TESORO GOLDEN SABRE

[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 Ivco
so what is the 10k trimmer?

[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

[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/Nexuss...ldetector.html

[ivconic]

Dear Ivco
so what is the 10k trimmer?

Read my previous answer. Cant you read?

[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

[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!

[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.

[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]

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.

Your depth results seem reasonable. The French chart that was posted here is very optimistic. No doubt these results were obtained in an air test with all metal mode and maximum sensitivity. This is why MD manufacturers do not like to publish depth charts, as they are all somewhat subjective.
Max (I think) has some good results, but this was achieved after a lot of tweaking. If your homemade device compares to the commercial version, then I would be happy.

[Ultimate_Haze]

hi

Your depth results seem reasonable. The French chart that was posted here is very optimistic. No doubt these results were obtained in an air test with all metal mode and maximum sensitivity. This is why MD manufacturers do not like to publish depth charts, as they are all somewhat subjective.
Max (I think) has some good results, but this was achieved after a lot of tweaking. If your homemade device compares to the commercial version, then I would be happy.

So you are maybe right.
Molzar have the original device maybe he can comare with handmade.
I dont own original TGS.
I can compare with TRS but wont be fare due to diferent coil size.
The thing that worry me is that Max gived over 40 cm with same coil for large coin.
And my results are poor with this last device and this larger coil.Near 30cm.
Hum....
I now its all about the coil and thuning but there is still something I miss here.
Don't wanna discus nexus here its other stuff.
How you think that RX can be optimized in this design?
Please share your ideas.

[Qiaozhi]

The thing that worry me is that Max gived over 40 cm with same coil for large coin.

You will have to ask Max about that.
40cm is nearly 16", which is a better claim than made by Nexus!
You should really compare to the commercial model.

[ivconic]

Huh, that reminds me on my experiences. I also tried to make good 32cm coil without success. I achieved extra good performances with 27cm coil....but with 32cm not so good!? How come? First i think it is about wire. I used same wire as on 27cm. Second...i have my doubts about TGS. Dont know how to explain..but it is optimised for cetain coil diammeters. Looks like... at least. Very good performances can be achieved with smaller coil also...let's say 20cm and 24cm diammeters...27 of course...but 32cm...hmmm.. i havent succeed so far. And i gave up already.
Also i agree with Quiaozhi, chart results looks rather optimistic...or those were achieved only in air. If those represent air distances, than are ok. But if those represent depths in soil...than i can only say WOW!

Speaking of coil sizes....up from recently i am happy owner of Musketeer. It came with 18cm coil (TS800). But...also i managed to get 36cm,39cm and 45cm DD Excelerator coils for it. So....
What to say? Same thing - i am not thrilled with what i gained with larger coils, comparing to what i gained with smallest one. Smallest one, 18cm is working over any expectations! Yet deepest is 36cm coil, but considering fact it is double size than smallest one...than those results i gained with it are not to be thrilled about.
Eventuall comparing chart of results gained with all mentioned coils would show that 36cm coil is deepest (optimum), than 39cm on second place, than 45cm and last would be 18cm (but for sure deepest if coil size is only criteria).
But...also 18cm coil is absolute champion when comes to comfort, pinpointing and sensitivity on smallest items. Other hand 45cm coil is best for covering large area and going very fast forward. 36cm and 39cm are in the middle.
I can name now air results if any benefit from those:

* 18cm coil, 1e coin = 28cm in air,
* 36cm coil, 1e coin = 42cm in air,
* 39cm coil, 1e coin = 40cm in air,
* 45cm coil, 1e coin = 41cm in air .

* 18cm coil, cola can = 65cm in air,
* 36cm coil, cola can = 85cm in air,
* 39cm coil, cola can = 87cm in air,
* 45cm coil, cola can = 125cm in air.

So... you can easilly see and understand tendecies here.
Actually you can not expect huge depth increase on smaller and smallest items if using larger coil diammeters.
Rule of thumb is not the absolute rule here.
Larger coils are more suitable for locating larger objects and cover more area when swinging over soil.
Smaller coils are more suitable for detecting smallest objects and present best choice for accurate pinpointing.
I guess same thing is with TGS too.

[Ultimate_Haze]

That is very usefull info.
Can you post tgsl performance on same ithems with 27 DD?

[Qiaozhi]

Second...i have my doubts about TGS. Dont know how to explain..but it is optimised for cetain coil diammeters. Looks like... at least. Very good performances can be achieved with smaller coil also...let's say 20cm and 24cm diammeters...27 of course...but 32cm...hmmm.. i havent succeed so far. And i gave up already.

This might something to do with the relatively low power of the transmitter. Perhaps a more beefy TX would work better for large coils, although it would most likely make things worse for the smaller ones.