greasecarguy said:
Iron will sound good sometimes, crown caps and screw on bottle tops too.Aaron
Iron: Rusty nails can sound good in both Ferrous and Conductive, step 1 turn 90 degrees and sweep the target again, did the tone go low? Did the target seem to shift position on you e.g. you thought you had it pinpointed and now it seems off to one side? If yes its likely a rusty nail. There is rarely a reason to dig a rusty nail in my opinion, the Explorer gives you ample information to avoid them. An exception would be a bent nail which can sound high from two directions. Pay attention not just to target tone but the target behavior, e.g. the cursor bounce patterns on the smart find screen. Rusty nails behavior is as consistent as the sun rising. The bounce pattern when falsing is from the top left corner of the screen, to the far right edge of the screen, cursor half off the edge, in the silver half dollar area. About the only thing that ID's in the silver half dollar range is a silver half dollar and you won't find one of those bouncing to the top left corner. Maybe if its fused to big rusty iron, even then the silver is probably going to keep the bounce to the right of the top left corner. So if you have a target bouncing left and right via this rusty nail bounce pattern its a very good bet the target is rusty iron. I will also note that you must have your coil centered over the target, if you sweep a rusty nail with just the front or side edge of your coil its likely to false high but once centered over the target it will very often go low.
Crown Caps: Again their behavior is very consistent. As you sweep over a rusty crowncap, firsdt you get that high pitch tone but as your coil comes off the target you will hear a distinct Pop in your headphones, that is the tip off for rusty crowncaps. About the only crowncap that will fool me is when the rim of the crowncap is rusted completely away leaving just a flat rusty disk. Rusty crowncaps also like to hang out on the lower half of the rusty crowncap discrimination area, if you have a target that ID's towards the top or even higher, and isn't popping like a crowncap or just sounds too sweet to be a crowncap, discriminate the crowncap out and sweep again, if the cursor then goes even higher you have the rare but not that rare silver coin hiding under a rusty crowncap. I have dug barber halfs this way. Finally, I personally find rusty crowncaps very annoying if there are a lot of them in a given site so I will discriminate them out e.g. my screen will be wide open except for the factory rustry crowncap discriminiation turned on.
Screw caps are more challenging. They sound different than a coin to me, aluminum has it's sound just like silver but its subtle. If I had not dug one in a while I'd have to dig 2-3 to retrain my ears. Aluminum screw caps also ID around the coin area, but are generally a bit lower than silver, maybe indian cent height over near the right edge of the screen. I am usually suspicious of them before I dig them e.g. I can call my shot on a screwcap with fairly good accuracy. I'll still dig to confirm and if I dig a few I'll begin skipping those targets once the tone is fresh in my ears. A screwcap smashed flat is my most hated type of screwcap.
greasecarguy said:
So I would occasionally use just a bit of discrim....maybe 31 or 30 so I don't have to hear everything.
Nothing wrong with that while you are 'transitioning' into all metal. I have advocated that if you want to learn to hunt in all metal that you do so gradually, otherwise all the rusty nail signals will drive you batty. I used to get a serious headache when first trying to hunt in all metal from listening to all the low iron tones. So I would hunt in all metal for maybe an hour, then disc them out and enjoy some peace and quiet for a while. In time what happens is that your brain learns to ignore the low iron tones, they become part of the threshold tone fading into the background. I can hunt all day in all metal today quite comfortably and don't really notice the low iron tones but this was not always the case.
