Nulling problem?

[Mentez]

Hi All

I took the gt out today on a series of fields, quite clay ground, lots of fossils, fairly normal soil really, a little coke, iron trash. The GT was fine until about 4 hours in, when it started to null all the time there was any change in the ground in terms of ground height. It had rained about an hour in and was fine until I moved from a harrowed field to a stubble field I am a bit concerned to say the least.....! If the coil was bumped on the ground it nulled. I was using the detector in the following settings -

Disc 2
Threshold on
No Notch
Sens, Auto (it made no difference in auto or manual)
Iron mask on


It was pretty worrying seeing as the detector is two weeks old and this was it's second full outing. I'm hoping it's something simple like the coil wire being too jumbled or a little dirt in the coil cover?

Any ideas?....Critter, I'm looking at you

Also, I spoke to another GT user and asked if he'd show me what settings he used on this sort of field, it was as if I was asking to borrow his wallet, take his car, sleep in his bed, and seduce his wife!! Anyway, he told me that he gets a maximum depth on "grots" - knackered roman coins about 1cm across - of about 5 inches!!!! I looked at his settings and noticed that he had it in auto, he told me he never takes it out of auto. This can't be true....5 inches is pathetic, it's about what my old treasure ace used to get. I found a piece of bronze at about 11 inches today that was an inch across so I started to think he was misguiding me. He then walked off swinging his detector coil at 8 inches above the ground in a U shape at 19845674843 miles an hour,,,,,,,,,,,puzzle solved

 

[jbow]

Mine always nulls a lot but it still hits the goodies. My problem in mineralized ground and lots of small iron. I usually run it with the sens between 1:00 and 2:00. The only way I ever get any sort of stable threshold is to run in AUTO.
I know some experienced Sovereign users who relic hunt and always run in "silent search" so as not to be annoyed or bothered by the constant nulling.

FWIW, I see that sort of swing a lot whenever I go to the beach, it is amazing isn't it? 8" off the ground in the middle 12" at each end and moving fast... but they clean out the shallow trash for us so.... I guess it is OK!

I find that the Sovereign, even if it is nulling will (like I said) still signal a good target if you have a good swing and aren't flying along... neither do you have to crawl along. If you are going just a little too fast it will beep past the spot where the target actually is but if you're going too fast and there is something heavily masked, like between two pieces of iron, you may miss it. Then again there are always those flases that show up inbetween two pieces of iron... those drive me nuts. I usualll know what it is but I cannot stand it, I always think, "this time it is really something"... it never is though.

I wouldn't worry too much about the null as long as you aren't flying along and as long as your sensitivity isn't too high. Too high can be as bad as too low if your swing does not match the sens. A lower sens is more forgiving to a bit faster swing. Higher sens can be like "high beams" in fog if you don't slow down because it is processing more ground than need be. There is, I think, a blanace between high sens and swing speed and a point where turning it higher is detrimental to your hunt. In neutral soil like a quartz sand beach I can run mine really high and mive along nicely but in red clay, iron bits and ore... forget it. I cannot run it above 12:00 unless I really slow down but I think that setting the sens a little lower and swinging a little faster works just as well... in any case I think that the swing speed is intimately tied to the sensitivity setting... and in AM you can swing quite a bit faster without missing targets.

Mine also falses if I bump stuff...

J

 

[Mentez]

Many thanks Julien

It's put my mind at rest. I've thought about what you've said and it makes perfect sense. I reckon the ground was pretty mineralized and had coke and iron dotted about. I think the machine just nulled it's way out of trouble.

Well, let's see what tomorrow brings, I'm off to an Iron age/Roman site which has decent crop-marks on ariel photo's so it'll be mineralized again. I am hoping that the GT still accepts good signals while it's nulling!

Fingers crossed.

Thanks for taking the time to help me out Julien.

 

[deanosaur1972]

If the coil was bumped on the ground it nulled.

I will leave that to the experts but will say that in my opinion any metal detector that is bumped will null or false.

