aluminum screw cap

jpbundy

New Member
Joined
Oct 6, 2020
Messages
16
i got a high tone on a aluminum screw cap in all directions in the dime range,i did a air test with the screw cap , had a low tone at 2 inches and less
this is with the discovery 3300. i have a tracker iv also
i switched coils ,and did the air test again,now i get a low tone at
5 inches and less, but the tracker iv will give a low tone up to 6 inches.
so it looks like nothing is wrong with the coil with the tracker iv,
so should i be getting a low tone deeper than 5 inches?
anything over 5 inches will give a high tone
 
anyone?

on a air test the discovery 3300 will do 11 inches on a quarter
however,an air test with a aluminum screw cap will get 12 inches.
problem is with the screw cap i get the low tone only at 5 inches
and less.
if i could get the low tone the whole 12 inches would be really great.
from 5 inches up to 12 inches i get a high tone ,which is bad.
my question is why cant there be a low tone the whole 12 inches?
 
This probably isn't the best answer but since nobody else answered.. All detectors will lose accuracy the further the target is away from the coil. Some will up tone, as yours is doing, and others will low tone.
 
thanks for the reply,i just turned the sensitivity down to 3 bars out of 6
that way it only detects down to 5 inches
 
thanks for the reply,i just turned the sensitivity down to 3 bars out of 6
that way it only detects down to 5 inches

It's just my opinion but I choose to just dig them, I would rather get fooled once in a while than loose that much depth by lowering sens.
You will miss out on all good finds below 5"
 
Those flattened aluminum screw caps ring up good on the AT Pro, usually in the 79-80 range and I will dig those signals all day long.
 
First, as a 'New Member' I / We don't know much about you so, how long have you been metal detecting? What type of hunting / sites do you plan to search the most? What are you mainly looking for? Have you had or used any detectors other than the BH Discovery 3300 or Tracker IV, and if so, what were they?

jpbundy: said:
on a air test the discovery 3300 will do 11 inches on a quarter
however, an air test with a aluminum screw cap will get 12 inches.
problem is with the screw cap i get the low tone only at 5 inches
and less.
And what did the Quarter do at the closer distance? Did it also drop in tone?

Were you holding the Screw Cap in the same orientation to the coil, as if laying flat-to-the-coil, on each test sweep? Were you moving the Screw Cap completely across the coil's width as if being encountered afield, or making a little wiggle type wave of the Screw Cap?

An aluminum Screw Cap is a high-conductive target that should produce a higher-conductive audio response. I would expect it to produce a High-Tone audio, or Mid-Tone, depending on the particular make and model detector and the available audio Tone ID pitches.


jpbundy: said:
if i could get the low tone the whole 12 inches would be really great.
No, it would be really bad because if it is an aluminum Screw Cap, it should be producing an audio Tone based on it's size and conductivity which, most typically, shouldn't be a Low-Tone.


jpbundy: said:
from 5 inches up to 12 inches i get a high tone ,which is bad.
At a distance from the coil to it's maximum detection range it should produce a 'proper' Tone ID based upon it's conductivity, and that means other higher-conductivity targets should also produce a 'proper' Tone ID based upon their conductivity, be it a lower-conductive US 5¢ or higher-conductive 1¢, 10¢, 25¢, etc.


jpbundy: said:
my question is why cant there be a low tone the whole 12 inches?
Because there shouldn't be a Low-Tone for a higher-conductive target at any normal coil-to-target detection distance.


jpbundy: said:
thanks for the reply, i just turned the sensitivity down to 3 bars out of 6
that way it only detects down to 5 inches
Bad move, in my opinion as well as others have started. No, we do not like some of the annoying trash out there, but we have to contend with it. All of the higher-conductive targets, to include Screw Caps, ought to be pinpointed and recovered before we continue on. They have a Target ID read-out in the range of desired targets, and removing them also lets us re-scan the spot to see if they were masking a desirable keeper.

