TESORO GOLDEN SABRE

[detectoman]

question for ivconic and max:

have good function tgsl underwater?
------------------ in proximity other md, e.g interferences?
-------------------- hot rocks?
-------------------- in exteme conditions hot or cold e.g what stability have
-------------------- ! because xlt white have faults after 1/2 hour these is work
-------------------- is good discrimination tgsl on iron one x one metre objet? to 30 cms depth?
------------ resistence tgsl in porcente humidity no risk of short circuit? eg burn
thanks for attention
detectoman

[ivconic]

question for ivconic and max:

have good function tgsl underwater?
------------------ in proximity other md, e.g interferences?
-------------------- hot rocks?
-------------------- in exteme conditions hot or cold e.g what stability have
-------------------- ! because xlt white have faults after 1/2 hour these is work
-------------------- is good discrimination tgsl on iron one x one metre objet? to 30 cms depth?
------------ resistence tgsl in porcente humidity no risk of short circuit? eg burn
thanks for attention
detectoman

Underwater...? I never tested it!
Interferences.....depends what kind of those? For example, in my workshop there are some sources of noise,interferences...TGS showed absolute imunity on those! Superb!
Hot rock....very mum "cracks" can appear on those. Not disturbing much, at all! Again good!

Temperature.... i am using my TGS for over 3 months under various temperature conditions...No problems! I noticed slightly better perfomances when higher moisture...for example; early in the morning! But on the same field i came early in the morning, when sun rises and temperature rises also, soil start to dry; i noticed some unstabillity than? Ocassionall beeps!?
But if i come on the same field, in the middle of the day...than TGS works stabile....

Discrimination.....is good as it can be. Smaller iron objects disriminate perfectly - absolute. Large iron masses cant discriminate well, but nevr mind, audio on those is recogniseable - different than on "coloured" items...so it is easy to distinguish it..

Last question....well it depends on coil housing mostly. If you put it in a "pocky" enclosure...for sure it will suffer...But if you put it in closed, good isolated housing, than no problems at all! Same with coil...

Damn! I am still here....
I just cant give off...Rare oportunity...many members on same place at same time! Carl, Carl...! That's why i suggested chat mode here!

[ivconic]

Like somebody blowed whistle!!! Everybody left!?
I am going too....
Fade out....

[tiktak]

Hi,

Hi Max,
I am using DT9205A multimeter, it have 200 mV range in AC.And like you say 1M resistor and 15N capacitator paralel and conected to RX.And look for .000!
So If my problem is nulling then............

I have a few more questions for You and Ivconic:

1.Have you reach 35 cm for 1 denar in air with 1M modification of not?

2.When you wind coils you start winding from bottom and you moove up without turning back or you make few layers?

3.I can find KA and TEA 2262 can I use this for TLC2262 or they are different things?

Thanks

[tiktak]

Hi,

I have made the first PCB with NOTCH.
Why you remoove NOTCH section Ivconic?

[Max]

Hello Ivica and frends

No problem for showing the goldy pcb. Made it together with Nakki.
Here the latest version.... but there is still on high sens sometimes erretic noise.
Can it be that it is 50-60HZ ?? Is it a pcb design error?

Ap

Hi Ap.Berg,
thanks again for your work (and thanks Nakki too) I found it really cool.

The picture you posted also seems a very nice work about assembly of it.
Very good, congratulations.

About noise... well... yes if you have some noise source near it will pick up some and you'll ear in speaker... but it's rare if you haven't e.g. fluorescent lamps just over coil... and the like... e.g. a TV set on just at few distance etc

Personally I think that TGS with good shielded coil if at least 1 order of magnitude better on this than any PI on the workbench... they have all serious problems with 50-60 noise. VLF suffer more of TV and other noise sources at 10s KHz (like electronic ballasts etc flyback circuits...).

I think that the noise we hear sometimes... when e.g. we rotate GEB trimmer to particular position during tuning is related to circuit problems...and coils are ok.

