E-Trac - Discrimination vs. Depth

For those who use the E-Trac and like to heavily discriminate out possible targets . . .

Testing = Air tested, two-way repeatable signal, 11" DD coil.
Heavy DISC = SmartFind screen all Black (DISC) except about 10 pixels
Light DISC = SmartFind screen all White (open) except about 10 pixels

................................Heavy DISC..................................Light DISC
....................AUTO+3 ....... MAN-30 ..................AUTO+3 ....... MAN-30
Dime ...............6.5" ..............8.0" ......................... 7.5" ................10.5"
Penny .............7.0" ..............8.5" ...........................8.5" ...............12.0"
Nickel .............7.0" ...............7.5" ..........................8.5" ................11.5"
Quarter ...........7.0" ..............9.0" ...........................9.0" ................12.5"

Depth increases as compared to using the Heavy-DISC with AUTO+3.
................................Heavy DISC..................................Light DISC
....................AUTO+3 ....... MAN-30 ..................AUTO+3 ....... MAN-30
Dime ...............6.5" ..............123% ....................... 115% ............162%
Penny .............7.0" ..............121% ........................121% ............171%
Nickel .............7.0" ...............107% ........................121% ...........164%
Quarter ...........7.0" ..............129%" .......................129% ............179%

Upshot: Using too much DISC will harm the depth targets can be acquired. Switching from heavy to very little DISC can boost depth by as much an average of 22% in AUTO+3 and 41% in MAN-30. That is, keeping all things equal (other settings) radically reducing DISC on your SmartFind screen can increase useable depth by 1/5 to 2/5 more over a heavy DISC AUTO+3 screen. This is just by changing DISC amount, not changing Sensitivity settings.

Even better is switching from AUTO+3 to MAN-30 and dropping heavy DISC to very light DISC. In this case you'd improve your useable depth by an average of 69% or to say it differently -- such a change would permit more than a 2/3 greater useable depth on the E-Trac.

Some food for thought.

Great information. It takes a lot of time to compile information that is accurate.
Nevertheless, some of my test show a possible increase in addition to yours when certain noise cancel numbers are chosen over others. But the different channels can only be used in low EMI areas, else there is a reduction of depth very close to the increases you have shown. It takes a lot of practice to run this machine in manual 30 sensitivity, mainly because of the amount of falsing one usually encounters. I usually run in auto +3, then when I locate a very deep or iffy target I'll switch to manual sens and see if the audio improves.
The Etrac is a very good machine, good depth and easy to use without any complex adjustments. Thanks for sharing your information.

There are many places I hunt though where manual 30 is flat impossible! Sometimes I can make it to 21 or 22 but beyond that it's a constant roll of sound, without break!

I recently upgraded to the CTX. Too much sensitivity creates to much falsing. The ability to interpret the sounds becomes too much to deal with. First rule of my detecting is to enjoy myself. An unstable detector does not allow that to happen. Using the E Trac quickmask can be a very useful tool. The change of discrimination at the push of one button.

Yes, I have already noticed that when I hit an iffy, one way signal in COINS Pattern ( sens at Auto +3) and then hit the Quickmask button, the target becomes much clearer. I then watch for the little cursor and see which way it moves. I can also run fairly quiet with Sens at 27 in the yard i was hunting today, (found two Mercuries and an Indian head by the way....yea me!!!). But I didn't realize that the Coin's Pattern (which is pretty heavily blacked out) would hinder sensitivity so much. I bet that the Relics Preset Pattern would be a good one to use that would not hinder senitivity. Just have to keep a good ear for the hi tones and watch the screen I reckon.
But the Etrac really made a believer out of me today...especially with the deep Indian Head (close to 9 inches according to my propointer). It showed us in the coin pattern as 10-30. I dug it thinking that it was a bullet!!!!!!!! Out popped the Indian head. Sometimes, it seems, the numbers cannot be trusted. But the sweet, two way, and at 90 degrees, signal compelled me to dig it regardless. Glad I did.

Thanks for the info Johny. The heavy disc pattern you are using, is that basically just a few coin windows opened? The only time people would use a mostly all blacked out screen would be in heavy heavy trash - where depth isn't really possible. Right?

