Indian Cent VDI question

[Digger]

I just recently bought another MXT, having sold my first one a year or so ago. I have a couple other machines that I like for particular hunting spots, but I like the MXT for summer hunting in yards and parks. I took the MXT on its "maiden voyage" this past week to a yard whose house was torn down several months back. I dug quite a few coins (pic attached) with a silver quarter and Barber dime being the best for that day. But the trash was really a nuisance. This yard was filled with pull tabs and screw caps. I know what some of you are thinking.....you got to dig the trash to find some of the treasures. Believe me, after 33 years of detecting, I understand that. However, after filling my pouch with pull tabs and screw caps, I finally elected to ignore those signals with VDI's of 24, 35, 40, 42 and the pesky screw caps at 57. I didn't find any Indian cents in that yard, and only a few Wheats. Wondering why I hadn't dug any, I decided to go through some of my Indian cents to see just where they registered on the meter. I found them registering anywhere from 30 to 70. Many of them hit solid on 57 and indicated a full bar of screw cap! Now I am wondering how many Indians I passed up last week in that yard? Guess only a trip back next week will answer that question. Anyway, my question to you coin-shooters is "if you get a reading of 57, how can you tell a screw cap from a coin without digging it up? thanks in advance. HH Randy

 

[BuckeyeBrad]

there is a subtle difference in the tone characteristic. The cap sharper and more abrupt while the coin will be a little "softer" leading on and coming off it. Also, USUALLY, the IH will be deeper than the more modern cap. Good luck with the return trip.

 

[DPW]

numbers in an area with high amounts of trash? I mean if an Indian Head is sitting below and next to a screw cap or pull tab or wad of foil etc. will the VDI be accurate? Even if you have the discrimination set fairly high that only affects the audio not the visual clues. The detector is still having to deal with two targets of differing electric conductivity. How can the VDI be accurate? Obviously this is where smaller coils need to be used but I believe MANY places have enough trash targets mixed in with the good to throw off the VDI.
Am I right? I just don't know for sure.

 

[Monte]

and it looks like you're enjoying it, too!

As for the Indian Head cent read-out .... well, most Indian Head cents (except the early 'fat boys,' and many of the early 'Wheatback' cents from 1909 into the early 1920's, will tend to 'read' a bit lower than a decent copper cent from the late 20's thru 1981 (and some '82).

Even though the books say they had the same alloy make-up, I have always attributed the reason for the lower reading (and easily discriminated) Indian Heads/Wheatbacks due to the impurities in the foundry process of making the copper. It doesn't really have anything to do with them being in the ground because I evaluated 'collector coins' early on just to verify my in-field conclusions.

Sadly, this 'lower-reading' tends to be very similar to and/or the same as the modern zinc cent or many screwcaps.

So, we have to either adhere to a 'Beep-DIG! approach to successful site coverage .... or .... learn some of the subtle audio characteristics of coins and screwcaps.

In addition, it takes a little time to learn the audio characteristics that can vary due to a different search coil than what you normally use.

Glad to hear you got some good stuff. If the older coins were in the 3" or greater depth range, then I'd suggest reworking the site with lower discrimination and then mainly go after the 'coin-sounding' targets that are suggested to be 3+ inches deep.

Happy 4th!

Monte

 

[shawnv(or)]

n/t

 

[shawnv(or)]

n/t

 

[Jeff in MI]

I would also add that depth reading is a good way of eliminating pull-tabs. For instance, pull-tabs tend to show zero depth. Also, when the signal is iffy, I flip over a little of the top soil, and I can generally get better info. So, like Monte stated, if it shows 3 inches or more and the signal is iffy, I dig.
First-and-foremost, that sharp signal that Buckeye pointed out is generally a dead give away for a pull-tab.

Jeff

 

[Monte]

Did I read that you were going to the Beaverstate Hunt?

Monte

 

[Digger]

The soil had been "stirred up" while they were tearing down the house. Pull tabs and screw caps were as deep or deeper than coins. I agree that depth would be a determining factor in your typical undisturbed ground. But I guess I will have to learn the subtle differences in sound for sites such as this. Thanks for the tips. Randy

 

[George (MN)]

I think screwcap IDs will vary alot depending on how flattened they are, just like we get a wide range of IDs for pulltabs of different shapes. The screwcaps may be louder & wider than a coins of the same depth, though I don't claim I can always be 100% positive which one it will be.

The penny IDs will vary alot according to corrosion differences (50-75 for the zincs). And those older pennies mentioned will be discriminated out (or given a low tone in relic center) when MXT is set to reject pulltabs. When trash & coin are next to each other, I think I've seen the detector give 1 ID mostly & occasionally give the ID of the other object, or something closer. Or maybe my sweep was not centered perfectly on some passes. But when I see these variations in ID or odd VDI numbers in a trashy area that I know are not due to depth, I approach the target from all directions, using short slow sweeps & sweep over the edges of the beep as well as the middle. And in high trash areas, if you ground balance on a clean spot, then use ground lock setting, this can add a slight bit to ID accuracy, sometimes making it possible to tell apart modern pulltabs & nickels (nickels 18-20, pulltabs 22+ except 20 if bent).

The 6.75" x 10" DD is the coil I use the most & with short sweeps from different directions can usually pick out some coins from heavy trash. But going over it again with a smaller coil would help get more I suspect. If in heavy trash, you can sometimes get correct ID on coin, but the confidence bars won't go up. This happened to me on a quarter. Turned out it was surrounded by iron.

I use the relic center mode with disc at 3 o'clock so coins except nickels give a high tone & most trash like iron, foil & pulltabs give a low tone, but are not actually rejected. This may help reduce target masking & the high tones really make it easy to find many coins in high trash without having to look at the screen constantly. HH, George (MN)

 

[DPW]

Your post helped answer some questions I've had. I think the MXT is great. As little time I get to detect it's going to take sometime before I get it all figured out.It's been about three weeks since I was out last. But I sure do enjoy it when I'm out there.