He then walked off swinging his detector coil at 8 inches above the ground in a U shape at 19845674843 miles an hour,,,,,,,,,,,puzzle solved

Yep that's consistent with just about all the metal detectorists in my area........... it really is unbelievable to see isn't it.......... to the point where it makes me dizzy to watch!!


Right I am off to find a gold ring for someone.......... with not much chance of finding it !!!

 

[GraveDiggerMax-VaBch-Va]

we have a guy here like this:

FWIW, I see that sort of swing a lot whenever I go to the beach, it is amazing isn't it? 8" off the ground in the middle 12" at each end and moving fast... but they clean out the shallow trash for us so.... I guess it is OK!

He does not find as much as most of us.............like small things and such, but what he does find are usually knockout big gold items...........big rings, cell phones, watches..........big gold bangels....and lots of glasses.
truely amazing what he finds

 

[kered]

Sound to me you passed from a normal area to a heavily used area at one time, maybe the place of an old building that was once there or something to the like.
From grots i take it your in Uk
Slowing down once you get to these areas usually produces the goods, also a smaller coil to get between the iron(nulls)may help, turning down the sensibility a bit also helps, even at 1 or 2 oclock you'd be suprised at the depth

 

[Critterhunter]

If you are nulling it's either:

1) A lot of iron in the ground.
2) Hot rocks
3) Too high of sensitivity.
4) Too fast of swing rate. Slow it down and often the nulling goes away.
5)Not keeping the coil level. Level doesn't mean touching the ground. I try to skim the surface without touching anything but the very tips of the grass. Momentary contact with the ground or crop stubble can cause any machine to null or false. I never was a "scrubber" because I found the falsing it causes any machine by continuously bumping it across the top of the ground erased any slight depth advantage it might have.

There are a few sites where even a Minelab has trouble. In those cases I find often Auto will smooth out the threshold, but usually lowering sensitivity in manual to like 2 or 3PM will take care of it. If you have to go lower than 3PM then I'd just go ahead and run in Auto because it normally gets about the depth of 3 to 3:330 PM on the dial from my testing. Auto will be more stable than say a 3:30 PM manual setting yet get about the same depth, so I wouldn't see much point running in manual once you go that low.

Next time you are at a site like this flip over to All Metal Track for about 3 minutes and then flip it over to fixed. Now sweep around and see if you are hearing a lot of targets. If you are then that tells you it's just a bunch of iron around and the machine is doing what it's meant to do- null out the iron. Flip back over to track and check the same area again. Are most of those "targets" gone now? Then that tells you it probably isn't iron but rather hot rocks or mineral content in the soil. I'd still use discriminate but either move slower or go to a smaller coil like he said to see through the iron better and give you less "null time".

If you are really getting distracted by the nulling then turn OFF iron mask. If the machine is still driving you to the point of distraction then flip over to silent search. Both of these features will take an unhuntable site for any machine and make it a very easy hunt for the Sovereign when you are in the worst of the worst. They both also help when you can't keep the coil even with the ground such as in crop field stubble or uneven ground.

In particular if you are in the "highest stable sensitivity camp- high as possible" then you for sure need to move the coil ultra slow or it's going to null on you. Even if you are in my camp and often run much lower like around 2PM or so too fast of a sweep speed in high minerals or heavy iron can cause falsing or nulling. I've got a spot like that which is loaded with tiny gravel and thus hot rocks, causing nulls or false coin hits. For that reason I'll usually run in Auto in this spot or say when hunting old foot trails. What I've found is if the soil is heavy clay and packed from foot traffic the machine runs so much better in Auto, in particular if there are any kinds of rocks or gravel in the soil. In auto a silver coin at 7 or 8" is no problem, and how much deep digging do you want to do in packed clay/rocky soil anyway? Besides that, most targets in this kind of soil won't be deep. Sounds like your issue is either with iron, hot rocks, or very heavy minerals, though.