I think another test, perhaps more realistic, would be to compare the stock coin pattern with a minimal disc pattern (just the lower right corner of the screen, perhaps one line on the bottom and top as well). I don't think there would be as much of a difference between the two. Just a guess, but I hunted with the coin disc pattern for 20 hours and then minimal disc from then on out (80 + hours) and I didn't see that I was getting any deeper.

Albert

Agree. I'd like to see the identical test run "stock coin" program vs. "minimal dsc" program.

Goodmore, could you perform one set of tests using a dime with your CTX?

Thanks in advance!

goodmore Wrote:
-------------------------------------------------------
> I recently upgraded to the CTX. Too much
> sensitivity creates to much falsing. The ability
> to interpret the sounds becomes too much to deal
> with. First rule of my detecting is to enjoy
> myself. An unstable detector does not allow that
> to happen. Using the E Trac quickmask can be a
> very useful tool. The change of discrimination at
> the push of one button.

In my area (minimal EMI), I was able to run both the CTX and E-Trac with manual sensitivity on max. I wouldn't say the CTX was any worse than the E-Trac, maybe by a point or two, but pretty close (I ran the E-Trac on 30 manual and the CTX on 28-30). I do agree that enjoyment is primary, which is why I mostly shy away from audio overload in TTF and the like.

I have "doubts?" about the depth of my ETrac. I to, like to enjoy my hunt so do not run my Sensitivity at 30 or that neighborhood. Plus, I use a modified Minelab Stock Coin Pattern (which is opened a bit more). Usually running in Auto +2 or 3 Sensitivity. I have run around 25 Manual Sensitivity after I have seen what my ETrac was running while in Auto.
After a year now, I am beginning to have doubts about its depth ability.
I read one of KevinB's post and he stated this "most recent ETrac he bought" is deeper than a former one he had/used.
NOW, Im thinking, I have a dud,lol.
I use to have a small coin garden, but we moved a couple years ago and I just havent made a new one,me being a bit lazy. And I do have a question on coin gardens, but I will make a different post on that.
I for the most part have settled down to using my ETrac in parks or school yards. I had terrible experiences with it in nail,iron rich environments in the old farm fields where a old home once stood. I think with the latter is mostly my fault as I always tried to run it hotter that I should have. But, I can always go back but I really feel in these type spots I am getting better service from my F75se.
I am open to suggestions,ideas, something new on settings.
I havent run in TTF as JohnnyAnglo, in the parks and school yards. I did use TTF out in the fields.
But, I do know this, and I am sure you do to, IF, I do carry it back into these fields with all the iron in the ground, I will have to run a much lower sensitivity because the falsings are terrible ( I read where some run it hot with success and I just cant see how they endure it and leaves me questioning if maybe my ETrac is a dud). Also in these fields, I have mostly open pattern, trying to disc out only nails.
GAIN, also will some of you give me your use of Gain. I have read where to much Gain has a detrimental effect on the ETracs operation. As of late, I have been using Gain at/around 20.
Merry Christmas,
John

Johnny thanks for sharing your info as it certainly gives us ballpark info. Unfortunately not sure if all units are equal and dial in your neck of the woods info can change.

A little experimenting by each owner usually gives him an idea of what works best in ones particuliar area but certainly good info as a guideline and well the unit is not learned overnight and time in the field and experimenting goes a long way to becoming proficient with unit in hand...

I want to apologize, I got carried away.
Johnny, thanks for that info. you have shared with us.
John

I run gain at 17, stock coin program.......sens. at 25...and I get real good depth here in California.to me having the gain at 17...makes it easier for me to tell depth and makes it easier to run sens. at 25....



Edited 1 time(s). Last edit at 12/16/2012 03:43PM by mascard1.

Johnny, THANK YOU for your labor-intense efforts. It is exactly this kind of data that is most useful to the detectorists that are more advanced than 'hobbyist/apprentice' status.

This kind of data is shunned on other forums....... especially if it implies any form of head-to-head comparison.

I must also say that: having a 'bench' with standardized 'test-standard' targets and 'standardized detector performance' data........... is paramount in determining whether a detector is on par or is sub-par. This is also to say that ... you can keep an eye on any type of 'performance shift' .... should something start to go bad with the unit.

Just got back from a hunt in a new to me park and tried a little experimenting. I really lost the ability to hunt with any effectiveness beyond manual sens 22. Just constant random noise. Auto plus three was running at 19. I was hunting in manual sens 21 and I was using a Detech Ultimate 13 coil.