If all was tested correctly, and if the Screw Cap is in fact an all-aluminum object, then you should get a good higher-tone response and it should be recovered. If not, you're going to be missing a lot of very desired targets. If it is such an object and you are not getting a 'proper' higher-tone audio at a closer or shallower depth, there is a glitch with the coil or a definite glitch with the detector that needs to be addressed.

Monte
 
on a air test the discovery 3300 will do 11 inches on a quarter
however,an air test with a aluminum screw cap will get 12 inches.
problem is with the screw cap i get the low tone only at 5 inches
and less.
if i could get the low tone the whole 12 inches would be really great.
from 5 inches up to 12 inches i get a high tone ,which is bad.
my question is why cant there be a low tone the whole 12 inches?

Are you confusing the non-ferrous medium tone with the non-ferrous low tone? Also, depending on what condition the aluminum screw cap is in (smashed flat, crushed and elongated, either has or is missing the locking ring, or just looks normal) the numerical target IDs and accompanying tones may be different.
I have not used a Discovery 3300 very much but I do know it has 4 tones=iron tone, low tone (but higher than the iron tone) non ferrous like US nickels, medium tone for most zinc pennies and aluminum screw caps and a high tone for clad dimes, clad quarters and silver.

If you actually found the aluminum screw cap in the ground that you are testing, it may have had an up averaged numerical target ID and high tone due to being buried deep enough for the ground to raise the screw caps target ID. When you air test it (air, especially air with very little EMI offers only a tiny bit of resistance compared to dirt) and you may get the correct medium tone for the screw cap within the range of your 8" coil which, depending on your sensitivity level, may be around 6". After 5 to 6" the signal strength will drop off quickly and you may get a high tone until the target is undetectable.

Most single frequency Very Low Frequency detectors like the one you have and like many others that cost a lot more will only give accurate tones and target IDs for in the ground coin sized targets to about half to two thirds of their possible detection depth. Deeper than that First Texas, XP and most Nokta Makro detectors will up average or give a much higher tone and target ID. Garretts and some Whites tend to up average to a point and then call deeper coin sized targets iron.

To get around this physics problem, some companies like Minelab, Garrett, Whites and others in the past, made detectors that operate with multiple frequencies simultaneously which in theory can improve the accuracy of deeper coin sized targets substantially. Some of the newer models like the Minelab Vanquish and Equinox can accurately ID deep coin sized targets very well. They are not very good at air testing however.
 
i had a harbor frieght detector years ago and i quickly gave up on that detector cause it kept getting noisey all the time and would constantly pushing that red button.i just got back in to detecting this year with the tracker iv,but after a while i wanted something
with target id.i then bought the discovery 3300. the ground i hunted the most is my
back yard, which is full of trash, and bits and pieces of iron. i still managed to get 103 coins in that 30 x 50 feet area, i went to caladonia state park and got a few coins
but mostly bullets,i dont think they are civil war tho. they are crushed or flattened.
a lot of good information on here.hope im not asking too many questions.
 
Are you confusing the non-ferrous medium tone with the non-ferrous low tone? Also, depending on what condition the aluminum screw cap is in (smashed flat, crushed and elongated, either has or is missing the locking ring, or just looks normal) the numerical target IDs and accompanying tones may be different.
I have not used a Discovery 3300 very much but I do know it has 4 tones=iron tone, low tone (but higher than the iron tone) non ferrous like US nickels, medium tone for most zinc pennies and aluminum screw caps and a high tone for clad dimes, clad quarters and silver.

If you actually found the aluminum screw cap in the ground that you are testing, it may have had an up averaged numerical target ID and high tone due to being buried deep enough for the ground to raise the screw caps target ID. When you air test it (air, especially air with very little EMI offers only a tiny bit of resistance compared to dirt) and you may get the correct medium tone for the screw cap within the range of your 8" coil which, depending on your sensitivity level, may be around 6". After 5 to 6" the signal strength will drop off quickly and you may get a high tone until the target is undetectable.