 

[Mentez]

Thanks Critter

Day two on the site, and much better. I think that a combination of the stubble, mineralised soil (it's got loads of small rocks, pebbles, fossils in it), and complete operator malfunction, caused so much instability yesterday.

Today I tried backing off the sensitivity and slowing down the sweep speed but I ended up at 4 o'clock on the sens and travelling like ironside with a puncture! In the end I set the sens to Auto and tried not to bash the stubble about too much. Even in the appalling condtions (and even by UK standards this site was poor) the GT gave me bags of confidence. A seed tag came up from about a foot and my find of the day - a Viking/Saxon Mount - came up from a respectable 8 inches (Don't forget that the stubble put at least a 5 inch gap between the coil and the ground).

I have to say that I was most impressed with the GT and the way it handled the conditions. The find of the day belonged to the luckiest club member going...and his lobo supertrac! It was perfect conditions for a lobo today.....I'll get him next time

 

[jbow]

Well... you cannot argue with the facts can you? Good finds validate any style of hunting.

It sort of makes sense doesn't it? Move fast and get the bigger items... huh... !!??!

J

 

[synthnut]

When beach hunting, the more ground you cover , the more good finds you will have ......In dry sand , you can run high sensitivity without issue on most beaches ... Items that are lost , are usually lost the day before or not much earlier ..They reallly aren't that deep yet .......You can bet that if it's a frequented beach , that there are other vultures around to get on that beach before YOU do to get the goods !!!....That's the way it is around here on NY beaches .... You snooze, you loose ....I'm not saying run your coil a foot above the ground, but don't be so concerned with being right on top of the sand getting sand in between your coil and cover ..... ANY machine will ring out like crazy and get good depth in dry sand .... Jim

 

[Critterhunter]

Sounds like you are off to a good start with your Sovereign.

As for beaches, on the great lakes where I hunt there is a ton of trash in the dry sand at some locations. I go slow and grid and try to scoop out every signal regardless of how junky it sounds. At one site it was obvious that somebody had dug all the nickle signals but every other coin along with a ton of trash was still present. There are some gold rings that can read as high as 180 on the meter, so I scoop any penny or dime signals regardless if I think it's yet another zinc penny. I have no problem with scooping any and all signals on the dry beach. It's only when land hunting for rings that I get particular about how good of a signal it has to be along with it being below penny on the VDI. Not enough rings above a zinc (173) signal to make it worth digging those targets on land in a heavy trash area. I'll concentrate on any target below 173 on the dial and also as always run the notch to eliminate most of the tabs if the place is loaded with them. If there are many bits of foil and small can shards laying around I'll raise the discrimination to about 90 on the VDI once I come acrossed one of those targets. That greatly quiets the machine down when foil or bits of aluminum is everywhere having been hit by a lawn mower or something. Rings start at about 75 on the VDI and go up from there. As somebody else said I love to dig any lower number that gives a steady ID and audio when swept from any direction. Even if they turn out not to be rings often these are good targets of some interest.

 

[Mentez]

It's really interesting reading how most of you guys detect. Some of it I'm totally unfamiliar with ie beach detecting, but the rest of it seems so weird. Like most "relic" hunters over there head for schools/parks/battlefields. Well here you just go for almost any farmland and you are 99% certain to get coins/jewelry/votive offerings/musket balls/buttons and loads of other ancient metal work like horse pendants, spurs, arrowheads, daggers etc etc etc