At any rate I was using only a moderate amount of disc. Mostly 27 and below FE. Got a very solid sounding hit that while a little bouncy was averaging 12-47 and showing 10" or so depth. Turned out to be a silver 1943 Australian Three Pence at a measured 9 1/2". Before digging I tried it in Auto +3. Sound was a little sketchier and numbers a little more bouncy but still something I would have dug. Cranked up to 30 manual sens and the cacophony of sound had the signal in it but it would have been hard to tell what it was and whether it was worth digging.

I'd love to find a place I could hunt in manual 30 but haven't found one yet. but pumped to the limit does seem to make a difference on fringe targets.

I wonder if there is a big difference in how the detector runs with the stock Pro Coil and the Ultimate 13. Maybe next hunt I'll take both along and see what the difference is. As a purely subjective observation the Ultimate seems to run higher Auto Sens in the same areas as the Pro Coil. This forum will probably drive me to take both along and make sure!

Just my less then perfect observation from today!

John --

I would be glad to chat with you about some of your questions. I hear frustration, and I understand. A chat on the phone, though, would be easier than on a keyboard. Let me know (via PM?) if you'd ever like to chat on the phone. I run an Explorer SE Pro, which is quite similar in many regards, and I also have time on an E-Trac.

Using heavy disc CAN INDEED cut down on detection depth -- NOT due to anything "electronic" per se, but more based on the fact that if your disc pattern is too "tight," you will miss some deeper targets BECAUSE deeper targets will often not ID as accurately as shallow ones (especially in "non-mild" soil). On an Explorer or E-Trac, deteriorating accuracy of target ID with depth means that, in a tight disc. pattern, these deeper coins will become mostly a "null" in the threshold (i.e., they are being discriminated out).

For me personally, I find the best "deep coin" hunting style is to run high sensitivity (as high as possible until iron falsing just becomes overwhelming), in conjunction with a very open Iron Mask (in your case, quick mask), just enough to knock out targets that are most certainly iron...i.e. targets that ID very solidly into the iron range. THEN, I use a lower-than-maxed-out gain. Reason being, a maxed-out gain means ALL targets, shallow, deep, big, small, whatever, will sound off with the same volume of audio response. With high sensitivity and little discrimination, this is NOT GOOD. You will be barraged with loud tones. But, lowering gain progressively makes deeper and/or smaller targets sound quieter than shallow and/or larger ones. SO -- while the high sensitivity and very open disc pattern WILL introduce alot of "noise" into your headphones, the lowered gain setting allows you to learn to manage the "noise." Over time, you can train yourself to "tune out" the constant, loud, high-tone chatter -- as most of these LOUD targets are either SHALLOW or LARGE, and thus, if deep-coin hunting, can be IGNORED. When hunting in this style, what you are listening for are the much softer, quieter, more subtle tones. When I get one of these more subtle, quieter tones, I will stop and work around the target in a circle using the "Minelab wiggle." If I find the tone to be solidly repeatable from all directions, I will dig it (in spite of whether or not the ID falls where an air test would say it "should.")

Steve

First and again, Johnny thank you, I certainly didnt intend to hijack your thread.
I agree Tom,110%. I do not have anything atm to measure its performance.
I just have not found anything deeper than around 7 inches, 6 for certain. Maybe I just havent crossed over a target yet.
But, thanks!!!!
I will put in another coin garden, just seems I stay so freakin busy, and when I get spare time, I go hunt. And I want to use the pvc, and glue coins to that.
Steve, I will give you a call, I have talked to several others over several months that have used the ETrac exclusively.
Thanks,
John

**** The heavy disc pattern you are using, is that basically just a few coin windows opened? The only time people would use a mostly all blacked out screen would be in heavy heavy trash - where depth isn't really possible. Right? ****

The nearly completely black SmartFind screen was done for testing purposes. It only allowed the subject coins to sound. Likewise, the open screen was just to get a record of the opposite case for comparative purposes.

In TTF, most ferrous will sound as low-grunt tone anyway (18-35Fe) - so no big gain in blacking out above 17Fe. Keeping the DISC'd area smallish to gain depth would mean using DISC only where necessary.

