24 notch vs. 12 notch discrimination

[jlopez5555]

I just realized what made the GTAx series such good detectors. It was having more discrimination settings. This allowed more specific "junk" to be tuned out while still allowing gold to come in. This is why with todays detectors you must dig everything in pulltab range to have a shot at gold. The GTI and GTAx series are much heavier because of the processors needed so I guess that's why they no longer have this much discrimination but man do I wish the AT would have come out with 24 notch discrimination. Do you more experienced hunters have a preference either way?

 

[TheMarshall]

That must be the crappiest realisation you've ever had !!!!!!!

QUOTE:-

I just realized what made the GTAx series such good detectors.
It was having more discrimination settings.
This allowed more specific "junk" to be tuned out while still allowing gold to come in.

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So you've never seen or used a Whites ' 180 plus' notch detector?

Or a Minelab 2 dimensional discriminator?

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More quote....


"This is why with today's detectors you must dig everything in pulltab range to have a shot at gold."

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Now that's talking sense.....

So what then are you 'notching' out ?

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Attishoooo *^$+/......getting cabin fever.....sorry.

 

[jlopez5555]

So do you think the number of notches matters or do you normally just dig everything.

 

[slingshot]

Let's just put it this way: Gold, depending on it's alloys and shape,size, or it's positioning in the target matrix can fall in any of the 12 OR 24 segments.

 

[jlopez5555]

I understand that it can fall anywhere but the 24 notch detectors can be set up to discriminate most trash and pulltabs and still get solid beeps on mens gold rings. I think with the AT Pro you won't be able to discriminate as good but you will be better able to tell by the digital ID.

 

[TheMarshall]

So do you think the number of notches matters or do you normally just dig everything.

Hi there JL...!

Yes, I dig virtually everything, but that reply must be viewed in it relation to the sites I detect.

They are farm fields generally, here in the UK.

The 'junk' factor is mainly iron, or cattle mastitis tubes.

Alternatively, I search wet beaches.

For the fields, my disc is 'open' from minus 20 up to plus 94.

The mineralisation we experience is moderate to reasonable, so we anticipate that 'in air' numbers are down-graded to unpredictable values.

Hence we don't search by any notch techniques. Only obvious iron is rejected (minus 35 to minus 95).

All the other targets must be dug to capture those odd elusive antique artifacts.

Our problematics are 'coke' (Burned cinders) from old farm traction engines, and rusty iron, modern or centuries old nails etc.

I appreciate your dilemma of junk laden parks, but too much rejection will surely deny you some jewelery.

I would suggest you detect and dig more based on the audio quality of your signals, rather than a single VDI number.

Steady, repeatable, from at least two 90 degree different sweep directions.

On the wet beaches, I reject minus 95 to plus 8, and quickly dig the rest.

Be a metal detectorist and not a metal rejectorist, or you may never know what you've missed.

Just my opinions J......'nothing written on stone'

All the best.

TheMarshall

 

[SteveP(NH)]

I understand that it can fall anywhere but the 24 notch detectors can be set up to discriminate most trash and pulltabs and still get solid beeps on mens gold rings. I think with the AT Pro you won't be able to discriminate as good but you will be better able to tell by the digital ID.

They are actually the same - if you look at the first 4 notches on a GTAx machine they are down in the iron range, leaving 20 that aren't iron. On the AT PRO the iron range is covered by the first 40 target ID numbers and there aren't any notches for iron. So both machines have 20 notches for non-ferrous targets.

However the really important thing you seem to be missing is that if you are notching out pull tabs then you are leaving behind gold. A big man's ring that is alloyed with a lot of silver will come in higher, but the 18 carat wedding bands (worth more per gram) come in on the same notch as pull tabs. The old saying that "if you want gold then you have to dig pulltabs" is true and there is no way around that with current technology.

Also I think the point the other fellow was making is that if you are going to use notch discrimination you can do a lot better than 24 notches and that there isn't really much difference between 20 and 24 when it comes to being able to discriminate out junk and leave good targets behind. His examples were that a high end White's machine has what amounts to 198 notches and an FBS Minelab has 1024 notches so 20 or 24 - doesn't matter - both aren't very many to start with. I own two other machines right now - one is a Whites with the 198 notches and the other has 99 notches and I don't use the notch system on either them cause I have learned that you can't notch out just trash - I dig all non-ferrous targets now and some of the ferrous one, though I don't hunt public parks any longer, there are better places for my style of hunting so I don't run into big concentrations of anything except nails.

 

[Waterdog]

I was out detecting with a friend about a year and a half ago. We was doing just Tot lots that day. Someone had been in most of them before us. Funny thing was that all we was finding that day was Pull tabs, Nickels, and Gold. Got to love those discriminators..

 

[NM5K]

I don't think it would really matter much to me for most targets. I would be afraid to
leave something in the ground just because it didn't exactly match a given ID by
one notch.
AT Pro? Being it has a numerical readout, and assuming it is from 0-99, or
maybe 10-99, or whatever, it has almost 100 notch discrimination. 80+ anyway..
That's the whole purpose behind the numerical ID. Very fine resolution.

 

[SteveP(NH)]

I don't think it would really matter much to me for most targets. I would be afraid to
leave something in the ground just because it didn't exactly match a given ID by
one notch.
AT Pro? Being it has a numerical readout, and assuming it is from 0-99, or
maybe 10-99, or whatever, it has almost 100 notch discrimination. 80+ anyway..
That's the whole purpose behind the numerical ID. Very fine resolution.

You can only use the TID numbers to discriminate out iron from 0 thru 39 and then you can't notch out anything, it is a linear discriminator in the iron range so you could discriminate out from 1 thru 20 or from 1 thru 30 buy you can't do from 20 thru 30 (accepting 1 thru 20 and then discriminating out from 21 thru 30).

Above 39 you can only notch out targets using the notch tabs. Each notch tab is equal to 5 target ID numbers and you have to knock them all out or accept them all.

But the notch system isn't important to me as I don't use discrimination - I want to hear all of the targets and then decide based on the audio and the target ID numbers whether to dig or not but then I dig all non-ferrous and only decide not to dig some of the iron.

 

[NM5K]

I'm the same way.. I don't actually notch out any tabs. I was talking more of the IDing
of targets and whether to dig or not. One notch worth of conductivity would not be
enough for me to make a decision. So to me, having the extra resolution doesn't
really mean a lot at the end of the day.
But as a light and blinky thing, they are kind of nice to have. The numerical ID
is probably most handy for guessing coins, but even then it's hit or miss depending
on how much leaching there is. It's not going to be exactly the same every time.
I almost always run mine wide open. I like to hear everything that is in the ground.
The only exception might be if say I'm on the side of a house, and nails from
re-roofing are a constant problem. You can notch the low end.. But even with those,
if they are rusty, they will hit high too.. So if you notch the high end rust, you risk
notching out the coins too. I'll usually run it wide open, and that way I can hear
both ends, which to me gives more total info. IE: if a target is bouncing both ends,
it's almost always trash, or rusted iron. If I had notched the low end, I might not
notice the bouncing back and forth, and would dig on the high rust hit thinking it was
a coin. One thing I've noticed that doesn't seem to vary much. Actual coins,rings,etc
rarely bounce around on the ID much. They usually ID pretty stable every swing.
Unfortunately, many pull tabs are pretty stable too..