Most single frequency Very Low Frequency detectors like the one you have and like many others that cost a lot more will only give accurate tones and target IDs for in the ground coin sized targets to about half to two thirds of their possible detection depth. Deeper than that First Texas, XP and most Nokta Makro detectors will up average or give a much higher tone and target ID. Garretts and some Whites tend to up average to a point and then call deeper coin sized targets iron.

To get around this physics problem, some companies like Minelab, Garrett, Whites and others in the past, made detectors that operate with multiple frequencies simultaneously which in theory can improve the accuracy of deeper coin sized targets substantially. Some of the newer models like the Minelab Vanquish and Equinox can accurately ID deep coin sized targets very well. They are not very good at air testing however.

yea,i did did confuse the tones, it was a mid tone at 5 inches and less
the quarter stayed at a high tone at all distants'
i did the wiggle on the screw cap,up close and further with no change
screw cap did give high tone above 5 inches
 
First, as a 'New Member' I / We don't know much about you so, how long have you been metal detecting? What type of hunting / sites do you plan to search the most? What are you mainly looking for? Have you had or used any detectors other than the BH Discovery 3300 or Tracker IV, and if so, what were they?

And what did the Quarter do at the closer distance? Did it also drop in tone?

Were you holding the Screw Cap in the same orientation to the coil, as if laying flat-to-the-coil, on each test sweep? Were you moving the Screw Cap completely across the coil's width as if being encountered afield, or making a little wiggle type wave of the Screw Cap?

An aluminum Screw Cap is a high-conductive target that should produce a higher-conductive audio response. I would expect it to produce a High-Tone audio, or Mid-Tone, depending on the particular make and model detector and the available audio Tone ID pitches.


No, it would be really bad because if it is an aluminum Screw Cap, it should be producing an audio Tone based on it's size and conductivity which, most typically, shouldn't be a Low-Tone.


At a distance from the coil to it's maximum detection range it should produce a 'proper' Tone ID based upon it's conductivity, and that means other higher-conductivity targets should also produce a 'proper' Tone ID based upon their conductivity, be it a lower-conductive US 5¢ or higher-conductive 1¢, 10¢, 25¢, etc.


Because there shouldn't be a Low-Tone for a higher-conductive target at any normal coil-to-target detection distance.


Bad move, in my opinion as well as others have started. No, we do not like some of the annoying trash out there, but we have to contend with it. All of the higher-conductive targets, to include Screw Caps, ought to be pinpointed and recovered before we continue on. They have a Target ID read-out in the range of desired targets, and removing them also lets us re-scan the spot to see if they were masking a desirable keeper.

If all was tested correctly, and if the Screw Cap is in fact an all-aluminum object, then you should get a good higher-tone response and it should be recovered. If not, you're going to be missing a lot of very desired targets. If it is such an object and you are not getting a 'proper' higher-tone audio at a closer or shallower depth, there is a glitch with the coil or a definite glitch with the detector that needs to be addressed.

Monte
i had a harbor frieght detector years ago and i quickly gave up on that detector cause it kept getting noisey all the time and would constantly pushing that red button.i just got back in to detecting this year with the tracker iv,but after a while i wanted something
with target id.i then bought the discovery 3300. the ground i hunted the most is my
back yard, which is full of trash, and bits and pieces of iron. i still managed to get 103 coins in that 30 x 50 feet area, i went to caladonia state park and got a few coins
but mostly bullets,i dont think they are civil war tho. they are crushed or flattened.
a lot of good information on here.hope im not asking too many questions.
yes , the screw cap was giving a mid tone under 5 inches.
it was lower than a high tone
i was calling it a low tone.
 
yea i goofed,i was saying low tone when i should say i got a mid tone on the screw cap

the quarter had a high tone close or far away

i did the wiggle on the screw cap and no differance
 
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