Sensitivity

[gjedda63]

Increased sensitivity,does that always means greater depths? Is the degree of depth dependent of how much your ears can stand or do you have other options?

 

[sugar]

it seems that the auto sensitivity is the most stable way to run the etrac the manual sensitivity seems to chatter like a canary on crack and gives off signals that have no relevance so yes sensitivity that is stable will give depth and there are ways to increase the auto sensitivity as just discussed on the post auto senistivity a few weeks ago there is a very interesting video to watch on increasing your auto and also switching to manual for a few swings also seems to bring up the auto sensitivity and the higher the figure the deeper you will hunt

 

[onemore]

Depends upon your ground and the depth of the desired targets. My experience and testing says extreme depth targets at the edge of the machine's detectability come in clearer and more discernable when my sensitivity is 26 or higher. I do not have trouble with chatter or noise - everything I hear is a piece of metal. Just depends on whether my study of the target from different angles and interpretation tells me to dig or not.

 

[NebTrac]

Also depends on how much trash you're trying to punch through. The machine may be getting too much "signal" rebounding back that it is counterintuitive. If you've read Andy Sabisch's on the Explorer or E-Trac this is where the "high/low beam headlights in the fog" example comes in.

I'd surely experiment and see which works the best for you.

NebTrac

 

[Goes4ever]

I have tried manual several times on different sites and it seems to be so chattery, and I get a lot of falsing but when I use auto +3 it seems to run nice and smooth. I am not sure what I would be doing wrong. But I seem to have good luck with auto so I will just stick with it.

 

[stasys]

Increased sensitivity,does that always means greater depths? Is the degree of depth dependent of how much your ears can stand or do you have other options?

simple answer yes. sensitivity is just what you want to hear, because detector all the time works on max-in other words detector send constant max signal to the ground -and only changing sensitivity you increase or decrease what you want to hear. I learned about just this month buy testing what signals detector sends and receives.. very sad that in manual is no simple explanation how detector works. so knowing this I can say use your etrac on stable max sensitivity,I suggest manual. good luck

 

[gjedda63]

Thanks for enlighten me on this guys,I will test this heavily when detecting season opens up here.Best e-trac discussion board in my opinion.

 

[Chris(SoCenWI)]

Stasys,

I think it was Charles(UpstateNY) that provided pictures of oscilloscope traces many years ago. Same results as you, the explorers always transmit at the same power, sensitivity only adjusts the amplitude that a signal must have before it is processed. The whole fog and headlights analogy is very misleading.

Basically sensitivity is used to ignore electrical interference from nearby powerlines, transformers, and other sources of electrical noise. Your coil is a big antennae and picks up electrical interference from its surroundings. Turn you machine on in the house and crank the sensitivity up in manual. It will start sounding like a pinball machine gone mad. No one could detect with a machine sounding off like that.

Generally speaking you want to run the sensitivity as hot as possible. It can make a huge difference. Out in the country or in big parks typically you can run at a much higher sensitivity than in the city.

Auto sensitivity tries to adjust to electrical interference automatically. It doesn't have to do with ground mineralization. The problem with Auto sensitivity is that it cannot tell the difference between electrical interference from signals in the air from real targets as you sweep you coil over the ground. If it is hearing lots of signals it will turn down the sens. Sometimes way to much. On the earlier explorers one could only guess at how far auto had adjusted the sensitivity from where you had it set. On the ETRAC it shows where is is.

Chris

 

[gjedda63]

Interesting, so if I understand you right ,auto sens isnt always a good thing so manual is a more secure option? How about cellphones,would those also affect auto sens to adjust down?

 

[sugar]

i have tried manual on many a time and the results are rubbish auto sensitivity is by far more stable when you begin and until you have some hours under your belt and know what the etrac is telling you there is no other answer but auto i think at least 90 per cent of people will run in auto for the stability so i hope you at least give it a chance if you use the left and right arrows on the left hand side they will put you in and out of manual the top and bottom arrows will increase and decrease the setting of your manual sensitivity settings you will know when you are in auto as when it first comes up a circle will rotate at the top showing the plus figure you have set on your auto say plus 3 you can therfore make your own mind up which is a more stable mode to be in the main thing is listen to everyone and then go out and try a few things good luck

 

[david.di]

Chris, your right where you say that if you:

"Turn your machine on in the house and crank the sensitivity up in manual. It will start sounding like a pinball machine gone mad. No one could detect with a machine sounding off like that."

