I D FILTER QUESTION

[calabash digger]

I like to run my machines open so I tried a low filter 1 and 0 and 10 today. I went to a iron infested site with the 5 x 10 coil but seems like I was getting a TON of falsing on iron with the filter set so low 0 and 1 that is.. Anyone else noticed this? I had gain on 85 maybe I should have lowered it and it might have helped with the falsing. 3 tone is the progam I was in.

 

[Cal_Cobra]

I noticed when I was using the 3.5x6" NEL/CORS coil that I was getting a fair amount of iron wrap-around with false positives hitting @ 96-97. Once I knew what it was doing, it wasn't an issue, and oddly I didn't notice this phenomena on other coils. My ID filter was set to 2, 3-tone mode and gain @ 90 or so.

 

[Monte]

I like to run my machines open so I tried a low filter 1 and 0 and 10 today.

I also prefer a low Discriminate setting, I almost always set any detector to just barely reject Iron nails, if only using a single tone detector, but with a 2 or 3-Tone model, I set the rejection lower so as to accept Iron nails. The Racer 2 has a Ferrous/Non-Ferrous break point at a numeric '10' VDI, so I have my Racer 2 rejection level set at '3' most of the time. Occasionally I set it lower, but it is mostly at '3'.

I went to a iron infested site with the 5 x 10 coil but seems like I was getting a TON of falsing on iron with the filter set so low 0 and 1 that is.. Anyone else noticed this?

First a comment: If I determine a site to be "iron infested" then, to me, that means there is a lot of Iron of various sizes, shapes and types, from small ferrous bits to nails of various sizes, round and/or square, and other ferrous junk such as bolts or stove parts and all sorts of iron hardware, and the most annoying of all, 'sheet iron' or 'flat iron' in the form of rusty tin.

If the site is really 'infested' then that means an abundance of closely-spaced iron debris, and in those cases of mixed ferrous and non-ferrous trash, closely positioned, I use the 3-Tone mode, Gain at '99' to start and I reduce it if I feel it necessary. I use the smaller size search coils, either the 'OOR' or round 5½" DD, and I work the site in a very slow and methodical manner, remembering to overlap a lot. I like the 5½X10 DD coil on the Racer 2, but only when there is a mild-to-modest amount of iron trash, and when it is mostly just iron nails or similar 'wire iron' such as cut fencing, I prefer to search in the 2-Tone mode with that coil.

So my questions to you are: Did you remember to Ground Balance at the site? Did you use a slow and methodical search coil presentation, and work the search coil 1"-2" off the ground? What type of iron was giving you the most problem? What to you consider 'falsing' to be where you hunted?

I mainly hunt very littered old sites that abound in dense debris, and about the only 'falsing' I get is from rusty tin. It annoys me with the higher TID read-outs that kind of jump around from ± '84' to right around '94' to '96' when swept directly over, but backing the coil off for an 'Edge-Pass Rejection' I can usually get a repeatable Iron TID. Also, with a slow and methodical sweep you can usually hear the low iron grunt just before, just after, or both when you engage most annoying tin.

I had gain on 85 maybe I should have lowered it and it might have helped with the falsing. 3 tone is the progam I was in.

I run my Racer 2 and FORS series models pretty hot and reduce the gain only if I feel it necessary. You could try reducing the Gain and see if that helps.

Also, what TID read-out did you get when you refer to 'falsing?' If it's up in the higher conductivity range, that's usually caused by the effects of the conductive properties and how the iron effects the EMF. Sheet Iron, like rusty tin, will cause that if it was the culprit.

Monte

 

[volpe]

Please explain "edge-pass rejection"

I occasionally get an iron signal, then a null, and again an iron signal when passing over sheet metal.

 

[calabash digger]

yes I ground balanced the machine, it was falsing on nails and bits of iron. I probably just need to spend some more time with the audio of the machine was chasing alot of ghost signals. When I say thick iron I mean thick iron ,hunting relics is my game so civil war and colonial homesites are my main hunting areas. I think I just need to add a little more filter just enough to knock the false off the edge of the square nails ?

 

[Monte]

yes I ground balanced the machine, it was falsing on nails and bits of iron. I probably just need to spend some more time with the audio of the machine was chasing alot of ghost signals.

