Missing very shallow targets:

[Mtnmn]

Would anyone know why my XT-70 was apparently missing out on quite a few very shallow targets (under 1 1/2")? I just got a Safari in hopes that it would go a little deeper than the XT-70, but surprisingly in this one area it is finding quite a few very shallow coins and not many at all in the medium to deep range. This is on ground that I thought I had cleaned out with the XT-70. Could it be that I was running my sensitivity too high (28-30) on the XT-70 or is the Safari apparently a little better at target unmasking than the XT-70? This area does have a lot of shallow modern day trash such as pull tabs, screw caps, can slaw and so forth. My guess it is a combination of the two, too high of a sensitivity setting wouldn't have allowed the XT-70 to unmask targets as well as a lower setting would have.

 

[David]

Yes, my guess is the trash masked the XT-70 from seeing the very shallow good targets. Then the Safari was better at unmasking than the XT-70. The Safari(FBS) has a stronger discrimination than the XT-70 because I contacted Minelab and I think Dick Shultz told me that the Sovereign GT(BBS) had stonger discrimination than the XT-70. So thus I gather the FBS and BBS units are better at unmasking in trash than any single frequency VLF.

Would a lower sensitivity setting on the XT-70 unmask targets better, I do not know?

Also the Safari will handle higher mineralization and wet saltwater sand better than the XT-70(or any other single frequency VLF for that matter), and will go a bit deeper as well. But the disadvantage of the Safari(FBS) is it needs a slower sweep speed and will be less sensitve to very small gold than the XT-70. Dick Shultz also told me that the Sovereign GT(BBS) is not good for gold nuggets smaller than about 1 gram.

PLEASE DO keep us informed on the XT-70 vs Safari!

 

[Furious T]

My guess also is that you were running the sensitivity too high for that area on the X T 70. The Safari possibly managed a little better because it is a multi frequency machine.

 

[Digger]

My guess is that you are sweeping the Safari slower than you were the X-TERRA. If you are like most of us (and I am including myself), when we get a new detector, we operate it much more methodically than we do the one that we've become more familiar with. Add to that the fact that we constantly read how the FBS and BBS detectors require a slower sweep, that is exactly what we do.

Next time you're out, take them both with you, along with some poker chips. When you get a target with the Safari, don't dig it. Instead, drop a poker chip on top of the target and keep hunting. After you get a few chips laying on the ground, switch over to the X-TERRA and see if you can't find those targets under the chips. Subconsciously, now that you know there is a target hiding down there, you'll sweep the X-TERRA slower in an effort to find it. And if that is the case, (as it has been 99% of the time when I compare my E-TRAC to my X-TERRA) you'll have proven my point. JMHO HH Randy

 

[Mtnmn]

Randy: You may be right as I have definitely have been swinging the Safari slower than the XT-70, but only because that's what you have to do for the FBS detectors to be most effective. Will try what you said, but if that was the case why was the XT-70 finding almost all the coins in the 1 1/2" to 6 1/2" range?

 

[Digger]

If you are sure you were walking over them, then I'm stumped. Speaking strictly from an electronics standpoint, the transmit signal that went down and energized those 6 inch coins had to pass through the first inch of dirt to get to them. If it is a trashy area, Sensitivity could play a role. But before I do any more guessing, give that test a try.
I know I make a real effort to slow down the sweep speed on my BBS and FBS detectors. But honestly, I think that having a V - E - R - Y S - L - O - W sweep speed is over-rated, as far as being effective. If you listen intently, you can pick out targets just fine with the Safari sweep speed similar to the X-TERRA. And if you can't, then I'd say you were sweeping the X-TERRA too fast when you were using it. Which takes us back to your original question. JMHO HH Randy

 

[Mtnmn]

I already have been picking up my swing speed with the Safari, I now pretty much let the amt. of trash dictate on how fast I swing it, pretty much like with the XT-70. That area does get some use year around and throughout the winter, so maybe the coins got there since the end of last summer which is why they were so shallow, usually about an inch. Don't some detectors now have what could be referred to as or is a deep search mode, what is changed to put them in that mode? Just curious?

 

[Digger]

Deep search mode is typically the automatic adjustment of specific settings. Usually either the Ground Balance, Sensitivity or both. It constantly analyzes what is under the coil and "fine tunes" the settings to maximize the depth of detection. Particularly in highly mineralized soils. It doesn't let you pass up shallow targets. It just maximizes the performance (depth) based on soil and target properties. JMHO HH Randy

 

[David]

Mtnmn, try this masking experiment. On the top of the ground put those coins(copper,silver,and/or clad) you found => underneath, over top, and then beside a piece of iron, nail, foil, and/or pull tab. Set up a test bed, try the XT-70, then try the Safari. What happens??

 

[Mtnmn]

Thanks Digger! Today took the XT-70 out to a friend's yard that I had never hunted before (late forties house and yard) and had my best day ever: Seven Wheats, two (both 52) Rosie dimes, one (43) Merc. and a 1816 to 1839 Liberty Head large cent which had been made into a medallation by drilling two holes in it and for some reason they drilled one of the holes right thru the date! So the XT-70 still has what it takes. Took it over the Safari because it seems to I.D.'s coins better and I didn't want to dig any more holes than necessary. The good thing about this is I've only covered about 1/4th of their yard. Sorry about no pictures, but I don't even own a camera yet!.

