Yesterday was such a beautiful day to detect here in the Queen City...BUT, my detecting partner had to work. So I did something I almost never do. I went to a local park. I thought it would be a good exercise in getting to know better the Omega. The park I chose to hunt apparently has had alot of fill dirt brought in as I was digging pull tabs (round and square very deep...5-7"). Why was I digging them? Because the Omega was ID'ing them as silver quarters TID #'s 89-93. Has anybody else experienced this? If they are shallow they are ID'ed correctly.
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Omega target ID inaccuracy
- Thread starter sekypaleo
- Start date
sekypaleo said:
Probably three factors:
1. iron minerals in the ground throwing ID's off.
2. deep signals are more easily thrown off because the signals are weaker.
3. user technique not quite right for this machine (the tipoff is the 89-93 readings).
Can't do much about the dirt or the depth, but can do something about user technique. With the Omega (and unlike some other machines) it is important to swing broad and level and not too fast. If you try to loiter over the top of the target to "check it out" the target ID will generally be degraded. Depending on your technique, "loitering" or imitating the "Minelab wiggle" will usually drive target ID's consistently up or consistently down.
Another possibility is that you were discriminating out iron and therefore didn't know it was there. Iron located off to the side of a nonferrous target will usually drive the target ID reading up-- what many users call "up-averaging". If you think of this only in terms of target ID, it may seem like a deficiency. However this "up-averaging" what allows the Omega and several of our other products to do such a good job of finding nonferrous in areas with a lot of iron trash.
With old-style analog target ID machines, a circuit going out of calibration can cause systematic errors in ID'ing deep targets, even in air. However in the Omega all that stuff is handled in software and needs no calibration. If the circuit fails in such a way as to impact target ID, the effect will be seen even in air testing and even on relatively shallow targets.
--Dave J.
Excellent question and answer post. I certainly have been guilty of "loitering" over a target trying to get the right ID. My favorite old coin sites are littered with iron, so I understand jumpy IDs around iron. Sometimes I get good IDs going only in one direction. Is this a product of iron masking or a deep coin on it's side? I will usually run the Omega with a disc. setting of 15. otherwise it sounds like a machine gun with all the iron sounding off. Txquest
When you get a good ID going in one direction and not the other, it means that something isn't symmetrical either in the dirt or in your swing. It could be (for instance) a coin with a nail 3 inches away: in such a case when you swing from the side where you hit the coin first, the ID will tend to be near-normal and the iron will be effectively suppressed. On the return swing where you hit the nail first, the nail may break through slightly and the coin ID will tend to up-average. However if the coin and nail are so close that the iron and coin signals cannot be effectively separated by the machine, then the ID of the two things together will drop and may be discriminated out.
A coin on edge will usually give a nonsymmetrical response or double hit, and it will vary depending from what direction you approach it. Our discrimination system used on the newer, software-based products happens to be very good at getting coins on edge compared to most other discriminators but even so it's possible to miss a coin on edge.
If you're hunting a productive coin site, it may pay to hunt the site north-south with overlapping sweeps of course, and then hunt it east-west in order to find the targets that were masked on the north-south sweeps, as well as the coins on edge that were missed. The main reason that productive sites usually keep producing is the stuff still left in the ground due to prior lack of thoroughness. By being methodical instead of relying on luck, over the long haul you'll dig more stuff.
--Dave J.
A coin on edge will usually give a nonsymmetrical response or double hit, and it will vary depending from what direction you approach it. Our discrimination system used on the newer, software-based products happens to be very good at getting coins on edge compared to most other discriminators but even so it's possible to miss a coin on edge.
If you're hunting a productive coin site, it may pay to hunt the site north-south with overlapping sweeps of course, and then hunt it east-west in order to find the targets that were masked on the north-south sweeps, as well as the coins on edge that were missed. The main reason that productive sites usually keep producing is the stuff still left in the ground due to prior lack of thoroughness. By being methodical instead of relying on luck, over the long haul you'll dig more stuff.
--Dave J.
Thanks for your reply Dave, I can say first that my sweep technique is correct in that my coil is always flat to the ground and at a moderate sweep speed. Now, when I get a hit, I DO take the coil back and forth across the target location to try and get a read on it. You are saying this is incorrect? If so then I will have to re-learn 30 years of detecting technique. The park does not seem to have alot of iron ( I run my disc at 16) and the tabs were coming in solid at what silver quarters would read. Why did you state the tip-off is the TID #'s of 89-93. Oh and ground grab is about 65 there.
