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Iron Bias


strick

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If it makes anyone feel better I do not believe in perfect settings. Both the ground composition and the trash mix are too variable for that. You can in theory get it perfect for this one square foot of dirt, but wander off 20 feet and now things have changed. All you can do is get in the ballpark with the settings and go for it.

None of this should be a mystery to Deus owners. Recovery Speed (Detect Speed) is the same as Reactivity on the Deus. The Deus range is from 0 - 5 and I am betting not many Deus owners ever run at 0, 1, or even 2.

As far as Iron Bias mine is usually going to be set at 0 because the worst that will happen is I will dig more ferrous junk, and that does not bother me very much. I can tell most ferrous by ear anyway. Iron Bias is the equivalent of the Silencer on the Deus and the trade being made is similar.

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2 hours ago, Tnsharpshooter said:

Some interesting comments in this thread.

How about a pic.

abcyu.jpg

You see a nail and a clad dime.

Stack of 2x4s is for coil height guide.

Park 2 factory program used with noise cancel.

Left at speed 6 too, just played with iron bias setting.

Sweeping coil over top of stack of 2x4s, you want to detect dime with sweeping direction down barrel of nail.

What does varying iron bias do?

Good luck finding the dime using iron bias 9.

Now as I lower iron bias, I start getting one way swept tone at iron bias 6 setting.

As I approach a 3 setting I start getting 2 way swept tone.

At zero iron bias I get 2 way swept tone and also the longest tone vs all other iron bias settings.

If a person hunts their sites using say iron bias 6 setting.  IMO very possible to leave finds in the ground.  I am not saying to necessarily run a 0 setting either.

Excellent post ,i agree totally.

Also,as for depth at a fairly clean beach regarding recovery ,lower goes deeper.Im now finding im digging with the 800 at the limit of what i want to dig at ,at a public space.Great machine this 800.

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Great discussion... this is one of the black boxes for me and my 600... I usually run in IB-0, and hear a lot of iron falsing, but I am fearful of running IB any higher and missing targets due to the IB masking them. 

Ran across this video last night.  As with all test videos, there is some liberty taken with the testing parameters, but from a masking standpoint, it demonstrates much that is being said in this thread.  The part that I was most interested in (and not really addressed in the video) was the effect the iron had on high conductive targets when positioned close.  I saw a quarter hitting solid in the mid to high teens on a few of his swings.  This definitely has made me stop and think about what those mid conductive ID's could actually mean in the field.   

 

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2 hours ago, Steve Herschbach said:

Recovery speed and iron bias are two different things getting mixed up in one thread.

The instruction manual is just a guide and not the be all and end all when it comes how to run Equinox. Very low recovery speeds will reduce depth in really mineralized ground. Yeah, for moderate to low mineral ground it’s true you can increase depth with lower recovery speeds but in more intense ground it’s just not true. Also, you are going to increase your risk of target masking. If a low recovery speed misses a target at two inches next to trash that a faster recovery speed hits, which is going deeper?

I have been fighting this and fighting this. My next Treasure Talk blog addresses the issue it is so important. If there is one thing I wish Minelab would change in the manual it is to offer more detail on that page. Minelab does allude to it:

“A lower Recovery Speed, for the same swing rate, will increase detection depth, but may increase noise.”

The problem in bad ground is that noise increases faster than depth not only negating the potential for increased depth but in fact making things worse to the point where targets found at higher recovery speeds can be missed. In very bad ground it’s not “may increase noise” but “will increase noise”.

Many people are shooting themselves in the foot by immediately going to lower recovery speeds thinking it automatically gets more depth. And if the area has already been amply hunted with BBS and FBS detectors, it is an error if the first order. BBS/FBS users in particular seem to want to immediately try and turn Multi-IQ into BBS/FBS which gives up one of the major improvements over those technologies - speed. The presets are where they are for a reason!

Now for Nukem in the U.K. lower recovery speed is obviously helping him. That makes sense on sanded in beaches in the U.K. But hunt with me and no way. The U.K. is not the Western U.S. You have to learn the machine for your own ground.

As far as iron bias goes I learned Equinox without it (most people know it was a late addition) and so for now I tend to set it to 0 until I have more time to play around with it. I am not saying that is the right thing to do. Just like recovery speed there are no absolutes and so I have no doubt I am in turn shooting myself in the foot automatically going to zero. The worst case however is I am just dealing with more ferrous falsing than I need to.

I like this post.

Good insight into ,"Although deeper,Noise also will increase (In Mineralized ground),hence lower speed setting  ,noise = greater depth potential (To hear the target).

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Guest Tnsharpshooter
55 minutes ago, Tiftaaft said:

Great discussion... this is one of the black boxes for me and my 600... I usually run in IB-0, and hear a lot of iron falsing, but I am fearful of running IB any higher and missing targets due to the IB masking them. 

