IGSL

[ivconic]

Hi Ivica

Welcome Back
please give information about a good performance coil for this MD.
as you mentioned above like TGSL but write it again caus ein TGSL many every people suggest a different coil !
coil diameters , number of turns and wire thickness , resistance ...

best regards

I always make coil described here:

http://www.geotech1.com/forums/showthread.php?t=15710

Others might be gained good results with different coil data, i can't tell. I always make one and the same coil with same data: 6mH and 6.5mH. TGS/TGSL can be pretty tolerant on coil inductances, so those can vary from 5.8mH to 6.1mH for TX and 6.3mH to 6.6mH for RX. More important is coil balancing, shielding and wiring. Already everything described, so many times in the past.

[Great_Alex]

Hi Ivica

Welcome Back
please give information about a good performance coil for this MD.
as you mentioned above like TGSL but write it again caus ein TGSL many every people suggest a different coil !
coil diameters , number of turns and wire thickness , resistance ...

best regards

[simonbaker]

Re IGSL, consider:

Each channel is really half a notch.

The normal channel rejects everything below the level, accepts above.

So it is a notch that is missing the top cutoff control.

The "iron" channel, if I understand correctly, rejects everything above the disc level.

So it is a notch that is missing the bottom cutoff control.

I think a design that would be clear to the user would be to have two identical full "notch" channels. Each channel simply makes a different tone. The labeling would be same except labeled channel1, channel2.

There would be no confusion -- just set the notch for each channel. You can always set the bottom or top cutoff to max or min to get conventional discrimination.

It would also allow you to hear different tones for gold and silver for example if you wanted.

Of course it means even more channels -- two entire TGS circuits! Lots of parts.

------------------------------------

Ok, how about this --

Back to the IGSL -

Why not make it (or interpret it) as a single channel notch machine with a special twist. When the notch is in "reject" mode, the targets below the notch have one tone, and the targets above the notch have a different tone.

With Ivconic's circuit, the notch levels can overlap (i.e. crossover) -- but is that necessary??? Maybe useful, not sure.

Users are probably familiar with concept of notch and use of pots.

So in IGSL as currently designed, DISC1 knob is "upper notch level", DISC2 knob (non-ferrous reject) is "lower notch level", and the mode is always "reject".

Just another way to look at it.

-SB

[ivconic]

Hi Ivconic, your posts are always interesting and informative! This new design looks promising. Would it be helpful in i.d. of steel bottlecaps? Would additional controls make it additionally confusing to operate in the field?

Whenever operator hear both frequencies at the same time in speaker - there is huge chance that it was bad target detected. Horsehoe, bottle caps etc..etc.. Only when one frequency goes one after another - it would be situation where ferrous material is placed nearby nonferrous and vice versa. Actually, there are not much controls to manipulate much with. There will be 2 Sens controls ( Nonferrous Sense (Disc Sense) and Ferrous Sense (Iron Sense) ) and two "Disc" controls ( real Disc and other one that conditionally can be named "Disc", on Fe block). First one, Disc, at nonferrous block will act as conventional Disc control, by which operator can adjust level of ferrous rejection. Second one, at ferrous block will be most of the time adjusted fully anticlockwise ("minimum") and in that position; second, FE block, will fully reject nonferrous alloys. Only in situation where operator wants to separate some nonferrous alloys with different audio pitch - he can readjust this knob clockwise, up to desired level.
So.. there will be only 4 knobs on front panel.
I was thinking how to name those controls. Their internal functions are pretty clear.. but i had troubles how to name those to be closest to common operators logic and mentality.
So it better be left to each operator personally to choose most suitable name for that control.
My offer is: Disc Sens and Iron Sens for sensitivity controls and Disc for disc knob at first block.... but how to name second disc at second block? How to name it shortly? Most suitable name would be as on schematic - Nonferrous rejection level. But it is to long name to be placed on small front panel.
Aside that; i don't think that there are to much controls, only 4 and all are straightforward and easy to understand.
Various combinations of those 4 controls is quite another story. It will need a bit of experimenting and practice to establish most desirable setup for certain given condition. It is up to operator to establish that and choose what suits his needs at that exact moment.

[Wiltran]

ISGL

Hi Ivconic, your posts are always interesting and informative! This new design looks promising. Would it be helpful in i.d. of steel bottlecaps? Would additional controls make it additionally confusing to operate in the field?

[Stefano]

I' m glad to join these friends in saying "Welcome back" to ivconic

[nejdet]

Welcome Ivconic.

[nakky]

Welcome back Ivconic.



Grt Nakky

[eduardo1979]

Igsl

Welcome Ivconic. IGSL Congratulations, good job.

[simonbaker]

Nice idea! Thanks for sharing hard work, especially PCB! Glad you are still working on interesting ideas and making them available.

Regards,

-SB

[ivconic]

another thing..is this project uses a standard DD coil like in project of tgsl or coil is bit different?

best regards

Coils supposed to be the same as for TGS/TGSL. No changes.

[ivconic]

Hello Ivconic!

Nice to hear from you. Very nice design. The feature that interests are the dual channels, much like the Nautilus by Tyndall.

One strong feature of the Nautilus line is one that might not be obvious right away, and I would be interested in hearing from you if you notice this same behavior.

With the Nautilus, you have two channels, one AM and the other DISC. The Nautilus has no target ID but the user can get a general indication of conductivity by listening to the intensity and timing of both signals.

For example, if the disc channel is louder and rings in about the same time as the AM channel, then it is likely a high conductor. If the AM channel is louder and rings in slightly before the DISC channel, then it is likely a low conductor.

ALSO, it is much more difficult to be fooled by large iron with this machine because the AM channel will come in "booming" and long before the DISC channel.

While the TGSL does not have any modulation to the signal intensity, you may still notice a difference in the timing of both signals, which may be useful!

Now I realize from reading your post that the IGSL is sort of a "reverse" from this, but still might be a useful feature if you can tune yours this way.

I had Nautilus on my mind when realizing this idea. You have good observation on similarities and differences between those two approaches. I agree.

[ivconic]

+1 PaullyG.

ivconics posts i always read with lot of interest.
Welcome back! We need guys like you.


Very interesting design. Im interested in making this beast.
So it means three souind freq? ferros, non ferros and combination of both?

Exactly! With addition that operator can affect "third" audio (both freqs) by adjusting Sens potentiometers separately.

[taliesin]

one to watch this

you is a legend

[lunamay]

another thing..is this project uses a standard DD coil like in project of tgsl or coil is bit different?

best regards