I've tested all coils I have suitable (9x8'' original, 8'' opencenter, 8'' DD, DD22cm, DD255x137, OO12cm...) all give that noise sometimes at certain trimpot positions... I noticed that using a ferrite toroid core... trying to null effect of it with various coils and got noise quite easy when I pass the sensitivity area for ferrite... just 1° turn more on trimpot and I get noise at max sens.

I strongly think is some kind of intermodulation inside the circuit between osc freq and others... and probably comparators are much involved in this cause they commutate at that frequencies.

Also , as you can see from simulations, the only oscillator produce already some intermodulation cause of feedback part.

So, if we want avoid this we have to find the sources of that problem that's all about purity of signal we have through the circuit.

Another thing that I've noticed is that when I touch with finger the aluminum case of disc pot noise disappears... same happens just nearing the finger to the geb trimpot... so sure there are problems that show up at particular phase shifts...and that could be related to intermodulation... cause at some phase shifts the effects could subtract one each other ... and at others they could sum giving that bleeping.

I've also connected the aluminium case of disc pot to gnd but that doesn't solve problem... works just with finger !

What to say... it's a real mistery !

Best regards,
Max

[tiktak]

Max NICE coil!

[Max]

question for ivconic and max:

have good function tgsl underwater?
------------------ in proximity other md, e.g interferences?
-------------------- hot rocks?
-------------------- in exteme conditions hot or cold e.g what stability have
-------------------- ! because xlt white have faults after 1/2 hour these is work
-------------------- is good discrimination tgsl on iron one x one metre objet? to 30 cms depth?
------------ resistence tgsl in porcente humidity no risk of short circuit? eg burn
thanks for attention
detectoman

Hi,
Underwater ? No you cannot use it.... maybe you can use on wet sand e.g. of rivers (not in salt water environments)

Interference ... as other detectors ... I mean if you have another VLF running at 14KHz at less than 1meter that would be a real problem... otherwise not...for PI near you need at least 10-15meters far away... otherwise it will pick up the PI TX signal very easy.
On workbench it's about totally immune to "house" noise... apart extreme cases I wrote in a post above (flyback near, tv sets on, fluo lamps... and the like).

Hot rocks are a problem for TGS if they are very large and with much minerals of iron inside. Small things like a cigarette box to a VHS box or similar have no effect on it, same for pottery stuff , bricks... it's ok if you set GEB far middle.

Temperature has no great effect on it from 10 to 35°C... that's cause the zener voltage change really a few with temperature... and all the rest is rock soild... even if you heat up some stuff on PCB intentionally it remains quiet ! Only noise source is from internal intermodulations and part noise that you can minimize using special parts.

You could have problems at temperature changes (e.g. from cold early morning to warm morning say... when rise is of 10°C or more in less than 2hours, so >5°C/h) and for temperatures above 40-45°C cause of the increase number of minority carriers and the like.

Discrimination is perfect against iron (pure) on small items like coins. When you have large iron stuff e.g. poles or large e.g. iron plate (>30cm diameter) you'll detect at when the thing will start distorting too much the magnetic field... for the pole (e.g. height 2meters, diameter 6cm) also from 40-50cm... for the plate at less distance.... you can detect e.g. an hammer in disc just if it's big and when at few mm or touching the coil !

I think it will work till 70% humidity very good... and things could be worse only at >85%. I've tested at 90% humidity just one day ...and apart the stress of digging holes at 33°C 90% humidity I found it worked good... just some chatter sound from time to time... nothing else. I think that's impossible to damage TGS even at 100% humidity cause it doesn't use lot of power or hi-voltage... so it's safe as using an MP3 player in your kitchen... it can work there for years without problems ! That's what I think.

Best regards,
Max

[Max]

Regarding this simulation stuff you guys are doing with the TX osc:
One important thing you'll eventually come across (if you just randomly swap component values to make improvements) is that you'll end up with a circuit that performs well in simulation but doesn't work in practice. My advice is - before you build anything, run a Monte Carlo analysis and a temperature sweep. Can LTspice do this?
If you modify this amplitude-stabilized configuration without running an MC analysis, you could build 10, and only 5 might work - if you're lucky.