For instance, the E-Trac stock Coin Pattern uses 935 discriminated pixels to remove audio for iron below 16Fe, that's a bunch of DISC. The E-Trac High Trash Pattern and City Park Pattern uses more at 985 DISC pixels for the same purpose (not including other DISC'd areas near the screen top).

The pattern below uses 229 DISC pixel to silence nails/iron (over 4x times less DISC use than stock programs) while relying on TTF to low-grunt on everything above 17Fe. The common low Fe wrap-around iron/bottle caps are removed and low Co foil is also discriminated while allowing thin rings to bleed through. Don't need hot rock protection so the rest is left open. Anything hitting in the open area and giving a HIGH tone just requires a glance at the TID to confirm - should be enough to know if it's worth digging (repeatable and/or in known/likely target area). The open 35Fe-38-42Co is for the sake of steel pennies - should you ever hope to find one (it will permit some nails to sound off).



I like to keep VOL GAIN low (10-14) so the weak target stays sounding weak - it is bothersome to hear a crisp high tone that implies shallow - then dig 12" before uncovering the target (yes, the depth gauge would help but the initial tone is deceptive as to the depth - so VOL GAIN must stay low).

Keeping Tone ID Variability high (24-26) will drive the low tone lower and the high tone higher - helps create a more distinct tonal variation in TTF.

For quiet running I use Auto+3. But to test the area I'll check the LEFT sensitivity bar (gives max of all three channels) and switch to Manual and start with a value near that MAX. From there you just up the Sensitivity until it falses on nails or chatters too much - and then back it down a bit until it settles. If you end up back where the left sensitivity bar originally had it - then go back to Auto+3.

You can always repeat this procedure as you move around and ground conditions change. There is useful info from the RIGHT sensitivity bar - it is the averaged value for all three signal channels. If the right bar is way different while in Auto+3 guess what that means? It means at least one other channel freq is not liking the ground and running in Manual is probably going to be a problem under those conditions (Manual will drive all channels at the same level - and whichever one brought the average down will be the channel(s) that causes erratic behavior while in Manual). So, if in Auto+3 the bars are not near each other (bars are separated) just remain in Auto+3 until they get closer (if they ever do - which again depends on soil conditions).

Thanks for the added information.
Never had the thought of lowering the volume gain to the level you mentioned, but I'll try that in my test garden when all this rain quits.
Thanks again for taking the time to post your observations.

Nice info Johnny
Do you see ant difference with Deep on versus Deep off when doing this test?



Edited 1 time(s). Last edit at 12/17/2012 02:45AM by docbars.

Thanks for the further description Johnny. I'm still curious about the depth difference (if any) between the stock coin pattern and a minimal disc pattern. I can imagine there being some as you alluded to, since the stock coin program is kind of on the heavier disc side. I just never noticed that I missed any deeper (8" - 9" in my ground) fringe targets switching between minimal disc and the stock coin program. That said, I do bet it can make a difference on some targets. The reasons why your testing showed a loss in depth with high disc could be many?

Something that might be worth mentioning is the "trash density" setting being on "high" when running disc (or not). The instructions state the following regading trash density set to high:
"
In High setting, E-Trac searches for the best accepted target signal during detection and then displays the most stable Target ID. The High setting allows you to detect accepted targets in the presence of ferrous objects, high ground mineralisation or amongst a number of rejected targets.
For example, when a coin is buried amongst nails and you are using a Disc. Pattern that accepts coins and rejects nails, the detector will lock onto the coin and the Target ID
for the coin will be displayed at the end of detection. If the nail produces a stronger signal response the detector will not blank at the end of detection, and the Target ID for the coin will be displayed at the end of detection.
It is recommended to use High in areas with high trash and where a “good” target may be masked by the presence of many ferrous objects or high ground mineralisation.
In a High Trash Density setting the Target ID is more unstable, therefore, a greater number of Target ID numbers need to be used to reject a specific target.
"

Markg and docbars - since you both mentioned an overlapping topic, let me jump in. Another poster a while back and on another forum mentioned that the ONLY TIME he saw "deep on" do anything is when the "volume gain" was lowered down to that teen range. I do think that "deep on" responds a bit slower so you might have to adjust your sweep speed but it might also depend on your ground. Also, the idea in the post I read was that deep on would then amplify, slightly, those very deep signals, that you might miss with the gain in the teens. Worth a test. I don't run deep on in my moderately mineralized ground, I tested it on most EVERY fringe depth target (8" - 9") and it made no difference except to be a bit jumpier VID (but barely). I didn't test the volume gain on low WITH deep on much though - need to check this in your ground and I need to further test it.

