TESORO GOLDEN SABRE

[mostafalesnar91]

I understand what works. But 358 is a very noisy op amp. Replacing with another should improve the performance of the device. I'll try to do it at home

these two must be replaced???
i can using ic 258 instead 358??

[mostafalesnar91]

That is the GB pot.




It works...

you sure??
until now, i used bottom pot to balance my device!!
both are GB pot????

[kt315]

these two must be replaced???
i can using ic 258 instead 358??

write full coding. LM LF??? what do you mean??????

[mostafalesnar91]

write full coding. LM LF??? what do you mean??????

LM258 instead lm358
my device is not balanced at all!!
it always makes noise with the movement the loop,even when ferrite not sensed!!!!
a friend said lm 358 creates noise and should be changed!

[kt315]

ahaha! electrostatic field always does influence because WITH THE MOVEMENT THE LOOP.
second your stage is SHIELDING. remember you DO NOT HAVE TO MOVE THE COIL IF
IT IS NOT SHIELDED - !!!!!!!!!!!

[mostafalesnar91]

ahaha! electrostatic field always does influence because WITH THE MOVEMENT THE LOOP.
second your stage is SHIELDING. remember you DO NOT HAVE TO MOVE THE COIL IF
IT IS NOT SHIELDED - !!!!!!!!!!!

my device shield is done correctly!
but the dvice is not stsble when moving,especially in all metal mode!!
i think some ICs need a hammer

[kt315]

pics!!! give pics!!!

[mostafalesnar91]

pics!!! give pics!!!

[mostafalesnar91]

my tgsl test video with 5.5 inch loop!!!!
https://m.youtube.com/watch?v=I0vJhNWY2kE

[SWL]

It was often mentioned here that when nulling the coil, you must adhere to a phase shift of 200 degrees.I guess I don't understand something, but how can there be an angle of 200 degrees between TX and RX? This turns out to be a complete phase reversal .. Isn't that so?Probably it means either +20 or -20 degrees ...

[waltr]

It was often mentioned here that when nulling the coil, you must adhere to a phase shift of 200 degrees.I guess I don't understand something, but how can there be an angle of 200 degrees between TX and PX? This turns out to be a complete phase reversal .. Isn't that so?Probably it means either +20 or -20 degrees ...

Yes, I go for about 20 degree phase shift with RX lagging (later in time) then the TX.
This is the typical phase shift for a DD coil.

I have built coils that nulled with a 200 degree phase shift and they worked fine with proper GB and Disc.

Study the sample periods of the GB & Disc relative to the waveform phase. Then realize that the discrimination circuits (op-amp
filters) are AC coupled and only response to a Change.

This is explained in the book "Inside the Metal Detector".

[SWL]

You did not quite understand me correctly --- there cannot be a phase difference of 200 degrees, maximum 180. Show me an oscillogram with such a phase)))

[waltr]

You did not quite understand me correctly --- there cannot be a phase difference of 200 degrees, maximum 180. Show me an oscillogram with such a phase)))

Mathematically yes, only 0 to 180 degree using Sin functions.
But in a Real Circuit. the Phase can increase through 180 degrees (Inverted) all the way to 360 degree.

DSP operations do 0-360 phase shifts.

Excel spreadsheet plot showing a sine at 0, 20, 180 & 200 degrees phase.

[dbanner]

Factory Tesoro concentric coil ( golden sabre type) was measured to be balanced at around 200 degrees phase difference between TX and RX. That's the concentric.
Now if you were to add 180 to 200 you'd get 20. But what about the synchronized demods, won't they be sampling the negative going RX waveform with such a balanced coil(@200)
But how can this be? Summing two negatives becomes a positive at the end?. Someone can explain.

Now in addition,what if one were to balance a DD coil @200 or conversely, a concentric coil @ 20?
No difference? someone explain.

[dbanner]

Here is Tesoro brown concentric measured at around 20
https://www.geotech1.com/forums/show...own+concentric