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Why is TTF the best option for iron laden sites
Posted by: Bob38
Date: January 29, 2019 12:09PM
OK, I know TTF is a good approach to iron laden sites but why? My theory is this. When in the conductive audio mode you may have rusted halo around the iron (highly likely as a matter of fact) which will present the opportunity for this halo to sound like a conductive target. By switching to ferrous you are letting the iron be iron (halo included) and only truly conductive targets you will hear. In other words, by switching to TTF you take away the opportunity for this ferrous halo to sound off like a solid conductive target.

If I'm wrong or have a better explanation please correct me. I'm the kind of guy that needs to know why things work the way it works to completely understand.



Etrac, Whites V3i, Equinox 800, XP Deus, Whites SL., Wiener dog and understanding wife

Re: Why is TTF the best option for iron laden sites
Posted by: IDXMonster
Date: January 29, 2019 12:12PM
I personally believe what you said to be true Bob. I am of the same mindset!

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Re: Why is TTF the best option for iron laden sites
Posted by: Bob38
Date: January 29, 2019 01:25PM
Thanks, IDXMonster for your concurrence. Hopefully, I can get others to chime in to reinforce my/our belief.

Re: Why is TTF the best option for iron laden sites
Posted by: IDXMonster
Date: January 29, 2019 06:56PM
Bob....if you Google “Metal detector Basics and Theory” you will find a great read in part by Bruce Candy,who we know as one of the main physicists responsible for Minelabs success. It’s slightly “techy” but an easy read,and to me,fascinating. The more we know about HOW things work(facts) the more we can rely on our knowledge in the field! We can’t make adjustments for everything,nor even know for sure what lies beneath,but knowing WHAT to adjust and WHY leads to success. Every time. Enjoy...

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Re: Why is TTF the best option for iron laden sites
Posted by: Bob38
Date: January 29, 2019 07:44PM
I will look into this. And you are right, the what and why does lead to success. I'm preparing for some high potential sites that I have been researching for some time now and I don't want to rush into things until I feel that I am somewhat proficient enough. At least proficient enough to realize what needs to be done to make the best of it. TTF has fascinated me for about a year now and is only a part of the possibilities to explore.



Thanks for referring me to the Bruce Candy write up. I will read it.

I'm going to disagree....
Posted by: Chris(SoCenWI)
Date: January 30, 2019 10:55AM
Bob,

When the Explorer XS came out 20 years ago the manual made much ado about using a ton of discrimination and "teaching" in good targets. It would have been nice if it worked, but, in real world conditions where there is a ton of targets under the coil at any one time, the great majority of targets don't consistently hit where they are "supposed" to hit. If you are running a lot of discrimination most of the time these hits will cause a null and not a signal. I ran with what the book told me to do with patterns for a week or so, then started realizing that I was missing a ton of good targets. By opening up the screen you no longer got a null. It might not hit in the "supposed" spot every pass over the target, but you still got a noise instead of a null and could look at where the cursor was bouncing.

Pretty soon I had the screen almost totally open, but with iron targets being the predominant trash target the machine was still nulling most of the time. In conductive tones you can't completely open up the screen because nails and iron sound like silver. Many of us then switched to ferrous sounds, where higher conductors give a high tone and iron a low grunt. Basically this keeps the machine from nulling out and lets you listen to everything. I only discriminate out where crown caps hit, lower right of screen in XS speak, because they also give a high tone in ferrous.

It was interesting to watch over the years newer folks come to the forum and reach the same conclusions through their own experimentation; that less discrimination was better. It was a bit controversial at first but I think over half of the XS swingers ended up being ferrous people.

When the Etrac came out the equivalent set up became to be known as TTF- Two Tone Ferrous. As with the XS, you had to be in ferrous to open up the screen. On the Etrac and later models Minelab hugely dumbed down the machine and made pretty much every target other than iron have a ferrous value of 12, that is why it is called Two Tone- Iron grunt or one other sound. On my XS I can tell a nickel from a dime from a Indian head in ferrous sounds and the cursor bounce over the whole screen is also invaluable.