I usually get 'false signals off of tin and other ferrous sheet metal. Small iron bit or nails and the like usually don't bother me. I know I am going to hear them because I run a low Discriminate setting so they aren't rejected. They will beep, but I also keep the Iron Audio Volume on my Racer 2 and three FORS Relic's set low, at about '2' most of the time. So I hear iron that will disrupt the EMF, and that means it isn't a 'false' signal, it is just an accepted signal and I deal with it using Iron Audio Volume.

To me a 'false signal' is when something causes an audio response when I anticipate it being rejected, or when the audio response is very erratic in both audio and visual TID response. Most of the time that comes from problem iron junk like tin, bottle caps, and similar man-made hunks of ferrous/magnetic material debris in more of a sheet-like form.

When I say thick iron I mean thick iron ,hunting relics is my game so civil war and colonial homesites are my main hunting areas. I think I just need to add a little more filter just enough to knock the false off the edge of the square nails ?

Well, you have an edge on me since you're on the opposite side of the states to hunt Colonial and CWE sites. However, I also spend the bulk of my hunting time in dense iron debris. While I have enjoyed 'traditional' metal detecting since I started in march of '65, and that means essentially Coin Hunting, but even that includes hunting trashy vacant lots, building tear-downs, etc. in larger urban environments, I got hooked on Relic Hunting iron debris fields in old RR ghost towns in may of '69.

Coin Hunting back then produced high quantities of coins, and older places surrendered older coins. Older pioneer and military encampments and town sites dating to the latter 1840's and early 1850's were on my hit list, too, and Relic Hunting had a more interesting draw for me, but detecting equipment was not the best for the uneven and rough terrain, especially with many trash dumps and other iron and non-iron junk scatterings through the '70s and into the early '80s. I still enjoy doing what Gold Nugget Hunting I can, and when in-and-around urban locations I do not shy away from putting in some Coin Hunting time. But since mid-'83, when we got a good start on better performing detectors for Relic Hunting in nasty iron, that is the activity I enjoy the most, and I still mostly hunt old-use places that date from ± 1850 to about the late 1880's when they got their start.

Several of the old gold mining ghost town areas I hunt are from the early-to-mid 1860 era and have more square nails, of various sizes, than round nails. My Relics, CoRe and Racer 2 all handle those sites quite well, and while I, like anyone, can dig some of those nails from time-to-time, I don't find them a serious annoyance and most are easily 'classified' using the audio Tone ID and visual TID responses which qualify them as most probable iron targets.

As I stated, I run a lower Disc. level most of the time using 2-Tone or 3-Tone modes and have the Racer 2 ID Filter/Discriminate level set at '3' to hear nails and a lot of iron, but still deal with some iron and some ground mineral annoyances. There are times, when nails are the primary problem trash, that I might increase the Disc. level to '4' or '5' and that just rejects the nails without too much loss from target masking. Not as good as hearing the nails with a low Iron Audio Volume setting, but better than using a very high rejection setting.

Monte

 

[calabash digger]

maybe I should have explained it better it was calling iron nails non ferrous and high toning on them. I think I can raise id filter to 3,4,5, something and take that false off the iron nail ie high tone. I was running iron vol at 1 as I like to hear it all too ,I love that iron vol feature its nice. I just need some more time with the audio thanks for your jhelp monte.

 

[Monte]

I have enjoyed detecting for over five decades, and will wrap up my 52nd year and start #53 in March. Along the way I have been a very avid enthusiast at not just using a detector, but learning detectors and how to get the best performance out of them. In doing so I have learned, used and taught some of the techniques that have benefitted me, and have named some terms that describe the techniques I use, and have used these terms in instructing folks in club meetings, working at dealer friend's shops, or with customers when I was a detector dealer starting in '77, and in MD Seminars I have been hosting since 1981.

I have used terms like:

ATC .. Audio Target Classification or methods to 'classify' some targets as probably ferrous-based or non-ferrous, and also other functions. Two of the techniques mentioned are 'Quick-Out' and 'EPR.'

