Auto vs Manual

[KinTN]

Based on the soil mineralization (low-medium) of my area that I hunt in, I know the following works for me.
My buddy and I were out MD'ing at one of our spots, and both running Auto +2. Both CTX's were running a different sensitivity, while only 10' away from each other, but no real thought was given to this at the time. His was reading 28-18 and mine was running 21-18. We were using the exact same stock coil, program/mode/and settings as well. Anyhow, my buddy had located this target, and called me over to verify the depth, as well as the Fe/Co numbers. I swung the coil over the target, and got no audio at all, and only a visual on the display but how many times do we go metal detecting, and look at the screen 100% of the time...I know I don't EVER, UNTIL I get an audio response. So, I set my sensitivity to manual 28, to match his 28 he was showing on his display. I swung the coil over the target again, and almost blew my ears off, and the depth of the target was 11" !!
So I got home that day, frustrated at how many targets I may have missed, because I was running in Auto +2. I went to my test garden, and proceeded with a series of experiments. I found that if the auto sensitivity is below 22, targets from 6" down get missed. When I went to manual sensitivity, and set it to 23, the target signals gave a good audio response up to 6" & 7" but diminished in relation to the targets depth after 7" and responded very faintly at best.
However, those "faint" audio signals would have been enough though to stop me in my tracks, and force me to look at the display, and swing over the target again. When I set the sensitivity to 25, even the targets at 12" gave a good solid audio signal in both directions, and the Fe/Co numbers were more consistent! I ran this experiment up to 30 sensitivity, but could not stand the chatter, and false signals I was getting! I worked the CTX until I found what I call the "optimal range" and that was between 24 and 27.
So, I went out the next day, to take my findings into the field and put them to the test. I ran my sensitivity in manual at 26. I was able to pull 4 silvers from 4 different areas of the field, ranging in depths from 9" to 12"!! To me, that was the proof I needed, and from that moment forward I ran my CTX in manual sensitivity! Now I am not saying this applies to all CTX's across the world!
Andy Sabisch, could have not stressed it more (during his bootcamp), the importance of having a test garden, and to put the CTX to work in that garden, to see what settings work best! I am glad that I did take Andy's advice, and I strongly suggest to others, to do the same! You may find your CTX works perfectly fine in Auto Sens, while working your test garden, or you may find that you need to bump your sensitivity up, in order to gain depth in the soil conditions for your area.

Excellent post! Very informative. Thanks for taking the time.

 

[Justme]

In bootcamp I learned that changing your sensitivity does not boost the power output from the coil. It makes weaker signals heard better

 

[INSAYN]

In bootcamp I learned that changing your sensitivity does not boost the power output from the coil. It makes weaker signals heard better

And that is exactly what we are all looking to gain.

 

[Southwind]

"... did you see a marked improvement with depth, masked targets, or clearly missed targets with previous setup?"

Perhaps. In my experience Manual improves depth quite well and sensitivity to small, weak conductive targets, but does it find more targets? I don't think so.

Good answer!

I think you could hunt a park for a few years in manual sensitivity and then change to Auto +3 and find more and visa versa.

 

[Jason in Enid]

It's really going to depend on how clean the ground is. Running high manual sens doesn't work well if you have high or even moderate levels of mineralization, or if you have a lot of scattered iron targets. In those situations, running the CTX hot will give you a LOT of false signals. It could also give you a couple targets you couldn't find otherwise but you have to deal with a LOT of noise and dug trash.

Clean ground, your auto sens will already be near maxed out so there may or may not be much to gain.

 

[Justme]

I was hunting an old school lot yesterday and could not get my machine to settle down running auto plus 2. Even noise cancelling twice the unit stayed up around 22. I finally switched to manual and backed it off to 15 before I got a steady threshold hum.

 

[Jason in Enid]

I have found places where the EMF was horrendous, and no amount of noise-cancel would solve the problem. Like you did, the only solution is to start dropping the sens until you get to a point you can tolerate it and hopefully still find stuff.

I haven't tried this with the CTX, but I discovered (by accident) that even with very low sens numbers on the E-Trac you can still get great depth. I had been playing with settings in my house one day, so I dropped the sens to about 5 (or something close) so I wouldn't have all the interference while I air-scanned some targets. I forgot to change it back when I was done. My next hunt I spent hours with it like that and was still digging 7-8 inch deep silvers with perfect responses. Once I realized the low sens setting, I change it back, but I wasn't finding anything deeper after the change.

Just something to consider!

 

[Southwind]

My understanding is the difference between Manual and Auto is that Manual adjust all three channels/frequencies to the same degree. That is to say if the three channels being run were 4 kHz, 7 kHz and 11 kHz. they would all be transmitting at the same level. One issue could be ground saturation from unwanted frequencies. In Auto the Noise Cancel determines the dominant frequency by testing to see which channel is going to be most effective/accurate for the current conditions and boosts that frequency above the other two. I would think the deciding factor would be conditions determined by what Auto chooses to run at. In my case Auto +3 runs a sensitivity between 21-24. Turning to Manual 27 generally only gets me more iron false signals.

 

[Justme]

So if it picks say channel three then the frequencies for each individual channel are different? I know they advertise like 28 frequencies but each channel has three or for frequencies assigned? And what frequencies are assigned to each channel?

 

[Paulie]

In conclusion, my take on this is the same as many are telling you on here. Try it. See which works best for you on your ground. But, watch what the machine is
telling you in green. That number is being derived from "ALL 28 CHANNELS" and it don't lie. There is a reason the engineers decided to include that number on
there for you and it is for you to get the most out of your machine as you possibly can. Don't take my word or anyone else's on here. Only you can determine
which is best ON YOUR GROUND.

^^^Very well stated glenn3-88^^^!! I found what worked best for my soil conditions, and suggest to others, at the very least, give it a try as well! It may be the "key that unlocks the detector" or the detectors worst enemy (or your ears for that matter lol). The feedback/input from everyone that has posted here in this thread, is what this hobby is all about...finding "goodies" in the ground, and helping each other out, to do so!

In my test garden, and in the field, I have found that running manual sensitivity between 24-27, that I have found/ received more targets/responses at depths greater than 6"! I even put this to the test again yesterday...upon finding a good target at 11" (manual sensitivity 26-14) I had a solid signal on both sweeps of the coil. I then moved the detector away from the target, went to Auto sensitivity (21-14), and noise cancelled. I swung the coil over the target, and did not get an audible signal! HOWEVER, the target trace on the screen did indicate that I passed over a target! Therefore, had I been in Auto Sensitivity, I would have missed that target!

My conclusion: The optimal sensitivity for my area/soil is between 24-27. Was I able to find more targets? Based on my experiments, yes!

 

[Paulie]

This is what I follow, when doing my experiments in my test garden/field.