Here is a good example of someone running the detector REALLY hot and putting up with that confusion. There are some sites I use the same settings. Having a variable volume control on the ear/headphones is the key to not being too affected.

http://www.mlotv.com/view/440/neil-jones-advanced-etrac-program-explained-settings/

http://www.mlotv.com/view/439/neil-jones-advanced-etrac-program-explained-part1/

http://www.mlotv.com/view/454/neil-jones-advanced-etrac-program-explained-part2/

look at this also:

http://www.youtube.com/watch?v=-5O4OP9sUgo

david di

 

[Ray-Mo.]

EMI. The noise cancel feature is for dealing with EMI. Auto sensitivity can and often does change drastically up or down in as little as a few feet if the soil changes rapidly and has little to do with EMI or the lack there of at many sites.Coal cinders/slag is one of the most obvious culprits that will make auto sensitivity drop like a rock all the way down to 3 or 4 in extreme cases.
Lots of minerals in the soil near the surface will cause the sensitivity to drop/suffer and the machine will become unstable and very noisy if the sensitivity level is kept to high in manual.The noise is not always true falsing but rather the machine actually detecting the minute minerals and signaling there presents.

 

[stasys]

i just add, noise cancel better make manual, I can pick a bit deeper on channel 1 on 11 the same target sows like iron. david I think this man on video will have hearing problem in future, how he using his etrac its only point in very old places there small hamered coins and different pieces make low tone and in the ferrous you can miss, because iron sound low too- I suspect he thinks like this, but if in the ferrous variability is min? how it would be?

 

[Chris(SoCenWI)]

For the most part,

Sensitivity was meant to deal with EMI. When you are swinging over a pile of coal slag or other areas that are dense in targets the explorers in Auto THINK this is EMI and start cranking down the sensitivity. Whether you really want to detect at this low of level and how fast it cranks it back up after you get into a cleaner area are the questions. I'm a pretty strict manual sens user for this reason.

All NOISE CANCEL does is shift the frequency of one of the square waves that is transmitted; there were oscilloscope photos of this at one time also. So instead of 28 frequencies of 1k, 3k, 10kHz, etc. It may now be 1.05K, 3.1k, 10.5k, etc. at the first channel shift, and each channel change shifts the operating frequencies a bit more. The explorers listen at each shift point and I'm guessing they are counting EMI events at each shift-(That is why you are supposed to hold the coil perfectly still while Noise Canceling) - and the shift that receives the least noise is selected. Hold the coil next to you headphones sometime and hit noise cancel, you can hear the frequencies change. Now that it has selected the quietest frequency set for the area you are in it might be possible to bump the sensitivity up a bit. I've found that around power lines and most other common sources of interference that Noise Cancel will gain you very little, that the EMI is fairly broadband and there isn't much difference from channel to channel. (As a note, from reading the patents and white papers from Minelab, it appears that different noise channels monitor different number of frequencies, seldom or never all 28 as advertised. It looks like frequencies that are close to power line harmonics are automatically ignored, so channel one might be analyzing 17 freqs between the 1k and 100khz, channel 2- 13, and so on.)

I'm not sure variation in mineralization ever causes the explorers to sound off; but am not positive. The double D coils allows the machines to automatically track changes in ground mineralization. Not sure if I consider coal slag or other man-made deposits to be ground mineralization. Around our fairly recent cabin I can detect and get the normal millions of chirps and thumps that we hear every where man has been, guessing that is every nail, staple, etc. that has ever been dropped. If I get out in the woods away from where anyone has EVER built it quiets right down and sometimes you get a stable undisturbed threshhold for minutes on end, even at high manual sensitivities. That never happens in normal detecting. What I'm saying is the ground matrix 50 yards in the woods has the same mineralization as undisturbed soil 10 yards from our cabin, but world of difference in the amount of targets under the coil. Whether this is true in Oregon or the red dirt of Georgia I don't know.

Chris

 

[wvrick]

Thanks for posting all the good info and videos. This is really a good post.

 

[stasys]

For the most part,

Sensitivity was meant to deal with EMI. When you are swinging over a pile of coal slag or other areas that are dense in targets the explorers in Auto THINK this is EMI and start cranking down the sensitivity. Whether you really want to detect at this low of level and how fast it cranks it back up after you get into a cleaner area are the questions. I'm a pretty strict manual sens user for this reason.