'Quick-Out' .. I started using this technique in '83. It is a technique that works sometimes with a motion-based Discriminator, especially a slower-sweep type using a 2-filter or 3-filter circuitry, that allows you to make a very brisk [size=small]('Quick')[/size], but short-length sweep across a located questionable target, that might degrade or reject the audio signal to 'classify' [size=small](knock 'Out')[/size] the target as probably being a ferrous-based piece of junk. An example would be a rusty, crimp-on bottle cap. It can even help a TID model provide a more correct visual TID of ferrous trash. Sometimes either the detector, the coil used, or the problem trash ferrous junk might not kick-out using this technique, so I then employ 'EPR.'

'EPR' .. This is a technique that I was using back in the early days of conventional TR detectors in '71, before Discriminators were popular, to help 'classify' probable iron targets. It worked great with the good TR's I used, and still do with my Compass Coin Hustler and Yukon 99B, and can work with other Discriminators. It is especially useful with out modern, motion-based Discriminate models that often have more trouble with some iron, nickel, steel and other challenging-shaped magnetic metal targets, especially things like crimp-on bottle caps.

'EPR', short for 'Edge-Pass Rejection', is a technique where you isolate or pinpoint the location of a questionable target that gives you a good or iffy audio response and, if you have visual TID, a jumpy or unsteady read-out. Then, you continue to make a side-to-side sweep across the target. Not a long-length sweep, just enough for the search coil to just completely cross the located target.

While doing so you work the search coil back towards you so that the targeted location is swept across with the front 'edge' of the search coil. This is not always going to work the same from detector-to-detector or from one type and size search coil to a different one due to the differences in the shape and effect of the EMF, the coil's internal positioning, and how the detector's circuitry processes the received signal.

Usually, the 'EPR' technique works well with a Concentric search coil when the target is about ½" to 1" inside the coil's diameter towards the center from the outer 'edge' of the coil. NOT right at the very 'edge' of the coil but close to it. Most often, a Double-D coil might not display a proper 'EPR' until the targeted spot is near the outer edge to maybe 1" or so away from the outer coil's edge.

What does it do? Many problem iron-based targets cause us problems because man has shaped them into a more conductive shape. Again, a rusty or even unused bottle cap is a prime example. While many early conventional TR-Discriminators could reject a bottle cap, the modern motion-based units we use today might have problems with those and some other iron-type targets. Both coil types, but especially DD's seem to be challenged by them and 'false signal' a lot. We sweep over a bottle cap or other annoying targets and get a reasonably good audio response and maybe a so-so good TID. Reasonably good, but kind of a questionable audio or somewhat inconsistent TID that hints to a potential ferrous based piece of junk.

Time to use 'Quick-Out' and, if that doesn't work or to add an extra measure of classification, we employ the 'EPR' technique. If the target is a non-ferrous metal coin, such as a US 1¢, 5¢ 25¢ or other coin, you will continue to get a good repeatable audio response and an OK TID as you draw the coil back towards you while just sweeping across the targeted spot until you get to the 'edge' area and lose detection of the coin.

If the target is a bottle cap, piece of rusty tin, an iron bolt or washer, etc., then when you find the functional 'edge' area of your detector/coil doing an 'Edge-Pass' you will get an obvious 'Rejection' of the iron target. If your Discrimination is low for more iron targets, then more will be heard with a low tone [size=small](if your detector is working in a 2-Tone, 3-Tone or other multi-tone function that can indicate iron with a lower tone)[/size] and will also display a proper 'Iron ID' range visual response. I Relic Hunt most of the time, but use this technique a lot for both Relic Hunting and Coin Hunting needs.

Power Balance .. This is a technique I have used since about 1980, teach in seminars since '81, and have especially relied on since mid-'83 using many [size=small](not all)[/size] motion-based detectors to adjust for a most efficient working Ground Balance while in the silent-search Discriminate mode. It has been most useful with most Tesoro Discriminators, many brands that used or copied the Tesoro type circuitry, or others that had a tie-in between the motion-based Disc. mode GB and the Threshold-based All Metal mode GB adjustment.

Please explain "edge-pass rejection"

I occasionally get an iron signal, then a null, and again an iron signal when passing over sheet metal.