So... In answer to you question. In conductive iron itself sounds like silver, it gives a high tone, if you open up the screen every nail in the world will sound good. So you need to switch to ferrous. Iron falsing- halo effect- actually I'm not sure it is the halo or rusting that causes this, is still a problem in Ferrous mode. Some iron, particularly bent square nails or some round items, can sound much like a coin. I still dig my share after 20 years using the machine, and this seems to affect all the machines I've used equally.

Basically TTF works because in iron laden sites you are not continually detecting in a null. Shallower good targets will often give a signal, but you miss a ton of other targets. In ferrous you will get an audio response.

Chris

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Re: I'm going to disagree....
Posted by: Bob38
Date: January 30, 2019 02:27PM
Chris

So TTF just takes care of the constant null and the numerous high tones we get when hunting in conductive audio. High tones will still be encountered with bent nails and big iron rings and various other bent iron. So I am doing it right. Have yet to dig a deep silver but have pulled some big old rusty rings and nails. Avoiding those are almost impossible. I think I just have to slow down and work the patch more methodically.

Thanks for the reply Chris this really puts me on the right path.

Re: I'm going to disagree....
Posted by: oneguy
Date: January 30, 2019 06:48PM
Quote
Bob38
Chris

So TTF just takes care of the constant null

It's the disc you use that creates the null either in conductive or TTF. I'm a big fan of TTF and use an almost open screen....



Minelab Gold Monster 1000
E-Trac (13" Ultimate, 6" EQ2, NEL ss, Pro, X-1)

Re: I'm going to disagree....
Posted by: IDXMonster
Date: January 30, 2019 09:13PM
Quote
Chris(SoCenWI)
Bob,

When the Explorer XS came out 20 years ago the manual made much ado about using a ton of discrimination and "teaching" in good targets. It would have been nice if it worked, but, in real world conditions where there is a ton of targets under the coil at any one time, the great majority of targets don't consistently hit where they are "supposed" to hit. If you are running a lot of discrimination most of the time these hits will cause a null and not a signal. I ran with what the book told me to do with patterns for a week or so, then started realizing that I was missing a ton of good targets. By opening up the screen you no longer got a null. It might not hit in the "supposed" spot every pass over the target, but you still got a noise instead of a null and could look at where the cursor was bouncing.

Pretty soon I had the screen almost totally open, but with iron targets being the predominant trash target the machine was still nulling most of the time. In conductive tones you can't completely open up the screen because nails and iron sound like silver. Many of us then switched to ferrous sounds, where higher conductors give a high tone and iron a low grunt. Basically this keeps the machine from nulling out and lets you listen to everything. I only discriminate out where crown caps hit, lower right of screen in XS speak, because they also give a high tone in ferrous.

It was interesting to watch over the years newer folks come to the forum and reach the same conclusions through their own experimentation; that less discrimination was better. It was a bit controversial at first but I think over half of the XS swingers ended up being ferrous people.

When the Etrac came out the equivalent set up became to be known as TTF- Two Tone Ferrous. As with the XS, you had to be in ferrous to open up the screen. On the Etrac and later models Minelab hugely dumbed down the machine and made pretty much every target other than iron have a ferrous value of 12, that is why it is called Two Tone- Iron grunt or one other sound. On my XS I can tell a nickel from a dime from a Indian head in ferrous sounds and the cursor bounce over the whole screen is also invaluable.

So... In answer to you question. In conductive iron itself sounds like silver, it gives a high tone, if you open up the screen every nail in the world will sound good. So you need to switch to ferrous. Iron falsing- halo effect- actually I'm not sure it is the halo or rusting that causes this, is still a problem in Ferrous mode. Some iron, particularly bent square nails or some round items, can sound much like a coin. I still dig my share after 20 years using the machine, and this seems to affect all the machines I've used equally.

Basically TTF works because in iron laden sites you are not continually detecting in a null. Shallower good targets will often give a signal, but you miss a ton of other targets. In ferrous you will get an audio response.

Chris

Not sure what you are “disagreeing” with Chris? He is running in Ferrous with TTF,simply splitting the screen top and bottom...and not nearly the fluctuation as the Explorer because of the “normalization” to the 12 line. Am I missing something?

