Masking??

[Rebel1]

Ok, i got my new Tesoro Compadre back from Tesoro today. I had to send it back because there was a bad connection in the coil wire. They re-soldered the connections, checked it all out and ok'ed it and sent it back to me. I mailed it to them last Mon. they received it Thurs. and i got it back today. Great service. Anyway, i took it and my Ace 250 out in the yard to do some testing. I put a dime with a piece of foil under the dime, then over the dime, then right next to the dime. Did the same with a quarter and a new type pull tab. Then set the Ace on jewelry mode and the Compadre discriminate at iron. Now the question. I got readings with both machines on both of them. When i moved the disc. up to $.05 on the Tesoro i still got readings on both of them with it and with the Ace no matter if the foil or tab were under, over, or beside the coin. Is this good, normal, or what? If normal what exactly is masking and how does it affect my detecting? If i am in a trashy area and get a tone with the Tesoro on A/M and then start turning the disc all the way up and still get a tone i can assume it is a coin or silver? Sure wish i had somebody here close to learn all this from. Take care and thanks for any help.

 

[fwcrawford]

Hopefully others of more experience than I will answer your post, but I will help you out as much as I can.
I think most folks when referring to "masking" are talking about hunting a site that has bits of iron both large and small such as rusty nails, part of iron kettles, and endless types of scrape iron from who knows what.
When a good target such as a coin is laying next to, underneath, or on top of this iron, many times the detector when in the discriminate mode will "null" on the iron or ignore it and also not pick up the coin signal or maybe not give a very good signal. Many folks resort to smaller coils to get in between the coin and the iron so this does not happen or hopefully is reduced. I guess setting the discriminate to ignore the foil and the pulltab you used in your test could mask the signal on the coin also or make the signal sound like it is only trash although the coin is there also.
Try the same test with a nail or other small iron object and set the detector up to ignore that and then place the coin next to it or nearby and then try swinging over it to see what kind of signal you get.
Now this is not going to tell you how it is going to react in actual hunting conditions due to the fact that the nail that has been in the ground for many years develops a "halo" and leaches into the surrounding ground which make is look larger than it actually is. They will often fool you and give a very good signal until you dig it up and then most often it will not sound off at all.
Hope this is of help to you and not confusing.
Felix

 

[Rebel1]

Ok, i took both detector back out and set the test back up. This time i also took a rusty nail. They both picked up the coins with the foil nulled out and with the pull tab nulled except they would no longer pick up a nickle. The rusty nail made it a little more difficult. I disc'ed out iron until i no longer got the nail then put it on top and beside the coins. They both got the quarter ok. The dime was harder. I got a broken signal with the Compadre and a decent signal going left to right with the Ace but none right to left. Also no signal if going the length of the nail instead of across it. CONCLUSIONS??

 

[fwcrawford]

That sounds about normal as far as the response when the nail was in the picture.
The reason the nickel would not sound off is because when you set your disc. to reject the pulltab, it also rejects the nickel because the nickel falls below the pulltab on the conductivity scale.
In other words the nickel is a lower conductive target than the pulltab.
Also by setting the disc to reject the pulltab, you will also be rejecting most gold rings which is why when hunting for gold jewelry, you have to set the disc. lower and dig the pulltabs also or you are likely to miss the rings as the detector will not sound off when swung over it.
Felix

 

[Rebel1]

Yep, i dig most every signal anyway, i just wanted to test the 2 of them side by side and see how much, if any difference there was. I am keeping the Ace and selling the Tesoro. The Tesoro is a nice, lightweight little machine and is near new, but i have all 3 coils for the Ace and i think it will do everything i want from a detector.

 

[gmanlight]

Try burying the dime at say 4 or 5 inches then use the nail and foil on top of the ground were you can move them around to test.
Everything changes with some depth and separation between the objects HH Mike

 

[Neil]

Try burying the dime at say 4 or 5 inches then use the nail and foil on top of the ground were you can move them around to test.
Everything changes with some depth and separation between the objects HH Mike

Boy you got that right. just adding the dirt in the testing makes a difference. how many times have we all dug what sounded like a good target only to pop it out of the ground and have the detector go silent over it when its on top of the ground?

Neil

 

[Rebel1]

Thanks for the good idea, i will try that next. Yep, i have dug a signal and found Nothing except RUSTY soil.