TESORO GOLDEN SABRE

[Ultimate_Haze]

brrrrr

Hummmm.
Nothing new.........
Only finaly one nice picture of how the coil is wired.
Here is a question.I have made 5 coils 31cm.All is ok inductance,resistance...
But depth is poor.No meter what I try,how I null,even 30sm depth is not shore for large coin.Compared with other results here...Sheeee
So I am wondering isn't there a mistake that I have made while soldering.
Voltages are V+ 7,93 V-6,25.Is this ok?
In rx stage there is little pick in V- its 6,36.
So now I will try just 27.To make shore that device is ok.

This last version is realy silent.And audio is now stronger!I use 32ohm speaker.Because here 16ohm can't be found.

[Qiaozhi]

Whot do you think about vlf with more power.Simply increse voltage on tx cicuit,biger coil,nulling..Sombody try sothing like that?Can that pair some PI detector??

Regards!

Whenever anyone wants to increase depth in a metal detector they usually think about boosting the TX power first. However, it soon becomes clear that this is not the solution. The signal received from the target falls off inversely with distance from the coil according to the 6th power. In simple terms this means that you would need to increase the TX power by 64 times to double the depth. Even doubling the power will give a fractional increase in depth, but causes many other problems. For example, saturation of the ground matrix, and overloading at the input stage. You can get much better performance by improving the RX front-end.

[miki73]

Whot do you think about vlf with more power.Simply increse voltage on tx cicuit,biger coil,nulling..Sombody try sothing like that?Can that pair some PI detector??

Regards!

[Max]

Dear Ivco Max Qiaozh
with warm greeting
could you please tell me the deepest metal detector for
1-coinshooting
2-prospecting
3-treasure hunting

best regards

Hi,
I agree with Qiaozhi, if need reliable disc and depth you need Nexus or similar (though there aren't very similar to it) VLF md... much powerful TX stage etc
Sure cost is a big issue... thousands UK pounds, thousands euros, thousands US dollars! But you know the quality has always big prices.

A good alternative could be e.g. Minelab old models like Relic Hawk... Ivconic could tell you why if don't read posts about it: can find on e.g. ebay as second hand maybe for 500 USD or less.

Then, I would not suggest Nexus or any other VLF kind for "treasures": let me explain... sure any good VLF will detect big stuff at e.g. 40-50cm underground, no big deal if e.g. you have a big gold plate of say 50cm diameter there at 50cm depth... even stupid mds can catch that.

The problem is instead when:
1. the treasure is made of e.g. many coins (hundreds or more) at say 1m range... and each coin is "rusted" (don't happens to gold coins but silver yes, bronze yes etc) in that case you could pass over with VLF md and must have luck... the oxides make eddy currents propagation less effective and a VLF md is NOT reliable at 1m range even with big number of coins (many metallic separate objects): though treasures WERE found this way it's matter of luck most of the times when you have to do with >1m depth.
2. the treasure is a big object or objects (e.g. size of liters bottles) but at big depth of many meters, in that case the VLF on meters depths are totally uneffective... you can sweep over a car at 5m depth and read nothing at VLF, not a beep!

In that "special" cases you could consider the use of depth PIs: aren't discriminative mds but very powerful in the >1m scenario till many meters for very large stuff... You must consider the soil MUST be clean of big ferrous/trashy/dangerous stuff... e.g. unexploded bombs, antitank mines, scraps of iron etc. unless that better avoid that mds.

so my answer is

1. coinshooter : top VLF mds (like nexus)
2. prospecting : for general prospecting use like 1 top VLF
3. treasure hunting : if look for chambered treasures of deep stuff ... top depth PIs

Kind regards,
Max

[ivconic]

Dear Ivco
so what is the 10k trimmer?

Read my previous answer. Cant you read?

[Qiaozhi]

Dear Ivco Max Qiaozh
with warm greeting
could you please tell me the deepest metal detector for
1-coinshooting
2-prospecting
3-treasure hunting

best regards

If depth is what you're looking for, then you need to buy a Nexus Standard SE ->

http://www.nexusdetectors.com/NexusstandardSEmetaldetector.html

[metaldetector107]

deep MD

Dear Ivco Max Qiaozh
with warm greeting
could you please tell me the deepest metal detector for
1-coinshooting
2-prospecting
3-treasure hunting

best regards

[metaldetector107]

last TGSL

Dear Ivco
so what is the 10k trimmer?

[ivconic]

Dear Ivconic
after so many thanks
could you please tell me the value of RX capacitors,
also the trimmer 10k is instead of potemeter?
thanks again

It is 15nF (0.015) as noted on schematic. I reserved one place more on pcb just in case if want to fine adjust that capacitance by adding another in parallel. You may experiment and add 1nF in parallel with 15nF...or simillar value. Or 10nF and 4n7....etc..etc... You can find out some different value to improve performances there.
What 10K trimmer? For Sense ? It should be pot not trimmer. I just have bad habit to put trimmer footprints everywhere!

[metaldetector107]

last TGSL

Dear Ivconic
after so many thanks
could you please tell me the value of RX capacitors,
also the trimmer 10k is instead of potemeter?
thanks again

[Alexismex]

Ok Max i will check the revue

[Max]

Hello Ivconic and the forum here I post a photo from test in a french revue for analysis .
performance dans l'air : air test
performance dans le sol : soil test
Monnaie 25mm :coin 25 millimeter
Monnaie 45mm : coin 45mm
Capsule de bouteille: bottle cap

Hi,
which are coils employed for testing devices!? That's an important factor.

Kind regards,
Max

[Max]

I was speaking from experience.

Then all you guys use wrong components there !

Often I found that the silly things in fault searching are more related to pcb mistakes... or design mistakes... or simply that the pcb had e.g. a small scratch very narrow... can't see without lens or microscope.... then you see things are connected wrong way or are not connected at all!

Any accurancy one can use in selecting parts is unuseful is mistake is already at pcb level... that's my experience.

BTW I think just 1-2% of faults I found were related to wrong components selection... where instead 30% of faults are (to me) direct consequence of bad pcb design or pcb troubles (e.g. scratches on photoresist varnish already in the factory! )

Kind regards,
Max

[Alexismex]

Hello Ivconic and the forum here I post a photo from test in a french revue for analysis .
performance dans l'air : air test
performance dans le sol : soil test
Monnaie 25mm :coin 25 millimeter
Monnaie 45mm : coin 45mm
Capsule de bouteille: bottle cap

[simonbaker]

Firstly, the single-channel oscilloscope can be useful for simple fault finding, but for setting up the coil properly and to understand what is going on, you really need a two-channel.
Try following the instructions I gave you before:

If he has external trigger on his scope, can do even more to check phases.

Regards,

-SB