Just got smacked between the eyes by the obvious.

[Mick in Dubbo]

Sometimes the blatant obvious isn't so obvious. I was mucking around at home with a few of my detectors, mostly both the X-Terra's and found a dead simple way of telling pull tab from coin.
Des Dunne made an innocuous comment in a nearby post about the X-Terras being tuned to give solid signals on round items, so I thought that it would be fun to play around with various targets to se what happened.
When I got to play with some pull tabs, I wanted to see if there were any clues that I may have previously missed. I discovered with the Ace, that not matter how solid a lock a pull tab would give, they seem to give themselves up by pass 5 by bouncing notches. As our 10c piece shows up as a 12 on both the X-terra 30 and 70, so do the square pull tabs. Even on the Explorer's smart find screen, these 2 targets are almost identical. They are only a single value apart, usually. I come across 2 main types of square tabs. The ones with sharp corners is usually fairly easy to pick due to the rough tone and they bounce around on the meter fairly easily. The other type of tab, which are becoming a lot more prevalent over the last 18 months, have rounded corners. These are a lot harder to figure out from coins, as it fools the detector into thinking (metaphor) that it's a coin. As pull tabs hit fairly strongly on notch 12, they still tend to bounce, mostly up. What I've found is, that I notch out 14 on the X-terra 70 and 16 on the X-Terra 30. What this allows to happen, is allow the 10c cent piece ( you US uses can put your V nickels in here) to give a mostly consistent signal, while pull tabs will give an inconsistent audio signal due to these notches being rejected. On the X-Terra 30, when you come up on a rounded pull tab, it will still fool you due to the wider notches, but it will identify pull tabs far more easily.
Mick Evans.

 

[Jack Flynn]

You are spot on with that analogy. Des also mentions putting the 70 in 99 tones and running the coil over a suspicious target. In that mode it flips a note or something like that for a lack of a better description. I've dug one pull tab in the last 4 outings using this method and was fooled just because it was 2 tabs inter twined with each other. It takes only a second to switch from 4 to 99 tones then back once the target has been identified.

 

[Mick in Dubbo]

I was a little off on who said what. It was actually Jackpine Savage who directed a question to Andy Sabisch in the thread "New X-Terra's 305/505/705" Great question/comment Tom.
Yeah, what Des said about the 99 tones is spot on. I played around with it some more tonight and found that the best info seemed to come from the concentric coil. the tones don't seem to be very clean in 99 tones (is that normal?) but the amount of target info is remarkable. I was also noticing that screw caps give a distinctly different tone to a coin, unless it's been squashed fully flat, but then you still have the VCO to help further.
I really wasn't expecting that the 70 would produce much more information than the 30, but It has. Once the hours mount up on it, it's going to be hard to put it down, as I think that it will produce all the target information that's needed to figure what they are.
Mick Evans.