When I read a lot of the posts on here I get the impression that most of your farmland is really quiet in terms of signals? No-one seems to just go out randomly to any given field in the middle of no-where? It's taking a bit of getting used to as you all seem to target your hunting a little differently to over here. In my experience, we dig any half decent signal as just about any location will contain good targets. Come to think of it I think my "modern" (by this I mean in the past 100 years) coin find rate is far outweighed by coins which are much earlier than this. And those old coins really sing when a detector goes over them! Most Medieval/Viking/Saxon/Roman jewelry is bronze/silver/gold and also gives a good signal. What our main problem is, is the abundance of iron in the form of nails/plough shards/wire/coke/and varying bits of ferrous junk. At least on my sites for every good signal there will be at least 30 bad ones sometimes many many more.
For those reasons, the GT is turning out to be more of a superb machine than a lot of guys over in the USA might experience due to it's fantastic discrimination. I've never had a detector that I've had as much confidence in and "good" signals actually mean good targets. No longer do I have to spend time digging up large bits of tractors/ploughs/bolts because the signal given is "dig me dig me dig me". The GT may say "dig me" once, but then it will have a second look and tell you to move on. Honestly in all my 20 years of detecting I've never come across a machine which has suited what I do so well. And the beauty is that it is just so simple. Bad signal - don't dig, Good signal - Dig....simple. I no longer have to be a nail magnet. I thought my x-terra was good, but this thing is awesome.


The only comparable machine over here is one I don't think you can buy over there, I think it's illegal? It's called the XP Goldmaxx power, you've probably never seen one? Well a couple of club members have them and, apart from the etrac, are the only machines that get close to the GT for discrimination and depth.


And I have to say, all of the comments and posts you all make are just so interesting and helpful, so thanks to everyone, even the smallest comment can be so useful.

 

[Critterhunter]

We've got our share of iron depending on the site. Most people in the US head for beaches or sporting fields/play grounds when targeting rings, or head for old parks or houses when going after old coins. As for "relic" hunting many also enjoy doing that at older sites such as houses, parks, or farm fields. In particular there are a lot of Civil War relic hunters who do that when they live in a state with that kind of history.

As far as hunting open farm fields go...Yes, there are some in the US who specialize in that kind of hunting. I've done some of that and often there is a bunch of iron in the fields or at the very least anywhere near the barn or house. A lot of people walked behind plows back in the day and were constantly pulling something out of their pocket to wipe the sweat off their face. One killer spot in old farm fields is where one large (usually oak) tree was left in the middle of the field to provide shade during breaks from the farm work. Lacking that any large trees near the edges of the field were often sat under to get out of the sun.

Some of the worst iron infested spots I've ever hunted was right near old barns. Often they'd work on farm equipment around the barn and as a result all sorts of iron junk can be found there. Our older parks can be full of iron as well from days gone by. Older non-farm houses some times don't have any iron present in their yards, while others are loaded with it.

Mainly I think the difference between where you live versus the US is that you've got much more potential for "any old field" to have seen some long history and so have more potential to hold old coins or relics. Depending on use some of our farm fields aren't old enough to really hold much. Hit the right one though and it's full of targets. Primarily most people who detect in the US probably live near major cities and so don't have access to close farm fields to hunt. I know for me I have to drive about 20 or 30 miles away from the city before I start to see any farm fields that would be worth hunting. Even then there's still a matter of gaining permission and that's not always easy. Further still these fields often have crops in them from like April to about November so you've got to hit them after they are harvested in the fall but before they are planted again in the spring. That usually means very wet/muddy conditions were I live. I do a lot of goose hunting in farm fields over the winter and when you walk with 10 pounds of mud on your boots you get tired very quick.

As an interesting side note, one old farm field I goose hunt in has a large tree in the center like I mentioned above. Around this tree in the harvested crop field I often spy pottery shards and old red bricks. That tells me there might have been an even older house site in this field before the other old farm house was built. I keep meaning to ask permission to metal detect that place but often find myself hunting game rather than coins at that time of year.

PS- My favorite type of metal detecting (besides virgin ground old house yards) is hunting "in the middle of nowhere" in the woods. I try to target ridge spines as well as rivers, ponds, or other water sources. Any place that might have attracted people (water) or created a bottle neck (ridge spines) that they needed to use to get from point A to point B. Even a slight rise in lower ground could offer dry camping conditions when ground only a foot or two lower around it was soaking wet.