Ran across this video last night.  As with all test videos, there is some liberty taken with the testing parameters, but from a masking standpoint, it demonstrates much that is being said in this thread.  The part that I was most interested in (and not really addressed in the video) was the effect the iron had on high conductive targets when positioned close.  I saw a quarter hitting solid in the mid to high teens on a few of his swings.  This definitely has made me stop and think about what those mid conductive ID's could actually mean in the field.   

 

Correct, Nox ID providecould be in error.

But, it is very possible for an object Nox is lying about ID on, may be very challenging for some other detectors to detect, or they may not detect at all.

Now, what could a person do say to put some better odds in their favor to decide if Nox is lying to them or not?

How about push the horseshoe button.  If no iron tone heard in edge of signal, rotating all the round a sweeping, this would be an odds favorite nonferrous target that has no ferrous near (no guarantee but good odds), so more stock could be put in actual ID, meaning if bummer ID (like for junk) walk, but doing this doesn't tell you if another maybe lower nonferrous masker is lurking.   If iron tone is in edge of signal, Nox has more odds of lying to you, so one could do consider, ID more chance in error, hence dig to really find out.

Now ferrous is not the only thing to cause iron tone come in edge of nonferrous signal.  But still I think this above is some thing to consider in one's cherry picking regiment of electing or leaving targets behind, especially in areas previously productive, with Equinox or other detector models.

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1 hour ago, Steve Herschbach said:

If it makes anyone feel better I do not believe in perfect settings. Both the ground composition and the trash mix are too variable for that. You can in theory get it perfect for this one square foot of dirt, but wander off 20 feet and now things have changed. All you can do is get in the ballpark with the settings and go for it.

None of this should be a mystery to Deus owners. Recovery Speed (Detect Speed) is the same as Reactivity on the Deus. The Deus range is from 0 - 5 and I am betting not many Deus owners ever run at 0, 1, or even 2.

As far as Iron Bias mine is usually going to be set at 0 because the worst that will happen is I will dig more ferrous junk, and that does not bother me much. I can tell most ferrous by ear anyway. Iron Bias is the equivalent of the Silencer on the Deus and the trade being made is similar.

Perfect as that's kinda the way i was leaning..this thread kinda got off topic but that's ok as I'm always learning on this great site...a little extra digging is not that big a deal an I'm looking forward to some great finds with the nox. 

Strick

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Well done video!  Helped me understand recovery speeds MUCH better!

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8 hours ago, SittingElf said:

Well done video!  Helped me understand recovery speeds MUCH better!

If you haven't already also check out these threads:

Take the depth discussion in the video with a grain of salt.  Air tests are great and everything but they fail to take into account ground noise which is a significant factor related to signal-to-noise ratio.  Steve can and has explained it better (and it is also addressed on page 51 of the manual in the section entitled Swing Rate) but basically an air test can't replicate the ground noise that results as you sweep the coil across the ground (another reason why I am skeptical of air tests where the target is moved vs. the coil). 

Assuming you swing at a fixed rate of speed, you will generate a certain level of ground noise.  Changing swing rate and/or increasing recovery speed can lower the ground noise effect and effectively increase the detection signal-to-noise ratio.   While it is true that raw detection depth (i.e., without consideration for ground noise) will increase with lowering recovery speed as shown in the video, the effect is actually less pronounced when you consider ground noise because the detector will see more ground noise at the lower recovery speeds which will reduce effective recovery depth.  There is a sweet spot balance where you can get optimal effective depth by increasing the signal to noise ratio while increasing recovery speed even though raw detection depth capability is going down.  You can experiment with this but the variables are many including: search mode selection, GB variables (manual, auto or tracking GB), type of soil, level of mineralization, soil moisture content, ferrous target density, non-ferrous trash target density, desired target type size, desired target shape, desired target type (composition/conductivity), and frequency mode.  Fortunately, ML has done most of the experimentation for you in the form of the mode recovery speed defaults which for the 800 are mostly setting 5, 6 or 7 and as low as 4 in Gold Mode 2.  Of course, since these many variables I previously mentioned may necessitate deviations from the default for optimal results, ML has provided adjustable recovery speeds. 

Also, using iron bias in conjunction with recovery speed may help to overcome some of the issues raised in the video such as being able to unmask the desired target between the artillery frags. 

Some forum members have seen the need to significantly reduce recovery speed to get desired depth under certain conditions such as at certain types of beaches.  Fortunately, ML saw fit to provide a range of adjustability on the 800 and to a lesser extent on the 600 to cover the outliers in terms of site conditions to meet user needs.

HTH

 

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I gave the surface 2D Yt-test because it shows the other logic and efficiency of coin and iron detector work on a low recovery rate 1  - the coin signal is sufficient long, full and strong, high recovery rate 8 in this case cut signal coins for more times-the detector only sees a smal piece of coin , but the iron signal under the coil is still -strong ...
 

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