Re: I'm going to disagree....
Posted by: Chris(SoCenWI)
Date: January 30, 2019 10:20PM
Kevin,

Nope, I guess I was disagreeing that it was the halo that was made open screen conductive impossible, when it is iron itself. And I had to do my normal rant on how much worse the target ID is on the newer machines.

Chris

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Re: I'm going to disagree....
Posted by: Bob38
Date: January 30, 2019 11:01PM
Thanks guys. I appreciate the input. Being new to the art I’m sure more questions will follow.

Re: I'm going to disagree....
Posted by: IDXMonster
Date: January 31, 2019 07:44AM
Quote
Chris(SoCenWI)
Kevin,

Nope, I guess I was disagreeing that it was the halo that was made open screen conductive impossible, when it is iron itself. And I had to do my normal rant on how much worse the target ID is on the newer machines.

Chris

Understood! I always want to make sure I’m not reading too quickly or taking something out of context because one “wrong” setting equals one huge disaster in some places! I’m no stranger to huge disasters!:lol:

Re: Why is TTF the best option for iron laden sites
Posted by: Trashfinder
Date: February 01, 2019 06:27AM
You can open the screen in either tonal mode to combat null. Simply you are telling the machine what direction ( x,y) you want to base your tones on. The x direction is based on the CO number, the y direction is based on the FE number and where it lies on the number line for either x or y. The response on either will be based on what you have accepted and rejected on the disc screen. All it boils down to is this,,, do you want your tonal ID based on the FE number or the CO number. Keep this in mind, take say a silver quarter, lay it on the ground and put a nail on either side in the x axis direction. Open your disc screen on the FE line ( the y axis) down to around 30 ish, just enough to eliminate nails. Then slowly sweep your coil over the target and you will get a good tone in conduct. What you will notice is the Fe number has dropped to probably something like this 26-30 ish, but your CO number will be pretty solid on 45-47 ish. What you look for is a solid Co number to give an indication of possible target. The key to hunting in iron is not Ferrous tones versus Conduct tones , but rather hunting very slowly and not having a skewed target ID discriminated out, because that is what iron near a good target will do to any machine not just fbs. Having your machine in High trash is key as well , because in low the machine will just simply lock onto the strongest target. In High trash the machine will lock onto the strongest Accepted target. Run fast on as well gives your machine a better chance to recover on targets that are close together.

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Re: Why is TTF the best option for iron laden sites
Posted by: Bob38
Date: February 01, 2019 09:23AM
Trashfinder

One of the main reasons I have an Etrac is from what I read, it seems to be made for these situations. Having a Co and FE number instead of one combined number (like other detectors) gives the operator the ability to use his experience and brain. I currently have a mostly open screen and don't mind hearing the iron. Telling myself to slow down is something I continue to work on and takes concentration, but I will get there. I hunt with a friend that refuses to hunt in the trash due to the constant null and will move to a cleaner area. His ancient machine (:tesoro:) and refusal to update to newer faster equipment limit him severely. He doesn't believe what I'm telling him and when I get better at TTF I WILL SLAY HIM! :stretcher:


I have two sites I will revisit this weekend that has lived in my iron-infested nightmares, but has very good promise. If good targets are deep, I should be able to show something for it.

Thanks for the explanation

Wish me luck...........I'm going in :yo:

Re: Why is TTF the best option for iron laden sites
Posted by: Trashfinder
Date: February 02, 2019 02:54PM
Bob,, i have about 3.5 hours now on the Mars lion 7 inch dd coil. I am doing well in a couple of pounded spots. I am running the basic trashy park disc pattern, but i have the FE line open to 23. Needs to be a bit lower to not leave stuff behind, but at 23 you will still find good stuff but not dig a ton of iron. I am running mine like this. Deep on, Fast off, neutral ground, multi conduct, either normal or pitch hold, high trash. The reason i am having success is sweep speed. It takes me about 3.5 seconds to make a sweep, if you swing the coil like most others do single freq machines you are messing up. I cannot stress you have to go slow. If you get that sweet tone then investigate it by going in a circle while warbling the coil. If the tone stays sweet, then dig. For a coin hunter the Etrac is hard to beat except maybe someone with a CTX. And i am not saying the coil is better than another small coil , but i do like it.




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