Deep Targets Either Null Out or Not Getting Audio

[flysar]

I've hunted a couple old houses, schools, & parks for a little over 40 hours (youngster I know) and I'm not digging any targets over 5" and I'm still digging it all except for the obvois ferrous. I live in the Northwest in some high mineralized soil, I know this from the GB numbers on an Xterra (14-16) & AT Pro (92-94) I had and I know mineralized soil is tough for all detectors.

This morning while at a park I noticed my threshold null out even though I was running GH combined program wide open and looked at a TID of 11-38/39. So I changed to the stock coins program wide open no difference, maxed out both volumes no difference, dropped my threshold no difference, I turned on auto ground balance with no difference. I did not increase my sensitivity passed auto +3. So I paused the coil waited for the TID to go away and slowly inched toward the null spot and got a 11-37. I dug 2 wheat pennies at approx 6" and there were no ferrous targets in the hole that I could find that would create the null.

I have to run my threshold at 17 to get any audio - either bad ears from 26 yrs flying military helicopters or my old Killer B's are failing. Could that be a reason I'm not getting an audio on the deeper stuff? I do not have another set of headphones to try.

I'm heading out again for a couple hours tomorrow morning what adjustments do you recommend?

 

[INSAYN]

I live in the Great Northwet as well, and have days where it all seems to work great, and days (areas) where the 3030 seems to have a mind of its own.
Our soil is funky to say the least. Some areas are more mineralized than others, and some areas are pretty dang smooth.

I keep trying to run Ground/Coin due to the mineralization, but it is pretty much nulled the entire slow sweep (no threshold) with our without discrimination.
I can switch over to Ferrous/Coin and I get my threshold right back, sweeping over the same exact spot. High trash seems to be better than Ground/Coin for me, but it's quieter and smoother with Ferrous/Coin.

Out in my neck of the woods I don't find very many coins much past 5" with any detector, and I think it is either the ground is too dang hard for coins to drift that far down, or there just isn't any coins in said areas period. With Compass detectors having been made right here where I live, and Whites just a few hours south most public areas have been really milked hard for years.

This fall/winter, I am going to balls up and start knocking on doors of our older houses out here and see if my afore mentioned conclusion is right or wrong.
In Portland I was able to hit several wheat pennies at 8" with nails in the same holes at a private property.
The park right across the street from there only gave up coins 3" or less. Go figure?

Now, there could be something to your comment about digging 6" deep pennies after nothing but nulling over them. Just today I was in a park that very well could be holding old deep silver. 2 hours and all I could muster was a clad quarter and 3 zincolns. I was running combined, F/C with manual sens cleanly up to 28 with the auto suggestion at 14. No crazy beeps and squeaks to drive a guy nuts. Pulled many pull tabs at 4", but no coins past that even. I did watch the screen for a bit and noticed that with excellent threshold, I have penny/dime numbers and an icon painting up while sweeping. Depths anywhere from 3"-12", but no tone or threshold nulls. Not sure if that was just having the manual sens up so high.

We'll get this figured out.

 

[DirtyDeedsDugDirtDeep]

Maybe this will be a dumb question, but have you guys set up a test garden ?????

 

[DukeOBass]

The fix might be as simple as doing a Factory Reset on the machine.

 

[flysar]

INSAYN - OK, so I'm not the only one getting a null with a good Non-ferrous TID under the coil when running wide open, i see iron TIDs as well. I'm about 2 hrs East of you along the Klickitat River in WA. My son lives in Wilsonville and maybe the next time we're that way we can get together and compare notes. One of the reasons I made the jump to the CTX is I figured if this thing can't beat our ground than Im not sure there is a discrimination machine that can. The nulling over targets and showing a non-rejected TID is what has me puzzled. Without the audio it makes it kind of hard to pinpoint and I don't want to spend all day looking at the screen. Ive tried Ground Coin as well because the manual states it is better for mineralized soil but I get better audio and more consistant TIDs when using FE-Coin. I'd say definitely knock on doors... My 1939 rental I'm working on has given up a Walking Liberty Half, Rosie, 20+ Wheats, a silver ring and some clad. I'm in Yakima WA for the next week and for metal detecting the city is a gold mine compared the rural setting of Klickitat.

Dirty Deeds - Thank you for the recommendation but in my soil conditions I've found that buried tests at home dont give the same results, TID and depth, as in the field so I use my hunts as my test garden and because I dig nearly everything right now I've learned a lot. In my few hours I've pulled a mix of targets at various depths - Walking Liberty, Rosie, about 30 wheats, 10k gold band, 2 silver rings, about $20 in clad and numerous screw caps, pull tabs, iron, nails, batteries, junk jewelry, etc.

Duke O Bass - i thought about that but was afraid I would lose my personal programs and since Im away from my home computer for the next week I was hesitant.

I do have to run my headset at near full volume in order to get good audio so maybe my old Killer Bees aren't wired quite right to get the best audio from the CTX, wish I would have brought the factory Koss for a comparison.

Thanks for the reply's.

 

[INSAYN]

Even with a fresh garden, I would have to wait years for the coins to become one with the soil to work any better than an air test.