greasecarguy said:
I have been hesitant about adding more discrim as I want max depth however, I was reading an excerpt from Andy's book written by Bryce. Very interesting that he states he has seen no reduction in depth at IM 22
It is not depth that you seek (makes with the Jedi mind control) with all metal, it is target separation. I'll say this again, its not about depth. This one is tricky so stick with me. First lets settle this depth thing. The Explorer transmists at 100% power at all times, thus returning the best possible signal on deep targets at all times, no matter what settings you are running. Are you with me? So the Explorer transmits at 100%, the best possible target signal is returned to the control box. Your settings then slice, dice, and filter that returned signal. So here's my return signal on a target, its got some noise in it lets slice that off with the best noise cancel channel. It's got some ground signal in it, the Explorer manages that for you removing most of that. If you have some discrimination set this removes various chunks of the return signal, nails, crowncaps, whatever you have told the machine to discriminate out. Now we get to sensitivity. Lets say this is a deep target, the sensitivity setting is an accept/reject setting. Lets say I have my sensitivity set to 26. This tells the machine to accept the portion of the return signal up to the sensitivity strength of 26, and reject anything in the 27-32 range. This is confirmed with Minelab by the way and I'm about to drop a bomb shell so geat ready. There are camps of thought out there that recommend cranking the gain to 10, and lowering the sensitivity. Minelab confirms that cranking the gain to 10 will not help one bit when you have already eliminated a deep target by turning your sensitivity too low e.g. your sensitivity setting is processed first, then gain is applied to whats left of the signal.
Now enough of theory lets get back to target separaton. Rusty nails can pollute a sizeable area around themselves as they cast a rusty nail signal out several inches along their lenth. When you have iron descriminated out Explorers null on iron and tend to latch onto to this iron signal and not want to let go. This is more true of Explorers and Explorer II's than later Explorers but is true for all of them to varying degrees. In all metal there are no nulls (there is one exception) and Explorers tend to let go of nails and latch onto nearby good targets hiding in the shadow of nails. So it is target separation that you seek, not depth with all metal. The same is true for shallow modern trash, a shallow crowncap or screwcap, clad penny, whatever can pollute quite an area that will null, but when running in all metal with no sticky nulls in the way the Explorer is really good about latching onto nearby good signals hiding in that polluted area. The all metal null exception I mentioned is this, the machine is not supposed to null in all metal right, hold that thought. Here's the scenerio, two rusty nails at 9 and 3 oclock about a foot apart, pointing at each other casting that iron signal out into the middle ground. Inbetween the two is a null, oddly the machine goes silent, like its confused and doesn't know what to do, if so there is likely a good target inbetween the two nails where the Explorer appears to null. I have dug silver quarters in this situation.
greasecarguy said:
Today I went to a field where they play ball...not too old, but I have been there before and found some deep wheat's but no silver. Today was different in that with this new setting structure, I made a lot more progress and covered much more ground than usual.
Ah site conditions. Settings and your strategy for hunting a site should be governed by the site conditions. I have hunted sites polluted with 200 years worth of rusty nails and took 2 hours to cover an area the size of a living room and recovered 8-9 1860-1870 indian head cents. The strategy was super slow with a 8 inch coil picking around all the iron carefully. I have hunted other sites where the targets were spread out thin and deeeep, the strategy there a big ass 15 inch coil and cover lots of ground. I have hunted sites polluted with shallow modern trash over the top of ground that gives up large cents, I discriminated the entire bottom 3rd of my screen and let the Explorer do what it does best pick off good deeper targets among the trash. Someone mentioned hunting in Oregon, its true their soil absolutely sucks and is hard to punch through so you typically have to back off the sens...though if you can stand the machine running wild for 30 minutes crank the sens and you might pick off a number of wheats and silvers as I did once in Washington Park, man hunting with the machine running that wild was brutal on the ears though.
Here's something practical on this topic. As I mentioned before rusty nails can pollute a sizeable area around themselves, this is a LOT more true when the ground is sopping wet. So there even soil conditions come into play on the same site. Personally if there are lots of rusty nails and the ground is sopping wet I won't waste my time on that site, I'll come back when the water has drained and the soil is still moist and the iron will be shut up quite a bit allowing me to get the good targets among the nails. I will also come back when the ground is bone dry, you don't get as much depth in bone dry soil but bone dry soil bitch slaps rusty nails and shuts them the hell up nicely.
Lastly, no rule of thumb is 100% true. About the time you think something is 100% true then you find an exception to the rule. For example there ARE targets that you can get a signal on with iron discriminated out that are invisible in all metal.
, the reverse is far more often true so I play the odds and hunt in all metal but I'm just saying, discrimination has its uses.
Charles