TESORO GOLDEN SABRE

[WM6]

[quote/]I move up and down,it seems got more deeps,
and i make the coin upright.it got more deeps too.
.[/quote]

[WM6]

Hi Ivconic and Max,
How to test the TGS sense?
I move up and down,it seems got more deeps,
and i make the coin upright.it got more deeps too.
this picture is my test result:
[ATTACH]4521[/ATTACH]
how do you test the machine?
Kind regards.

Good observations zzy. Results of measurement depends on geometry of targets position in soil and the way of coil motion too. The same in the air test. It depend on how thick lines of EM force decline to main target (e.g. coin) surface. On principle movement of test coin in air imitate coil movement against soil surface, mean that have to be parallel to coils down side surface. But fundamentally every measurement is correct by self and at the same time not correct in comparison to other measurement, when, because of different applied propagation, is not comparable. So, on measurement is very important to give participant all measurement procedure data to overcome subjectivity and to assure that results are comparable (if this is important of course - if not, measurement speaking for itself).

[zzy]

test

Hi Ivconic and Max,
How to test the TGS sense?
I move up and down,it seems got more deeps,
and i make the coin upright.it got more deeps too.
this picture is my test result:


how do you test the machine?

Kind regards.

[ivconic]

"..It is interesting to measure changing of EM field around coil putted on soil not only in air..."

This is crucial! Once for all,finally to establish losts at soil surface. Losts or attenutaion - call it anyway you want.

[WM6]

Instead telescope antenna on Zahori, i put small 2cm coil taken from old 5.25" floppy (step motor in in has several coil segments - small and cute for this job)...

Very fancy idea, ivconic, you are boss, you are Mr. O'Coil!!!

One can measure this by an old long known versatile amateur radio instrument, so called grid dip meter (or dip meter, or GDO). Very simple to build, one fet (or planar one, even vacuum tube) transistor, variable C, pot and small coil as you taken from step motor. There are enough schematic to find on WWW. For MD purposes inductivity of used coil have to be in limits of common L of MD coils.

Here some history and ideas to build GDO:

http://www.noding.com/la8ak/m11.htm

There are Q-meter and other construction ideas too.

It is interesting to measure changing of EM field around coil putted on soil not only in air.

[zzy]

Thanks

Hi Ivconic and Max,
Very thankful for your help,I found the reason: I'am too stupid ,I forgot connect the RX to gnd,Now the coil null at 8mv VPP.but the sense is no increase.the machine will not beep if i touch the cable. I fix cables to pole using some tape,it's very good.
Thanks for Ivconic and Max support!
Now I detect 10eur-cents from 23cm in all metal, on air.But on notch mod it's only detect a gold ring at 11cm.

[Max]

Hi Ivconic,Now,I null the coil at 17mv VPP,the sense is good.
but I have another question,please help me.
Just like you had said i use two separate coaxials cable. the question is
if i tuch the cable,or bend the cable,the machine will beep.it make me crazy.

Regards and thanks for your support.
Here is my coil and cable.[ATTACH][ATTACH][ATTACH]4517[/ATTACH][/ATTACH][/ATTACH]

Hi,
I think you have to fix cables to pole using some tape or other stuff plastic made better.

If you leave cables free to move you'll become crazy about false signals.

Also use good quality wires/cables (e.g. some computer cables are good for this) with low capacitance... cause you don't want too extra capacitance added to the oscillator / rx sections... also some audio stuff is good for this.

Remember... we are using extremely hi amplification chain in TGS so... any small change due to movements etc will make it sound: make device totally solid/rigid stuff.

Kind regards,
Max

[Max]

Yes, it started as trial coil and turned to very serious ideas to adopt this as main type of coil for TGSL....
I didnt expected such good results at all!?
Most important fact is that this omega coil is indeed stabile as a rock.
I will repeat, it is very hard to balance it. Much harder than usuall dd coils.
But once it is nulled, well...well...
It think it will beat DD coil in depth also.
Not to mention narrowed area of detection.Pinpointing is 100% accurate with it. Actually area of detection is exact area covered by RX coil, no more, no less. In the past i made 2-3 omega coils for that md 3007, which was nomotion metal detector, poor performances comparing to TGSL. I didnt payed much of attention on those omega coils at the time. Those were made just to test detector, since original coil came with it was omega coil. I made few copies of md 3007 and logically made also coils for those by copying original coil. So i burried in my mind those as not so serious coils.
Now, i am equiped with more experience and payed a lot of attention on balancing and remaining exact inductances needed by TGSL.
I think i will propbably switch to this kind of coils in future. Yes next would be larger omega coil, at least 25-27cm. Huh, it will need further calculations and experiments to find exact number of turns for coils.
This time 0.25mm wire is used. On larger coil i guess 0.3mm would be more suitable to be used.
We will see...

