Tom - Disc 6 and the F75 LTD

I read your compilation thread for the original F75 and your recommendation for trying a disc 6 setting in monotone to unmask more non ferrous targets in heavy iron nail ground. Does this recommendation still hold true for the F75 LTD? Would it apply if operating in bP process? Also I have done some limited testing on square, iron nails I have collected and my F75 is not discriminating them out at disc 6. I am still getting a pretty solid monotone response on them. I have to go up to about disc 10 before the tone starts breaking up to clicks and pops. Would a disc 10 setting still be worthwhile to try for unmasking?

With the ltd 0-4

LowBoy

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I'm gonna guess that like disc 21 on the T2 disc 6 on the F75 handles the typical iron found at most sites. With the T2 I found that some sites required disc 22 to shut down the iron. The size and state of decay of the iron should determine the disc setting.

Are the nails reading iron or non-ferrous?

Tom



Edited 2 time(s). Last edit at 02/22/2010 02:05PM by Jackpine.

Yes, the LTD and a standard F75 with a Disc setting of '6' (only while in Monotone)....is exactly the same. What may differ.......is the iron decomposition status of YOUR area. This can be determined by placing the LTD in monotone.......and start changing your Disc settings (whilst sweeping coil in highly nail-infested dirt) and see where you can JUST BARELY Disc out the nails. This MUST be performed with nails in the ground. Air-tests does not work quite as well. Yes, air-tests......the Disc may need to be placed on Disc '10'...... but probably NOT THAT HIGH for nails in the ground.

I doubt you will be able to use Disc 0 - 4 whilst in monotone. These settings are reserved for 2, 3, 4 tone option(s). There has been one time where I was able to use a Disc '2' setting in monotone..........as the nails had ever so badly decomposed to a nearly 'gone' status. In this extenuating circumstance......unmasking performance was superb with a Disc '2' setting.......as compared to a Disc '6' setting.

Thanks for all replies. I was getting ferrous tone on the nails. I was testing the discrimination required to eliminate them in air. I will perform the test again at the nail infested site as suggested by Tom D.

So Tom are you saying on the LTD mono tone you can really only set dics on 6 but on a disc of 0-4 you need to be in 2-4 tone?

LowBoy

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Lawrenzo Wrote:
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> So Tom are you saying on the LTD mono tone you can
> really only set dics on 6 but on a disc of 0-4 you
> need to be in 2-4 tone?

I believe he is saying in nail, iron infested ground, disc 0-4 would not work well in monotone because you would be picking up the iron too well. You could not tell the difference in the sound of a non ferrous target co located with an iron target at that level of discrimination. There has to be enough discrimination of the iron to cause you to investigate closely any "sweet" sounding monotone response. If the iron discrimination level is so low that everything tends to sound good, you aren't accomplishing anything in monotone. Multi tones would be required at those levels of discrimination to separate good targets from bad.

Exactly!

How well does this setting work in Hot soil thats in the North part of Va.--Thanks

That's a good response dgc.

Is there any advantage of using monotone vs 4 tone in this bed of nails scenario? I'm not sure my ears could get enough data from monotone to vet out a "sweet" target from a ferrous target, whereas with 4 tones, I would tend to believe more audio data would prompt one to retrieve a keeper (but I could be wrong).

Cal_cobra Wrote:
-------------------------------------------------------
> That's a good response dgc.
>
> Is there any advantage of using monotone vs 4 tone
> in this bed of nails scenario? I'm not sure my
> ears could get enough data from monotone to vet
> out a "sweet" target from a ferrous target,
> whereas with 4 tones, I would tend to believe more
> audio data would prompt one to retrieve a keeper
> (but I could be wrong).

Cal,

According to Tom's writeup on this subject, multitone use at a disc 6 setting could cause you to miss some masked non-ferrous targets. If the combination of a non-ferrous target co-located with a ferrous target registers anywhere between 6-15, you will get an iron low tone (grunt) and will likely pass up the target. Depending on the amount and location of iron in this situation a reading between 6-15 could be very likely. So monotone is the way to go to give you the best shot at not missing anything. Even this setup is not perfect. Large pieces of iron can completely mask non-ferrous targets and even sound off as good targets themselves, but Tom's disc 6 setup gives you the best shot.

By the way Tom, if you are still following this thread, you were right. When I tried disc 6 in the nail infested ground, the F75 LTD was discriminating the nails to clicks and pops audio pretty well so I don't have to run at a higher disc setting as my earlier post about my "in air" tests led me to believe

Glad this helped.

Just to be clear "monotone" is a different tone then the iron grunt or no?

Brian

I think there is a misconception about small iron disc settings with people that have not spent time with single tone detectors. Even tho disc 6 is well below the F75's highest iron number it does silence the majority of iron. Beyond that it comes down to the audio length of the signals that come thru. What I mean by that is that coins give coin sized audio responses and larger targets sound bigger. Back when I used the 1236X2 I could tell a coin almost every time because of this. There are other techniques that can be used to determine the size of a target such as raising the coil and noting where the target response drops out which eliminates digging most of the bigger iron.

Small iron disc works best with fast reponse/fast recovery detectors. There are detectors that are designed to report the peak signal strength of a target. Since they "wait a bit" before putting thru the audio response you don't get the full benefit of low disc settings.

I hope my "roundabout" answer helps.

To add a bit more.. In most cases targets audible at small iron reject settings that are missed by the multi-tone options because of the iron grunt do read non-ferrous. Tom D's amazing dime recovery excepted.

Tom



Edited 1 time(s). Last edit at 02/25/2010 10:36AM by Jackpine.

Thanks Tom, that makes sense.

I'll have to do some testing with this, I don't get to hunt a lot of old nail infested sites, but I do have a site in mind to test this and the 4 tone/zero disc settings at to see how they work.

Thanks again,
Brian

When you invoke monotone.....the detector produces only one tone for any/all type of metal objects (as to be expected)...and this tone is a MID_TONE.