 

[Digger]

Sounds like you had a great day. Congrats on all those finds. Glad you got out and that it worked well for you. HH Randy

 

[Mtnmn]

After much cleaning and using 10x magnification, the medallion turned out to be an 1826 Matron large cent. It must have been drilled for use as a bracelet as the Liberty head was facing the wrong way to have been used as a necklace. If history could only talk...

 

[Digger]

Nice recovery, regardless of the condition. And I agree with your comment about history. If only??? I've been detecting for nearly 40 years and have yet to find my first LC. My ancestors came here when this land was first "opened up" to settlers. (1854) I can't tell you how many times I've wished they would have stopped a couple hundred miles East of here! Sure would have made the odds of my finding a LC more likely. But as I keep telling myself, it's all about the hunt! HH Randy

 

[Mtnmn]

I have the same problem as you, my area never really started getting settled until the 1850's because of its remoteness. If this coin hadn't been turned into a medallion for a bracelet, it would have never ended up where it did. Amazingly one of the kids who grew up in that house back in the fifties, only lives a few miles from me and I'm almost certain that he had an older sister. I might be able to trace the history of this medallion (coin) after all, if his sister is still alive. Wouldn't that be something!

 

[David]

Mtnmn, that is the very last time I will make the effort to help you. You could have said "that is not a good idea and/or I do not want to try that" but instead you totally ignored both of my posts. Good bye.

 

[goldseeker4000]

Digger, is it possible that mtnmn is searching in one of the preset modes and the descrimination setting are masking out certain coin types, like you mentioned in your article what are you walking over and missing? I did this very same thing last year while coin hunting. I did not know that some dimes pennies and nickels as well as gold, platnum and some silver was masked out in #2 mode of my 705. Because I was hunting in this mode in a vacant lot, to not have to dig trash, I missed a 1905 V nickel, an 1882 indian head penny and countless wheaties. I was frustrated and pissed and was having doubts about the 705. It wasn't until last night (3/22/2011) that I stumbled onto your article on what you may be missing that it clicked on why I was missing some coins and my friends had found them. I had passed over that ground many times over and never found them. I will be opening up all of those notches that you mentioned for program mode 2 as well as hunting in AM first and then double checking in mode 2.

 

[Digger]

Thanks. Glad you found that article. But for the record, the TID number will be the same, no matter whether you are hunting in a Pattern or in All Metal. The only difference is that when a certain target's properties have been set to reject in a Pattern, you don't get an audio response. The TID number still appears. But again, you just don't get the audio report. What I've done is make my own Pattern that accepts all target properties, except -8 and +48. Knowing that the -8 notch and the +48 notch are "narrower" than the other notch segments, rejecting them accomplishes two things for me. One, it helps eliminate the "wrap around" tone I hear on deeply buried iron targets. And Two, when I stop the hunt and put the detector away for the day, it starts back up with that same Pattern the next time I turn it on. As you know, the X-TERRA starts up in the last Pattern mode that was used. So if you are hunting in All Metal mode, when you start it back up it will NOT start up in All Metal. It starts with the last Pattern used. If you want All Metal, you have to change it to All Metal mode to hunt that way. By saving my own Pattern, with mininal discrimination, I know that the next time I turn on the X-TERRA, it will be right back where I left it with all notches accepted except -8 and +48. If you don't want to reject the -8 and +48, you can build a Pattern that accepts or rejects any TID number(s) you want. Then simply save it as a new Pattern, and enjoy the fact that the next time you turn on your X-TERRA, it is set up right where you left it. JMHO HH Randy

 

[Mtnmn]

Dave: I'm sorry that I offended you. It was not intentional , though it was inconsiderate of me to not get back to you in a more timely manner. I did appreciate your input on 3/21 and should have acknowledged both it and your later request. I have a lot of pots in the fire and when combined with everything else, it makes it very difficult for me to try and honor other peoples requests other than just giving out advice. Will try and do better in the future.. Mtnmn

 

[Mtnmn]

Digger and Goldseeker: I have always run the XT-70 in Pattern one with nothing else notched out. My final guess is that the coins were apparently lost since last detecting it in or around August which might explain why the coins were still in among the roots of the grass. (The place receives regular usage year around). I may have created a big flap over nothing. Sorry about the inconvenience!

 

[Mick in Dubbo]

It's very disconcerting to know that you are missing targets. I've found that the 2 primary causes are the need to noise cancel and the standard coil seems to contribute to the problem. I find that the 5x10 coil seems to be a lot more reliable at hitting targets. Our Aussie $2 coins (which hit like US Zinc pennies) were the ones I noticed it on most, being a bit smaller at around three quarters of an inch in diameter. Apart from having a bit of a dead spot on the toe of the standard coil, it also seems to be affected by EMI a lot more than we realise, most particularly when you don't noise cancel, be even if you do. It's a bit of a shame, as I like the audio of the standard coil. The high frequency DD coils seem to be unaffected by EMI, thann when you don't noise cancel, although noise cancelling does help.. You don't realise that the X-Terra's are being interfered with, by EMI because they seem to sound stable. Unlike a lot of detectors that start falsing badly, when the X-Terra's suffer, you just think that you are going over junk signals. The other clue, is that all targets will max out the depth indicator on all targets.
So if you run a 5x10 or 6in DD high frequency coil, it should eliminate that problem. (plus use the noise cancel.)
Mick Evans.
P.S. If you swing your coil too fast, then that will cause you to loose target due to target masking. If the ground if really trashy, go slow enough to allow you detector's circutry to keep up.