Hi Ivconic,
thanks for the good news about it! I'd like to build one too.... larger version say from 25 to 27cm outer diameter.

I think you'll get really good results with larger one than 21cm trial coil.

Yes... the pinpointing ability of these coils is really cool feature, also if you lose about widescan action on these. I like this kind of coil cause I see it easy to shield and play about nulling... even more than DD.

Sure, critical nulling is always hard to get in few time... but I think this model is really easy compared to e.g. concentric-coplanar... where you have to cut wires... make lose loops and other dirty tricks to get them work with right null.

I'm awaiting for some wire too (0.25mm/30AWG) to build some new coil and think I will play too with omega in next weeks. I'm doing other stuff (digital) now and it's just an idea at the moment... but in future I'd like having one omega too for my TGS. I see it well on it.

I've also to check again TGSL circuit (I've buried it under some pile of other circuits) and start again with testing when got more spare time.

Anyway, thanks again for your efforts and goodwill in this stuff... I really appreciate much informations you provide.

Best regards,
Max

[ivconic]

Oh, another idea - walkman with extracted head (on longer cable) can be used to hear em field in speaker, also...

[ivconic]

Instead telescope antenna on Zahori, i put small 2cm coil taken from old 5.25" floppy (step motor in in has several coil segments - small and cute for this job)...

[ivconic]

Yes, ivconic it would be interesting to present field shapes of different coil diameter alone. At the same time we can not forget that construction of overlapping coils (DD, OO, Omega) considerable reduce Q of both coils. Catch is to find not so overlapping coil, but still capable to tunning/nulling and RX diameter as big as possible. Maybe OO disturb Q of both coil least of all in account of unpractical shape.

Due fact i dont have another way to test this, i used small em probe to locate em field arround coil. Pretty rough method, but gives me also some "picture" about em field shape and size. And i noticed pretty sharp pike look like eliptical shape arround small 20cm coil.On other hand "soft" and more look like circle shape arround 32cm coil. And size of smaller shape was almost the same as at larger coil. Size or reach of em. Yes this is not quite accurate method, but right now i dont have better method. Zahori can be adjuste at very low sense to do this job - em field probe. Only good imagination is needed to picture em shape and nothing else...

[ivconic]

Using CRT holder for housing - nice! Really do have look and shape!

[ivconic]

Hi Ivconic,Now,I null the coil at 17mv VPP,the sense is good.
but I have another question,please help me.
Just like you had said i use two separate coaxials cable. the question is
if i tuch the cable,or bend the cable,the machine will beep.it make me crazy.

Regards and thanks for your support.
Here is my coil and cable.

Shouldn't!? Try to adjust GEB trimmer a bit. RX is connected to gnd in coil but not on pcb. Both Al foils are connected togather as well as both cable shields - in coil, but separatelly at pcb, without RX on gnd (as told before).

[WM6]

May be I should post the comprehensive results on the coil section to not disturbing the other contributors here. Please make a starting thread and I will post every step consequently. So at the and, we can make a prototype of nulled "Omega-concentric" coil. (How should we name this type of coil?)
Aziz

Agre Aziz. There is new "cComega" thread on coil section. You are welcome! Others too. Suggest to publish by ivconic presented diameter related coil Em field presentation in the same thread. This tread become extensive.

[zzy]

Hi Ivconic,Now,I null the coil at 17mv VPP,the sense is good.
but I have another question,please help me.
Just like you had said i use two separate coaxials cable. the question is
if i tuch the cable,or bend the cable,the machine will beep.it make me crazy.

Regards and thanks for your support.
Here is my coil and cable.[ATTACH][ATTACH][/ATTACH][/ATTACH]