Often I'll go several hunts before I see any kind of coin or much in the way in any signals for that matter. But I also often come across areas where human activity has left lots of iron (usually nails) or other trash. When I start picking up a lot of iron that's how I know the area has potential. Some of these spots are out in the middle of no where and don't even have the usual trappings of water or land barriers that would raise the potential for having seen some activity in years gone by. I'll sit there and wonder "why the heck did somebody find this spot useful in the past?" You just never know. Some of my best looking sites turned out to be lacking much of anything in the way of signals, yet they were so remote or hard to get to that I'm reasonably sure I was the first to hunt them. Then other spots that you were just mainly walking through to get to other parts of the woods turn out to be loaded with signals. Always amazes me and peaks my curiosity as to why and when people used places like that.

I mainly will take my dog for hikes in the woods to scout out new areas without a metal detector. I look for older trees with carvings on them, depressions in the ground that might have been root cellars or such, pottery shards, old bricks, rocks piled up in one spot (often they cleared nearby fields for crops and piled the rocks in one spot near the edge, old broken glass (blue glass or heavy/blown glass), faint outlines of old roads or trails, or even a patch of trees that look younger than the surrounding ones and so might have been the site of a cabin or house back in the day. I've even found old "roads" because you could see the perfect border line of older trees that lined the sides of them, while much younger trees have since grown up in the middle of those once used travel ways. I get as much satisfaction at finding clues to prior human activity in an area than I do digging an old silver coin. It's all part of the same discovery process and unveiling history.

 

[otlew]

we have a guy here like this:

FWIW, I see that sort of swing a lot whenever I go to the beach, it is amazing isn't it? 8" off the ground in the middle 12" at each end and moving fast... but they clean out the shallow trash for us so.... I guess it is OK!

He does not find as much as most of us.............like small things and such, but what he does find are usually knockout big gold items...........big rings, cell phones, watches..........big gold bangels....and lots of glasses.
truely amazing what he finds

I was hunting the beach last evening and witnessed what you are describing above, but they were doing a bit better....I would guess 2" off the ground and 4" off at end of the their swings walking at a pretty good clip.

I however I may be going too slow with too little distance on the swing from side to side. I do my best to keep it level and about 1/2" off the surface. In three hours I didn't cover much ground as a result.

I have made a total of about 4 hunts = 20 hours with my Sovereign and I am still trying to learn and the remember the sounds, get the swing speed and sensitivity sorted. I do have faith in the GT, just need to get past the initial learning. Just a few coins so far.

Since the topic of this thread is nulling, I have a question. After nulling on ferrous metal, how long should it take for the threshold sound to return?

I have been raising the coil about 18" above the ground or passing it by my stainless scoop and then the threshold sound will return, I know it should return on its on, but it seems to take too long, however I suspect that my Sovereign is behaving to design. So if someone could confirm this...

I am running Auto Sens(for now), 0 notch, 0 Disc, volume max, iron mask on, and threshold just audible. With those settings I found all the tab rings you could ever want to dig, some foil, and one crusty Zlincoln. I'll say this, I know what the small tab rings sound like now.

 

[Montauk3]

we have a guy here like this:

FWIW, I see that sort of swing a lot whenever I go to the beach, it is amazing isn't it? 8" off the ground in the middle 12" at each end and moving fast... but they clean out the shallow trash for us so.... I guess it is OK!

He does not find as much as most of us.............like small things and such, but what he does find are usually knockout big gold items...........big rings, cell phones, watches..........big gold bangels....and lots of glasses.
truely amazing what he finds

I was hunting the beach last evening and witnessed what you are describing above, but they were doing a bit better....I would guess 2" off the ground and 4" off at end of the their swings walking at a pretty good clip.

I however I may be going too slow with too little distance on the swing from side to side. I do my best to keep it level and about 1/2" off the surface. In three hours I didn't cover much ground as a result.

I have made a total of about 4 hunts = 20 hours with my Sovereign and I am still trying to learn and the remember the sounds, get the swing speed and sensitivity sorted. I do have faith in the GT, just need to get past the initial learning. Just a few coins so far.

Since the topic of this thread is nulling, I have a question. After nulling on ferrous metal, how long should it take for the threshold sound to return?

