. I also find that the excessive volume causes ear fatigue which also limits the duration of my hunts. I hunt mainly by sound until I hear what I am looking for and then I look at the screen--I don't want to have to constantly monitor my screen. I have not received my CTX yet, but the theory of a number of these setting is the same as on the Explorer and e-Trac, both of which I have. The default gain setting should be OK, if not find a deep soil target and crank down the gain setting one notch at a time until you like the sound. My hearing is not super stellar these days (probably in part from listening to the squeals and squacks of the Explorer at too high a volume for so many years), but the softer sound of the deep targets sure gets my attention fast! I don't run with "Deep On" as this setting should have had it's name changed once and for all...everyone believes it makes the machine "go deeper," but that is nonsense and even some Minelab reps don't understand it fully and are confused. It applies a non-linear gain to the deeper signals, so try turning this feature off. I run with Deep Off and Fast Off and deep targets have that special "deep" sound that I look for. Hope this helps!

 

[Buried Crap NJ]

Ok great info Eric. Its this type of posting that helps others step through the learning process.
And Barnaclebill, I talked with a Minelab rep early on about beach use and auto. It was he who said the machine can not keep up to the frequent changes in and about saltwater. You might just be on the right track as to why?
I only turned the gain up when a post said you could hear deeper targets. But while that may be true, it has an affect on volumes of targets both deep and shallow. I would rather have a volume change than have them the same. It ussally takes me a year before it just pops and i finaaly get it.
BCNJ

 

[greenmeanie]

I also run with deep off and fast off.
I want to really know how deep those targets are by sound not by amplification.

 

[earthmansurfer]

I like to use a gain setting of 23 or so. I think we need to use some gain on deeper targets. No amplification at all would be a gain of 1, per the instructions:

With a setting of 1 the target signal will not be amplified. Weak target signals will sound quiet, medium target signals will sound mid-range and strong target signals will sound loud. There will be greater differentiation between target signal strengths; however, weak signals will be harder to hear.

Now, when I dug a nail at 12" or so, I could barely hear it with a gain of 23. So, that told me that I need to be careful with deep targets and too low a gain. I don't know on coins at that depth if they will even sound off in my ground but I think the best thing to do, and others have mentioned it, is that once you find a very deep target, drop the gain to a level you like and then just stick with it. I do have to do this on a deeper target again.