All NOISE CANCEL does is shift the frequency of one of the square waves that is transmitted; there were oscilloscope photos of this at one time also. So instead of 28 frequencies of 1k, 3k, 10kHz, etc. It may now be 1.05K, 3.1k, 10.5k, etc. at the first channel shift, and each channel change shifts the operating frequencies a bit more. The explorers listen at each shift point and I'm guessing they are counting EMI events at each shift-(That is why you are supposed to hold the coil perfectly still while Noise Canceling) - and the shift that receives the least noise is selected. Hold the coil next to you headphones sometime and hit noise cancel, you can hear the frequencies change. Now that it has selected the quietest frequency set for the area you are in it might be possible to bump the sensitivity up a bit. I've found that around power lines and most other common sources of interference that Noise Cancel will gain you very little, that the EMI is fairly broadband and there isn't much difference from channel to channel. (As a note, from reading the patents and white papers from Minelab, it appears that different noise channels monitor different number of frequencies, seldom or never all 28 as advertised. It looks like frequencies that are close to power line harmonics are automatically ignored, so channel one might be analyzing 17 freqs between the 1k and 100khz, channel 2- 13, and so on.)

I'm not sure variation in mineralization ever causes the explorers to sound off; but am not positive. The double D coils allows the machines to automatically track changes in ground mineralization. Not sure if I consider coal slag or other man-made deposits to be ground mineralization. Around our fairly recent cabin I can detect and get the normal millions of chirps and thumps that we hear every where man has been, guessing that is every nail, staple, etc. that has ever been dropped. If I get out in the woods away from where anyone has EVER built it quiets right down and sometimes you get a stable undisturbed threshhold for minutes on end, even at high manual sensitivities. That never happens in normal detecting. What I'm saying is the ground matrix 50 yards in the woods has the same mineralization as undisturbed soil 10 yards from our cabin, but world of difference in the amount of targets under the coil. Whether this is true in Oregon or the red dirt of Georgia I don't know.

Chris

Nice to read your post Chris- something new for me. Thanks Stasys

 

[coolhandluke]

From the E-Trac manual:

"Increasing the Auto Sensitivity Level by +1,
+2, or +3 sets the Auto Sensitivity higher on
each channel than the automatic setting by
the number of levels you select. You may
prefer this if you do not mind a few false
signals, if it means detecting very faint target
signals. It also tends to reduce the accuracy
of Target IDs."

 

[coolhandluke]

Continued:

"Decreasing the Auto Sensitivity Level by

 

[Rick(ND)]

I just not been keeping up with the E-Trac forums like I used to for health reason, but see you posting here and want to know what you think on this sensitivity issue between the Explorer and the E-Trac. I found on the Explorer I did not like semi auto sensitivity as i seen in some areas it wouldn't pick a new dime up on top of the ground if set to high in semi auto. Now with the E-Trac it is a actual auto I read in Andy's book and also see for me it run excellent in auto at a plus 3, so this is where I run mine most of the time. I can see the sensitivity changing over different ground and know if I have to slow down a bit more if I see it changing a lot, but like I say on the Explorer I couldn't use semi auto, but on the E-Trac it works excellent and wonder if you have seen this too.

I think James maybe thinking on a E-Trac soon as he seen all the nickles Tim was getting with the E-Trac while his XS showed pull tabs on the same targets.

Rick

 

[Digger]

Increased Sensitivity does not alway mean increased depth. And there are other options.
The Etrac uses 3 separate internal signal channels to identify targets. High, medium and low channels. When using Auto Sensitivity, the E-TRAC constantly monitors the magnetic properties of the soil and adjusts each signal channel so that it is least affected by the magnetic ground interference. When running in AutoSensitivity, the left bar indicates the highest level that either the high, medium or low channel is capable of operating in, as determined by the electronics. The right bar indicates the average of those three channels. In other words, lets say that the Etrac has determined the best level of sensitivity for the high channel is 24, the medium channel is 14 and the low channel is 10. In this situation, the left bar would indicate a Sensitivity setting of 24, the highest channel setting. However, the right bar would indicate a 16, which is the mathmatical average of the three channels. Note that none of the three channels are actually set at 16. That is just the average of the three channels. When you switch to manual Sensitivity settings, the rules change. When you set your Sensitivity in manual mode, all three channels are set to the same level. For example, if you set your Sensitivity to 24, thinking you were matching the Auto Sensitivity setting, all three channels will be running at a level of 24. By doing this, you are over-riding the Etrac's ability to determine the level where each channel operates most effectively. If the Etrac determines that ground conditions are adversely afffecting the performance, due to an improperly set channel level, having them "locked in" with manual settings can definitely result in false signals and incorrect TID's. With Auto Sensitivity, as the magnetic ground interference changes when I hunt a site, I can rest assured that my optimum Sensitivity setting will be updated, "on the fly". JMHO HH Randy