TID is shifted +4 on my X70

[MT_VertCaver]

I've been noticing that my X70 TID's are consistently +4 over the TID chart in the FAQFAQ. It's been that way for pennies and quarters. I was thinking that maybe it's happening just because the soil is REALLY wet right now and I'm a new user. But then I had a thought.....


I've been using Pattern 1 because there's just too much iron(nails, etc) everywhere I've been hunting. If my detector is adding 4 to the TID...am I missing half dollars because 48 is discriminated out?????

Just did a quick test. I put a clad half and a clad quarter on the lawn and tested. Sure enough the quarter is 44/46(as my experience has shown) and the half 46/48.

So I guess I'll have to accept 48 on my machine.


Now the other question....Is the whole scale shifted higher???? OR Is the scale just shifted MORE on the upper end???

I don't know yet.

(I'm mostly using the 5x10 HF DD coil)

 

[S505]

I only saw the shift in tests in soil. Never when the targets were on top of the soil. It affected all targets that I checked and they ranged from -9 to 45 (expected IDs based on air tests). The shift, up or down, whichever was occurring, affected the nickel range of the scale to a much larger extent than the silver range.

Since you are seeing this on the surface I am unfamiliar with it (it might be that your machine always has a bit of a bias), but I suggest you always accept all notches (search in all metal) and ignore 48's only if they are accompanied with iron signals from the same target.

S505

 

[SeniorSeeker]

A number of times I've read, in posting of others using the Minelab X-terra 70/705 that they have #48 descriminated out and, for the life of me, I can't figure out why? My goodness ... just about every quarter, half-dollar, or silver dollar I've found comes in around 44-48! Why would anyone want to block out #48? Makes no sense to me whatsoever. I spent two years getting to know my X-70 and found just about anything I had hoped I'd find, with the exception of really old, old coins, and found enough the first summer to pay for the machine. I never - repeat - never discriminated #48 out at any time. Please explain this to this 'Ole boy, if you please.

 

[Terra1959]

Hi,

As I understand it, different coils can change your TID no's
....I also thought that this is a fairly common occurance across all brands and coils
The 5x10 HF DD coil moves my Xt70 by 2 (over the standard coil)
Perhaps G.B, soil or target conditions move the other 2 ?
Are you in Tracking ?

I listen more to the tone and then I check the target by waving the coil across it in fairly fast, tight little multiple swings, if it stays fairly consistant. I dig

T59

 

[Digger]

I'd check my batteries as weak batteries or even one weak cell can give misleading TID values. I'd also do a system reset, where all values are set back to factory default. If the numbers are skewed after that (when using the chart and your MF coil), call Minelab and see if their techs have any other suggestions. Might be something that requires a trip to the service center.

In checking my coils with the 705, I found that a US Morgan silver dollar will read a 46 on all of them at a distance of more than two inches. Concentric and DD. However, it reads a 48 on that same silver dollar, using my three HF DD coils at distances of 2-inches or less. A US silver half dollar is one notch less, under the same circumstances. I don't have the HF concentric, so I can't determine if the variation relates to frequency or DD design.??? If someone has the 9-inch concentric at 18.75 kHz, I'd like to know what reading you get on an old silver dollar at the depths mentioned above. Then maybe we can determine whether the frequency or the coil design is making the difference. Thanks!

The coin chart was developed using the stock coil, as I figured everyone got a 9-inch concentric at 7.5 kHz when they bought their detector. Although I mentioned that TID numbers could vary with conditions, since the introduction of the "gold pack" HF elliptical coil version, I should probably reference the HF coil variance on the chart.

JMHO HH Randy

 

[MT_VertCaver]

This last week I've been sick and busy(taxes and I got roped into building a website)....so no testing yet.

Digger...when I get a chance, I'll try your suggestions and then report back here.

 

[David]

SeniorSeeker, you are right then. As Randy(Digger) said if a silver dollar shows 48 at 2-inches or less then a person could miss a shallow silver dollar if 48 is blanked out. But the reason a lot of people blank out 48 is because 48 also shows a worthless hotrock when in rocky mineralized areas(and sometimes there are a lot of hotrocks and they can drive a person nuts), then in black dirt-sod areas always leave 48 on and open.

My 10.5" HF DD coil has higher numbers being different TID numbers than my stock MF CCoil. The MF CCoil has lower TID numbers that is why a CCoil is called more accurate than a DD coil. BUT is that because of DD Coil vs CCoil and/or HF vs MF.???

I would want a 9-inch HF(18.75 kHz) ConcentricCoil test the same as Randy does. BUT I would like to know if that HF CCoil also(like the HF DD) shows higher TID numbers than the stock MF CCoil.??? OR the same TID numbers for both of these CCoils.???

 

[MT_VertCaver]

I did a full system re-set like Digger suggested, but didn't change the batteries. I went back to the park...and everything seems to work like normal again(generally I get +2 TID on everything).

So, I guess I just had a weird day last week????????