 

[flysar]

Just returned from 3 hrs at a 1920 home. All modern, 55 memorials, 3 nickels, & 6 dimes. Nothing deeper than 3". I only worked a small section of the front yard to be as thorough as possible and pulled as much trash as possible as well to rule out masking. I talked to the neighbor who had lived there 25 years and he hadn't seen any body metal detecting but it doesn't mean there hasn't been, heck I was pulling silver out of the ground 40 years ago.

I worked the first hour plus using GH program and I couldn't believe I hadn't hit anything deep or old so I hit the big reset button and worked for another 1.5 hours in the stock coin mode. I didn't get any nulling with a good TID but I didn't recover any deep targets either. I won't know if the nulling/TID issue resolved itself until I get a chance to reload my custom programs.

 

["Dr.Tones"]

My guess would be that you either had a large piece of iron under the wheats or that the ground had a pocket of mineralization. Do you recall your sensitivity readings at the time?

 

[INSAYN]

Tonight was an all nail, no coins. Found an old single room school site (1891-1944), that is now a park.
Every signal was iffy, but I dig iffy signals that pin point over the high tones even if they are one way or not completely consistant.
4" Nail
1" Nail
1" Nail
And what bugs me is that even after I clear out 9" deep dirt I start to get a red build under the coin icon and TID of 12-39, 11-40.
I can pinpoint over the hole and it says 6", but there is a 9" deep hole under the stock coil. So, I dig 1 inch to the side where my ProPointer heres something.
Damn nail!

Then it's 1" chuncks of rusty barb wire (straight pieces) at 5-6".

I ran in Auto+3 giving me 18/11 - 21/15. When I ran manual, I could run it up to 26-27 without too bad of falsing. Just enough to know it was running hot.

So, with this finding small 1" nails, and little bits of rusty barb wire at 5-6", can I assume that it should clearly hit a silver dime at 7" provided the coil ever goes over one?

Oh and I swing 4 seconds from left to right, and 4 seconds back. I tend to do a full left to right, right to left coverage before advancing half a coil length.

I really think some of the areas out here have been hit hard since the 70's, and the more recent clad is picked up by more of the current locals before I can get to them.

 

[flysar]

I thought the same thing that is why I opened up the screen and I didn't get any iron tones nor iron TID. I was running Auto +3 and I believe it was 17-19 range.

When the screen is wide open isn't that an all metal mode?

The situation of null with a coin TID happened more than once but I was only able to somewhat pinpoint that one target. If I was in an open field and not a public park I would have used a long handle shovel and dug a big hole to see what was going on.

I need to upload the GH program on my machine when I get home some time next week and see if it happens again. If it does I'll give minelab a jingle.

My guess would be that you either had a large piece of iron under the wheats or that the ground had a pocket of mineralization. Do you recall your sensitivity readings at the time?

 

[Digger]

When the screen is wide open isn't that an all metal mode?

No. It is a zero-discrimination mode. The CTX 3030 has a pre-programmed set of target parameters.... least ferrous to most ferrous & least conductive to most conductive. When the screen is wide open, you are accepting targets whose Ferrous value could range from 01 - 35 and whose Conductive value could range from 01 - 50. If you sweep over a target whose ferrous and conductive values are not within those "least" and "most" parameters, it will not be detected. Accepting or rejecting a set of "numbers" only modifies the Pattern. It does not change the parameters.
JMHO HH Randy

 

[Larry (IL)]

The closest the CTX has for an all metal mode is pinpoint.

 

[flysar]

After a few more mornings of detecting/digging I realized in every yard or park I've hit there is quite a bit of nulling that I must not have noticed before and rarely do I get a TID response but when I do it's normally a coin FE-CO combo and most of those do not give any audio and if there is audio it is very broken or just a blip. There is always the red diamond on the screen along with the good target sign.

I guess I should presume the following;

I have highly mineralized soil and that is why I get so much nulling when running wide open. Some of it may be iron and then again it may be the soil conditions.

On some occasions when I get nulling I get good TIDs 11/12-35 thru 41 but unable, except for the time mentioned above, to accurately pinpoint by trigger or nose of the coil. There is rarely audio but if there is it is broken.

If I can't pinpoint I can't dig so that is an easy decision but I guess I'm wondering how much time would you give to these type targets or what other settings have you tried to improve getting a solid/accurate audio that you can pinpoint?

 

[jas415]

I cant answer regarding soil as I hunt here in the Houston area and the soil is mostly clay and sand. But I hunt 95% on house demolition lots and the metal is scattered everywhere. I very often get the 11-39/40 numbers and a null, splotchy iron smear along with an accepted target, moving slightly away from the area, 3 to 6 inches, and I get a tone along with the numbers. In pinpoint I can almost always find the target to be away from the audible tones and under the iron grunt areas. If I switch from open screen and discriminate, the machine will null over the iron areas and give a tone over the false targets. I dug a bunch of them and they were all rusty nails or screws 4 to 8 inches deep. I run GH's program, slightly modified, normally in manual sensitivity at about 23-27, and I enable the seawater. I also have a bin set for nickels, high tone, and I have dug almost over 400 this year.

My suggestion would be dig a few of the targets, if possible, even down 12-16 inches, just to make sure of the lack of a good target. Also if you have another backup machine what does it do? I personally think you are getting tiny rusty bits of metal with the high sensitivity and it falses on them a bit.

 

[INSAYN]

I was just wondering recently if the seawater feature was turned on if it would help out in the higher mineralized soil or not?