High tones on screen, but no audio signal?

[Joel Shappell]

I've had an interesting issue with my 3030 recently. While using conductive, ferrous-coin mode, I will see on my screen that I have an iron signal and at the same time I see that I have a high coin signal. Usually in the 12-42 give or take. But yet I only get a low grunt audio signal.

Is this a false signal generated by the iron? Or is there really a high signal in the hole along with the iron? If there is a good signal (coin for instance) and a piece of iron, will the 3030 give a high or low audio signal on a regular basis?



Thoughts?

Thanks in advance for any replies.

Joel

 

[dougj7]

from my experience when using ferrous-coin separation, when I get an iron signal and around 12:42 it has always been iron falsing. page 41 of the manual states in the note on the left side of the page "The Ferrous-Coin setting may not always provide audio". I stopped using ferrous-coin due to the amount of iron falsing I was getting.

 

[earthmansurfer]

Yeah, I can go along with what doubj7 said (except ferrous coin is my primary mode due to it handling moderate iron mineralized ground better than high trash or ground coin.) So, depending on your ground I wouldn't completely discount it.

Also, try digging some of those signals. Yes it does false more but you might find instances and correlations regarding when it doesn't! (And please tell us. ehehe)

You can notice this in the above ground test I did below of a square nail 1" above a dime.

Albert

[video]http://www.youtube.com/watch?v=ylUf0mKzw74[/video]

 

[Mike MD]

I guess everybody is different. I like ground coin for iron infested places in my area. I like the sounds produced from ground coin better than ferrous coin. I have had a lot of hits from 12-38 to 12-45 with an iron grunt on both edges. These where for the most part steady two way signals with the iron on both sides. I hunt with a discrimination pattern until I hit signals like these then switch to an open screen. It seems to pick up both signals better. Turning 90 degrees I might get a good signal every other swing. Target trace pinpoint shows both the iron and the coin but iron will always stay for the most part when I move the coil. Only the coin signal disappears. I have been sweeping the good two way signal moving forward then back looking for where the coin hit disappears then digging in the middle. (If that makes any sense).. For the most part they have been wheat pennys around 7 inches deep. The one thing I always make sure of before I dig is that it's a repeatable signal. Iron falseing has a tendency to be intermittent or disappear. I have also been running auto plus 3 because the ground here is terrible. This works for me. That's the great thing about the CTX is you can tailor it to each individual.

Sorry I got off subject. If I get a signal in that range with no tone I switch from the discrimination pattern to open screen. Then I hear the tone.

HH
Mike

 

[martygene]

Albert, that video is VERY confusing. It seems like we would never be able to find anything good. i cannot figure out how it can get good numbers on an iron nail like that.

 

[Larry (IL)]

Albert did not spend much time on how to eliminate the nail audio but if you noticed when he moved 90 degrees, the nail audio is gone or breaks up. A trick used on many different kinds of detectors to help decide if to dig or not. Also rusty nails in the ground will seem to pinpoint off to the side of where you got your best audio. There are many little tricks used with experience to help reduce the amount of trash and nails that you dig. I still dig some nails but I usually know what I'm digging when I do, I'm just hopeing that I'm wrong. The CTX will let you know when you have a nice deep target that ID's and sounds good in all four directions.

Sure, I have dug some very deep targets that the TID said was good with no audio, but I had a very good idea what was down there before I started digging (relics). Normally I will dig a four way repeatable target at great depths and was seldom disappointed.

 

[martygene]

it looked like the audio was low for the iron but the dispaly read 13-46 and showed up in the good target area as well. so we have conflicting ideas as to what it is telling us. is the audio or display correct? usually i will hear a high tone between the grunts and be pretty sure that there is a good signal in there somewhere so i guess i would have to have both the tone and the display in unison before i would dig.
but I've been using the 3030 for 2 months now and have been doing well but if someone were just starting that video would certainly confuse them to no end.

 

[earthmansurfer]

martygene - After I got the Rutus Jupiter I thought I would do that test with every machine I got as it is a hard test to pass. As I note in the comments, it's an above ground test. The CTX failed it, but in the ground is where it all matters, and that is where it works its wonders. So, I wouldn't weigh on the video too heavily. The bigger issue imo, is the actual situations where what Minelab posted in the instructions ("The Ferrous-Coin setting may not always provide audio") may occur and how we can ascertain when it is actually a coin and not iron. I have heard next to no information regarding those instances. In my experience, running ferrous coin in 50CO, there are just too many good visual "signals" with no audio to warrant digging them all.

Albert

 

[hershey1]

As Larry said above I too have dug some good targets with no audio that were deep. If you are finding targets that are close to the TID on the screen and one comes up with no audio you may want to dig a few to make sure you are not leaving a good target. My experience is they will be deep. If I have deep on I set my gain at 20 if I run a high gain with manual sensitivity I always turn recovery deep off. This may not work in your ground but it makes a difference in my TN red clay. HH