By the way - nice coil Max!

Hi,
yes it does montecarlo analysis ... next time I'll use it before making mods or circuits to be sure or changes involved. Thanks.

About coil... yes... to be homemade with strange things it looks not too bad.
But what I like more is weight : 350gr total is very relaxing for arm... without wasting performances.

I've used the surfboard approach... polystyrene bubbles to keep weight low and epoxy to reinforce it and polypropilene bottom... and it works pretty cool.

The little work was on cutting polystyrene foils and I've made and hot cutter using NiChrome-wire and a PWMedd Mosfet... like in model airplanes starters... and it cut that like a laser

Best regards,
Max

[Max]

Hi Max,
I am using DT9205A multimeter, it have 200 mV range in AC.And like you say 1M resistor and 15N capacitator paralel and conected to RX.And look for .000!
So If my problem is nulling then............

I have a few more questions for You and Ivconic:

1.Have you reach 35 cm for 1 denar in air with 1M modification of not?

2.When you wind coils you start winding from bottom and you moove up without turning back or you make few layers?

3.I can find KA and TEA 2262 can I use this for TLC2262 or they are different things?

Thanks

Hi tiktak,
you have to use 1K resistor not 1M... and of course the 15nF cap.

You can null using multimeter (I can too, I've tested and works cool) but be sure you gain exactly 0.0 mV not 0.1mV or something more or e.g. -0.1 ...cause otherwise you have maybe 20mVpp or more on coil and that's not so good.

1. without 1M mod for audio I get signal too but sound is weaker than with it... so I get e.g. 1eur coin at 34cm about loud without 1M resistor, with it I get with loud sound from 35-36cm too, that's about top of the range for it. That's more important with smaller stuff like small 1eur-cent coins , with 1M I get loud sound where I just cannot hear sound on speaker without cause is very weak. VERY WEAK BUT THERE IS ALWAYS... I mean if I use headphones I hear easy all small sounds I have without the 1M resistor.

2. I wound totally coil from start to finish from bottom (wood plane), and don't use separate layers... if you watch at my posted picture you will see that thing.

3. NO. KA and TEA2262 are ic for SMPS used in TVs and the like... they aren't op. amps. you have to find TLC2262 or you can try with TS27M2 for instance.

Best regards,
Max

[Max]

I have made the first PCB with NOTCH.
Why you remoove NOTCH section Ivconic?

Hi,
can I answer ?

Cause he don't need notch, cause notch section waste 40% of energy if you don't need it, cause you have to buy and mount components and make larger board, you need a larger case, you carry more weight, you need another pot and 2 switches more...and much of luck with comparators... and if you don't need why complicate life ?

Another issue is that notch could also introduce more noise there YES!

I've the original board with it... and I'm start thinking that maybe I need build goldy or the Vladimir's one cause of the reasons of above... but I'm happy with original board... cause I've found some workarounds like the TLC2262 to solve some big problems... and occasionally I've used notch to cancel foil in one infested site...and works cool for this...well you will miss also some gold... but who cares of gold ?

Best regards,
Max

[ivconic]

Quiaozhi while mentioned Monte Carlo analysis...? Its better to use Daytona analysis instead...!!! Shheeeeshhh!!! Or Le Mans analysis even better...!?

BS

[ivconic]

TikTak i dont need notch, that's why i omited it...
Why the hell nobody reads all the posts from this sad forum?????
How many times simillar questions...???

[ivconic]

So i listened Quiaozhi's suggestions...i played arround KOP's hysterezis....not even close! Same behavior...!

I decided to take shots from some oscilograms....Yes i know; my osci. is obsolete and funny...yet here are some shots...
Only thing is not clear to me is osci at 1.pin of LF353?????

[ivconic]

Max can you scope your LF353 pin 1. and post it here?

Something is "misty" here???