If you hear an Iron Audio signal, then a NULL, and then the iron signal again after passing the target, and it is sheet iron, that is not totally uncommon depending upon the detector model used, the settings used and the search coil used.

Iron has a different effect on the EMF than a same-size and shape piece of non-ferrous metal and the coils used and settings can create different results. When Relic Hunting sites with a lot of rusty tin type trash, I prefer to use the Racer 2, CoRe and Relic in their 3-Tone Discriminate mode instead of any 2-Tone mode. This provide me a little better ability to hear a low-Tone before, after or both when I encounter challenging sheet metal, and remember, I hunt with a high Gain setting and a low Disc. setting that lets me hear ferrous junk in an area. When it gets bad like that, I also tend to use the Racer 2 or Relic because I can reduce the Iron Audio Volume.

Sorry for the delayed response but we've been dealing with bitter coil [size=small](it was -19° F last night)[/size] and a lot of snow. I just partially shoveled my driveway, but it tired this old phart out and I need a breather to finish. This was a 4" dump and I already shoveled 5" to 6" total earlier this afternoon in two trips outside.

Enjoy the Racer 2 as it is one of the best multi-purpose detectors out there today.

Monte

 

[calabash digger]

I do use the technique of backing the coil off the suspect target till it gets to the edge and it shows itself as iron. I will say this I love the seperation of the racer but the audio is not as nuanced as my deus. What I mean is this I hunt in full tones with deus which I think is 39 tones it works on a sliding scale lower conductivity lower the tone ,the higher conductivity the higher the tone. so you take a penny,dime,quarters,silver dime,silver quarters, etc the deus will vary tonal wise on each of those targets and not just dump them in the high tone bin. Same with bottle caps alot of times the tone alone will give them away and iron will most the time be giving away too. I know for relics you just need a machine that tells you ferrous or non ferrous but its really nice to have that much nuance in the tones.

 

[volpe]

Thank you Monte and Calabash Digger for your responses. Both are very helpful. I've been using my racer 2 in two tone, and then going to deep mode to help identify a target, I'll be using three tone as explained by Monte. The R2 is the first detector I've had a chance to use. Some time ago I was in electronic intelligence intercept and signal analysis and metal detectors work in many ways, the same as radar, radar is not just the echo reflection of a target, it interrogates, even probes. However, depending on analogies is misleading, I have a lot to learn and really enjoy doing so. EPR is an example, I thought the edge you were referring to was the edge, side edge, as it approached and passed over the target, using the front edge is an eye opener. I have notice that the R2 "sees" a target just in front of the coil but it did not occur to me what was happening.
I wish the R2 reported in a sliding scale of tones, however, it gives me much more info than I, as yet, am able to use. Keeping a log, depth, settings, locations etc. helps but using what I have found, and practicing and experimenting, with the R2 is not only useful but fun as well.
Reading these forums is akin to going to school and using the info in the field, experience, is a great help. You guys are assets.

 

[Monte]

maybe I should have explained it better it was calling iron nails non ferrous and high toning on them. I think I can raise id filter to 3,4,5, something and take that false off the iron nail ie high tone. I was running iron vol at 1 as I like to hear it all too ,I love that iron vol feature its nice. I just need some more time with the audio thanks for your jhelp monte.

Usually with an ID Filter setting of '3' on the Racer 2, you will still hear most iron nails. Also, because most iron nails have such a low numeric TID in the Iron range, all you will hear is a Low-Tone Iron Audio response, not a High-Tone response.

However, other settings used, the coil used, and the presence of any other nearby targets, ferrous or non-ferrous, you might get a mixed response. Also, a Nail is not just a Nail with only one normal straight shape. Some nails are thicker, some might have a pronounced bend in them, and we can't forget the head of the nail. The head of the nail is sometimes a rounder shape, and if the nail is laying horizontal in the ground and to the search coil, the head of the nail is at a 90° angle. There are times when we can get an errant response [size=small](you could say a 'false' response)[/size] because it is an iron object with a challenging configuration that might cause an errant High-Tone due to it's shape.

I also enjoy the Iron Audio Volume control on my Racer 2 and Relic which is why they are in my regular-carry detector battery.
.
Monte