I do run volume gain lower (17-19) for the reasons stated above - I like to have those deeper targets sound off softer. It is a HUGE aid when hunting in ground with a fair amount of targets and deep targets present.

Albert

Eric................. on many of the deeper targets ............ you may be surprised a bit...when comparing the stock coil vs the 13" coil.

I hope pleasantly surprised!

*** Do you see ant difference with Deep on versus Deep off when doing this test? ***

Nope.

I didn't have Deep On during the test. In the past I've tested Recovery DEEP, FAST, Trash Density, and Ground against each other and found no appreciable differences in air testing depth. Tested Hvy DISC vs. Light DISC against DEEP and again found no difference whether it's ON or OFF. Minelab's naming convention of "Recovery Deep" sounds like "Deeper Recovery" - but it really has no affect (that I've found) on depth. Ditto for Trash Density Low vs. High.

A bit off topic but a note concerning air tests: In air tests with iron nails in the presence of a non-ferrous target the E-Trac is very likely (almost always) going to null. Even with a non-ferrous target (coin for instance) facing the coil - if there is iron in the coil swath the iron signal will usually override the non-ferrous and null the response. You'd never know the coin was there in an air test. Testing some of these setting in the air hasn't shown any ability of the various settings to increase detectability (sensitivity).

However, in the ground I think it a very different story. The ground channel now functions to measure soil and iron reactivity and does work to minimize iron contamination from the signal, at least to the point that non-ferrous can squeak through. In the air - forget 'bout it.

As you know, the ground is a very complex matrix with dozens of factors altering detectable depth and in certain spots a few of these can increase detectability. While it is somewhat discouraging seeing no affect in detectability when iron is in close proximity to non-ferrous in air tests, it is obvious that coins can be found with the E-Trac amongst heavily iron infested areas (do it all the time).

While there is no appreciable depth difference with these settings, in the field, the Recovery,Trash and Ground settings have provided the experiential evidence that they do the things they were designed to do.

Ok, thanks.

The effects of discrimination can be very apparent with targets that are near max target ID depth in-ground. The conductivity value can vary several points, while the ferrous value can move up into the discriminated region. When this happens, the target can be partially discriminated out, causing a broken or very weak signal. This is very apparent with very small, very low conductive targets (like small gold) that are near/at max target ID depth.

Maximum target detection depth in-ground can be greatly affected by adverse ground conditions. There were some park areas where running at manual 29 produced near zero falsing, and deep, silver coins near iron just jumped out of the ground. But there were beach locations where manual 20 caused an enormous amount of falsing, and I’m pretty sure that most detectorists skipped over such areas. Such skipped over areas can be gold mines, and learning how to properly sweep the coil with the right settings can limit the amount of falsing, and produce old coins and jewelry.

The E-trac does allow the user to get an idea of ground conditions by examining the current “suggested sensitivity level” on the right sensitivity bar (current auto sensitivity level can also be used). If the suggested sensitivity level is running very low, target ID detection depth will be greatly limited, regardless of how high the manual sensitivity level is set. Conversely, if the suggested sensitivity level is running high, a very high manual sensitivity level can usually be used with very little falsing (with good coil control; smooth, level sweeps, etc.).

Auto sensitivity automatically adjusts 3 internal signals; a low channel, a medium channel, and a high channel. If one or more of the channels is too noisy, it will automatically lower that channel to reduce the noise/falsing. Auto sensitivity’s strength is its ability to adjust each channel individually, based on current ground conditions.

Manual sensitivity forces all 3 channels to the user defined level, regardless of the noise. If the suggested sensitivity is running low, it still might be possible to max out manual sensitivity and have very little falsing, with a very smooth, level, steady sweeps. But target ID depth will still be very limited.

Detecting since Feb, 2010
E-trac with 18"x15" SEF, 13" Ultimate coil, Pro coil, Minelab 8" coil, 4.5"x7" SEF, Sunray target probe
CTX3030 with 17"x13" DD coil, 11" DD coil