I have been raising the coil about 18" above the ground or passing it by my stainless scoop and then the threshold sound will return, I know it should return on its on, but it seems to take too long, however I suspect that my Sovereign is behaving to design. So if someone could confirm this...

I am running Auto Sens(for now), 0 notch, 0 Disc, volume max, iron mask on, and threshold just audible. With those settings I found all the tab rings you could ever want to dig, some foil, and one crusty Zlincoln. I'll say this, I know what the small tab rings sound like now.

A coin embedded in my sandal front will return the machine to threshold after passing the coil over it.
I used to pass the coil over the scoop, but the sandal coin is better for me.

Hope this helps.

 

[otlew]

we have a guy here like this:

FWIW, I see that sort of swing a lot whenever I go to the beach, it is amazing isn't it? 8" off the ground in the middle 12" at each end and moving fast... but they clean out the shallow trash for us so.... I guess it is OK!

He does not find as much as most of us.............like small things and such, but what he does find are usually knockout big gold items...........big rings, cell phones, watches..........big gold bangels....and lots of glasses.
truely amazing what he finds

I was hunting the beach last evening and witnessed what you are describing above, but they were doing a bit better....I would guess 2" off the ground and 4" off at end of the their swings walking at a pretty good clip.

I however I may be going too slow with too little distance on the swing from side to side. I do my best to keep it level and about 1/2" off the surface. In three hours I didn't cover much ground as a result.

I have made a total of about 4 hunts = 20 hours with my Sovereign and I am still trying to learn and the remember the sounds, get the swing speed and sensitivity sorted. I do have faith in the GT, just need to get past the initial learning. Just a few coins so far.

Since the topic of this thread is nulling, I have a question. After nulling on ferrous metal, how long should it take for the threshold sound to return?

I have been raising the coil about 18" above the ground or passing it by my stainless scoop and then the threshold sound will return, I know it should return on its on, but it seems to take too long, however I suspect that my Sovereign is behaving to design. So if someone could confirm this...

I am running Auto Sens(for now), 0 notch, 0 Disc, volume max, iron mask on, and threshold just audible. With those settings I found all the tab rings you could ever want to dig, some foil, and one crusty Zlincoln. I'll say this, I know what the small tab rings sound like now.

A coin embedded in my sandal front will return the machine to threshold after passing the coil over it.
I used to pass the coil over the scoop, but the sandal coin is better for me.

Hope this helps.

Great method. I shall use it in some form or fashion.

 

[kered]

you could also just flip the all metal/disc switch

 

[otlew]

you could also just flip the all metal/disc switch

That should be very easy to do, it might get a bit tiresome when you're having a lot of nulling especially on the beach and you keep your cover closed on your pouch. I may just glue the coin to a wading boot, that would seem to be the fastest when nulling is happening repeatedly.

 

[Buried Crap NJ]

you could also just flip the all metal/disc switch

That should be very easy to do, it might get a bit tiresome when you're having a lot of nulling especially on the beach and you keep your cover closed on your pouch. I may just glue the coin to a wading boot, that would seem to be the fastest when nulling is happening repeatedly.

I use to have nickel on the glued to the toe for older machines. But once I got my first Minelab that went out to lunch. The BBS/FBS minelabs will target that coin every swing. That's why as you narrow your swing when pinpointing the machine can better identify the target. Not a good idea any longer.

 

[otlew]

you could also just flip the all metal/disc switch

That should be very easy to do, it might get a bit tiresome when you're having a lot of nulling especially on the beach and you keep your cover closed on your pouch. I may just glue the coin to a wading boot, that would seem to be the fastest when nulling is happening repeatedly.

I use to have nickel on the glued to the toe for older machines. But once I got my first Minelab that went out to lunch. The BBS/FBS minelabs will target that coin every swing. That's why as you narrow your swing when pinpointing the machine can better identify the target. Not a good idea any longer.

I understand, well I can live with it nulling, so I think I will just wait for the threshold to come back and keep swinging, or flip the switch as suggested.