Sekypaleo,
The "tipoff" is that the readings you report are consistently high, and even tightly grouped. In the absence of other nearby targets, there are only two things I know of that can cause this in an Omega: sweep technique other than "broad and flat", and dialing in so much discrimination that lower numbers disappear leaving only the higher ones. Running disc at 16, you're leaving room for lower numbers. In most ground, that would leave sweep technique. "Broad and flat" requires some self-discipline since there is a natural tendency to try to "home in on" a specific target and to try to get the searchcoil as close to the ground as possible right over that specific target. These habits which work so well in all metals or pinpoint mode work against you in discrimination mode.
If ground grabs at around 65, your mineralization is probably low to moderate unless you're working in red clay. At depths of 5-6 inches in most soils you can expect tabs to bounce around a bit, but a tight grouping of 89-93 which is much higher than the normal numeric value for pulltabs is not something that either the dirt or the pulltab can achieve on its own. If pulltabs are doing this with some degree of consistency, they're getting help.
It's theoretically possible that red clay could provide some of that help, though not likely all of it. Next time you run into a target that you think might be a moderate-depth pulltab masquerading as cash, try momentarily cranking the discrimination down to zero and see what happens.
If the target ID's remain grouped on the high end, it's your swing technique (or a coin, you won't know for sure till you dig) . If they start falling down into the foil range and even iron, then it's the stuff behind the curtain that was making trash go away for you as best it could under the prevailing conditions.
In any case, remember that the Omega is an Omega. If you have 30 years experience (I have 29), that experience may work against you. Machines are different now. The Omega is a very easy-to-use mid-priced machine with big league performance when equipped with the 11 inch DD searchcoil, as you have no doubt read here. It will outperform machines costing twice as much under some conditions. That having been said, there are things that the machines that cost twice as much will do that the Omega won't. There are even some things that certain less expensive machines will do that the Omega won't. Of the stuff we presently manufacture, the Omega is my personal favorite machine regardless of price, but there are situations where I'd use the $60 BH Junior, and situations where an LTD or a CZ would be the only option.
--Dave J.
The "tipoff" is that the readings you report are consistently high, and even tightly grouped. In the absence of other nearby targets, there are only two things I know of that can cause this in an Omega: sweep technique other than "broad and flat", and dialing in so much discrimination that lower numbers disappear leaving only the higher ones. Running disc at 16, you're leaving room for lower numbers. In most ground, that would leave sweep technique. "Broad and flat" requires some self-discipline since there is a natural tendency to try to "home in on" a specific target and to try to get the searchcoil as close to the ground as possible right over that specific target. These habits which work so well in all metals or pinpoint mode work against you in discrimination mode.
If ground grabs at around 65, your mineralization is probably low to moderate unless you're working in red clay. At depths of 5-6 inches in most soils you can expect tabs to bounce around a bit, but a tight grouping of 89-93 which is much higher than the normal numeric value for pulltabs is not something that either the dirt or the pulltab can achieve on its own. If pulltabs are doing this with some degree of consistency, they're getting help.
It's theoretically possible that red clay could provide some of that help, though not likely all of it. Next time you run into a target that you think might be a moderate-depth pulltab masquerading as cash, try momentarily cranking the discrimination down to zero and see what happens.
If the target ID's remain grouped on the high end, it's your swing technique (or a coin, you won't know for sure till you dig) . If they start falling down into the foil range and even iron, then it's the stuff behind the curtain that was making trash go away for you as best it could under the prevailing conditions.
In any case, remember that the Omega is an Omega. If you have 30 years experience (I have 29), that experience may work against you. Machines are different now. The Omega is a very easy-to-use mid-priced machine with big league performance when equipped with the 11 inch DD searchcoil, as you have no doubt read here. It will outperform machines costing twice as much under some conditions. That having been said, there are things that the machines that cost twice as much will do that the Omega won't. There are even some things that certain less expensive machines will do that the Omega won't. Of the stuff we presently manufacture, the Omega is my personal favorite machine regardless of price, but there are situations where I'd use the $60 BH Junior, and situations where an LTD or a CZ would be the only option.
--Dave J.
Jackpine Savage
Active member
I used to run at 15 but have found that the difference between that and using a setting of 9 or 10 is not all that great iron response wise and the lower disc setting really does help give a better response on co-located targets... especially when used in conjunction with high sensitivity settings. It seems to make a difference on the combination ferrous/non-ferrous targets like the rusted back 2 piece buttons. If it picks those up better then you know it's giving better 'see-thru'.
Tom
Hello Dave, Again thanks for the reply. I want to say first that I love my Omega...more so than any detector I have owned before and it has already proved itself to me with the few relic hunts I have taken it on. What I experienced the other day I have not seen before with the Omega..meaning pulltabs ID'ed as pull tabs... until this park. I am curious to what you are referring to as "broad and flat"? When I get a hit I will take the coil and go back and forth across it (not at a fast speed and flat to the ground) to see how the numbers register on each pass. I then will go at it from a 90 degree angle. This is not correct on the Omega?? I can also say that with each pull tab after I have opened up the plug the ID numbers will be the same but as I dig in closer to the tab ,THEN I see them drop down ...usually to a reading about 60. If there is a way to change how I analyze the signal before I dig...then I am all for it. Because they are sure looking like a silver quarter before I dig in close.
