CTX3030 and Auto+3 vs Manual 25 WOW

LawrencetheMDer

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Detector(s) used
Minelab Manticore, Minelab CTX3030 w 11" and 17" DD coils,
Minelab Excalibur II w 10" coil, Equinox 800 (4) w 11" and 15" coils,
Troy Shadow x2 w 7" coil, Pointers; Garrett Carrot, Pro Find 35,
Primary Interest:
Beach & Shallow Water Hunting
Before buying my CTX3030 this week, I had exhaustedly reviewed the literature and read, twice, Andy Sabisch's book on the metal detector. However, I came across the 2 graphs by "Johnnyanglo" on FindMall the other day and a picture is worth a 1,000 words. (No tones on deep targets)

Although via air test, the 2 graphs show how Auto+3 compares to Manual at various settings from 25 to 1. In a nutshell, if you chose Auto+3 over Manual 25, you will be losing about 4.5" of depth on the dime, from 12" to 7.5", and 4" of depth on a quarter, from 13" to 9". Of course, the graphs and depth differences fail to convey increased noise and falsing during detection with the higher Manual settings, increased need to noise cancel, etc.. Nevertheless, the graphs give me pause in automatically using, in my case Auto+3. I'll give Manual sensitivity more consideration...four inches is HUGH!
 

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Absolute rubbish, sorry.
 

Absolute rubbish, sorry.

I agree. I've switched from Auto+3 to all levels of manual and have never found a difference in depth for a wild target. Air tests are virtually meaningless in testing a BBS or FBS machine. They like to have a virgin ground matrix of some sort.
 

That chart is a bit deceiving since the actual sensitivity level that the machine is running at when in auto is not being shown. If he just booted it up and air- tested it without swinging it over any dirt, then it was probably around 19 in auto+3, which would account for at least some of the difference in distance. I've air-tested a clad dime in auto+3 and manual, same place same time, both running at 28 sensitivity. Auto+3 got it at 10", manual at 12&1/2". Still a pretty significant difference. Not sure exactly how that would translate into in-ground depth, or if the discrepancy between Auto+3 and manual (running at the same sensitivity level) would be the same or less on long buried targets. I use auto sensitivity for a lot of my hunting, but manual is my go-to for the deep stuff.
 

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I have a test garden 3 years old with targets buried at different depths, one is a quarter at 18", I can see the target in manual 23, Auto+3 has never seen it. I consistently get much more depth in manual than I do in Auto+3. Works the same with my excals and my sov gt.
 

is this in sand? I cannot get 18 inches..lucky to get half of that with the 11 inch coil and sens up to 27...
I have a test garden 3 years old with targets buried at different depths, one is a quarter at 18", I can see the target in manual 23, Auto+3 has never seen it. I consistently get much more depth in manual than I do in Auto+3. Works the same with my excals and my sov gt.
 

I emphasized air test in the original post, as I understand it's limitations. I think one must realize that the Autosensitivity algorithm would set sensitivity to some level to eliminate noise (chatter, false signals, electro-mechanical interference, etc.). This is why in Auto you hear very little audio noise. In the exact same in-ground conditions, where the 3030 would Automatically set itself to say a Sensitivity of 15, add +3 and your running at 18. If you Manually set the 3030 to 25, you MUST get signals from deeper targets, but at the same time you're going to receive more noise. The real question is how much more noise can you handle in order to get deeper targets?
The last time I hunted w the 3030, 2 days ago, I chose Manual sensitivity at 25 while Auto suggested a sensitivity of 15. After a while I got tired of the increased noise (even after Noise cancel) and turned it down to 20, which eliminated more of the noise but I think I still benefited from the increased sensitivity to deeper targets (all dimes and quarters at about 12" and alum cans at about 20" w 17" coil ).
 

I agree with those who do not like "auto" settings on their machines. Even when there's a "plus 3" option to tack on top of the "auto". Because IMHO the machine will always "dumb down" too much. Much better to let your ears do the deciding of how much you can push towards that ceiling of how high you can go before falsing occurs.
 

I have spent a lot of time in Auto mode, and have found some deep targets while in Auto.

But...any time you hunt with a machine and it is not giving you chirps, you need more sensitivity and are most likely passing by deep targets.
 

I get the same results with my Etrac on a 11 inch dime in my test garden. Auto plus 3 misses it. Manual 25 hits it.
 

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