Oh and no red clay that I can see at this park. Bill
Oh and no red clay that I can see at this park. Bill
A broad sweep would typically be on the order of 1 1/2 feet. More if you're dealing with deep targets, a foot will usually be enough for surface targets. If there are multiple targets in the sweep, that's okay.
The removal of dirt involved in retrieving a target will change the target ID of a target still in the ground. Metal detectors like dirt which is uniform without discontinuities.
--Dave J.
The removal of dirt involved in retrieving a target will change the target ID of a target still in the ground. Metal detectors like dirt which is uniform without discontinuities.
--Dave J.
is that the filldirt is only a few years old and hasn't had time to settle. I think that is the problem in my yard. I have a real problem if I bury anything over 5", it either disappears or the ID is off. The home is about 4 years old and the ground was turned and worked sodded in front seeded in back... the woods next to the house are totally different.
I bet that is the problem, along with fertilizer etc.
That is the reason I have multiple detectors there is always some site where some detector has a problem and another one doesn't but I bet you can whip this one once you get it figured out. Don't give up on it... figure it out. I think a video of what is happening would be good.
J
I bet that is the problem, along with fertilizer etc.
That is the reason I have multiple detectors there is always some site where some detector has a problem and another one doesn't but I bet you can whip this one once you get it figured out. Don't give up on it... figure it out. I think a video of what is happening would be good.
J
bubbadirect
Member
sekypaleo--I had this happen to me also this past week while metal detecting in Perryville. I also had the pull tabs (and a few screw caps) ring at the 80-99 range, so I was thinking it could be something good. I gave it the 90degree angle test. Sometimes this helped, but most times it didn't. The things that really convinced me about it being junk is when the signal jumped between 3 or more areas, it was junk. (or at least an old rusty nail).
Did you have any of these that jumped around 3 or more categories, or not? If it stayed in the dime or quarter range ONLY, then you have got me thinking now too.
I have had ALL SORTS of items in the ground give me good solid, or what I thought was good solid silver hits, only to end up being junk after all. The 90 degree angle has helped me some, but then I find myself spending 10 minutes going in a circle trying it at 90 degrees, then 180, then 270, then back to my original sweep, just deciding if I should "spend the time" to dig it. Meanwhile, I have just spent 10 minutes going in a crazy circle. UGHH!
USUALLY, if the item jumps 3 or more categories, I have not dug it, as it HAS to be junk...right? Or have I missed more than I should? One thing is certain with the Omega and the 11"DD (or any coil for that matter) is that this machine is VERY SENSITIVE! I was in a field where I was about 70 to 80 yards from an electric fence, and I had to turn the SENS WAY DOWN, which I hated doing! I had to go as low at the 48-50 range to keep the machine stable. There was some power lines about 70 yards away too. I don't think that my machine likes any electricity, except for what the 9V battery gives off to power the unit.
It is amazing to me too, that after you dig off the first 4-6 inches or so, and go back over the hole, that you have a very much accurate ID then. But I find that I am digging alot of holes, when maybe I should be more selective? Some of my past areas digging looking more like that darn gopher on Caddyshack!
Did you have any of these that jumped around 3 or more categories, or not? If it stayed in the dime or quarter range ONLY, then you have got me thinking now too.
I have had ALL SORTS of items in the ground give me good solid, or what I thought was good solid silver hits, only to end up being junk after all. The 90 degree angle has helped me some, but then I find myself spending 10 minutes going in a circle trying it at 90 degrees, then 180, then 270, then back to my original sweep, just deciding if I should "spend the time" to dig it. Meanwhile, I have just spent 10 minutes going in a crazy circle. UGHH!
USUALLY, if the item jumps 3 or more categories, I have not dug it, as it HAS to be junk...right? Or have I missed more than I should? One thing is certain with the Omega and the 11"DD (or any coil for that matter) is that this machine is VERY SENSITIVE! I was in a field where I was about 70 to 80 yards from an electric fence, and I had to turn the SENS WAY DOWN, which I hated doing! I had to go as low at the 48-50 range to keep the machine stable. There was some power lines about 70 yards away too. I don't think that my machine likes any electricity, except for what the 9V battery gives off to power the unit.It is amazing to me too, that after you dig off the first 4-6 inches or so, and go back over the hole, that you have a very much accurate ID then. But I find that I am digging alot of holes, when maybe I should be more selective? Some of my past areas digging looking more like that darn gopher on Caddyshack!