TESORO GOLDEN SABRE

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Set the gb trim in mid position.
Null coil with rx lead tx by 20 degrees.
Then adjust the gb trim so that ferrite is just barely rejected.

Without oscilloscope I have observed that using good wideband AC milli voltmeter(or any ac milli voltmeter for that matter regardless of bandwidth limitations, because we are not concerned with absolute values, but with minimum value) null for minimum output of preamp and gb trim adjust to edge of reject ferrite( checking also for good detection range in so doing), everything seems to work and fall into place. A little back and forth is necessary to optimize detection distance.
If the gb trim cannot reject ferrite within its adjustable range then you will know that your null is far away from the 20 degrees.

This 20 degrees is measured on oscilloscope from factory tesoro search head connected to original tesoro metal detector.

[mostafalesnar91]

I completed this project without using oscilloscope!!
just with a simple multimeter!!
very very easy!!!!!!!!!!https://m.youtube.com/watch?v=eEQmZNyUJo4

So I already went the right way with the multimeter

[mostafalesnar91]

See the photo in the best condition for the coil!!!! This coin your country should sense in a few centimeters????[ATTACH]58119[/ATTACH]
[ATTACH]58120[/ATTACH]

this coin

[mostafalesnar91]

A scope is useful for many other things. Without one it's like trying to work with one hand tied behind your back.

I will test this method of removing the ferrite today. When I do this, the coin should be sensed above 30 cm. If it doesn't, it means that all this time has been wasted, because on the first day when I joined this site, you said that it should be for The nulling must be scoped so that you can adjust the phase difference, but now I see that all my coils are automatically adjusted to 20 degrees and there was no need for a scope.

[Qiaozhi]

For Tesoro designs the RX signal will be offset by approximately 20 degrees.

meant 20 degrees measured before op amp or after? preamp gives itself some phase shift?

Output of the preamp. See pages 140 and 141 of ITMD.

[kt315]

For Tesoro designs the RX signal will be offset by approximately 20 degrees.

meant 20 degrees measured before op amp or after? preamp gives itself some phase shift?

[Qiaozhi]

If the coil nulling by removing the ferrite, what is the need for a scope? What is the use of a scope?

A scope is useful for many other things. Without one it's like trying to work with one hand tied behind your back.

[mostafalesnar91]

Setting the RX null to the lowest possible amplitude is not the correct way to balance the coil.
Turn the DISC pot to minimum and the GB pot to the middle, and then adjust the null until ferrite is rejected.
For Tesoro designs the RX signal will be offset by approximately 20 degrees.
If you don't understand what you're doing, then I suggest reading ITMD -> Inside the METAL DETECTOR - Second Edition - Published 2015

If the coil nulling by removing the ferrite, what is the need for a scope? What is the use of a scope?

[Qiaozhi]

Now I have to set the rx to the lowest possible amplitude where the waveform changes I did this but the sense of metals was poor
Why does the shift not happen? Why is the tx waveform static when nulling and not moving left or right?

Setting the RX null to the lowest possible amplitude is not the correct way to balance the coil.
Turn the DISC pot to minimum and the GB pot to the middle, and then adjust the null until ferrite is rejected.
For Tesoro designs the RX signal will be offset by approximately 20 degrees.
If you don't understand what you're doing, then I suggest reading ITMD -> Inside the METAL DETECTOR - Second Edition - Published 2015

[mostafalesnar91]

Now I have a phase difference of 20 degrees, but in pre-phase!!
But it must be post-phase, right??

ok. where you see '20 degrees' phase shift recommended? let to see the text.

See the photo in the best condition for the coil!!!! This coin your country should sense in a few centimeters????

[mostafalesnar91]

The RX frequency will always be the same as the TX frequency regardless of how you tune the RX coil.
Let's say the TX frequency is 14kHz, and you tune the RX coil to 16kHz. The RX frequency will still be 14kHz. All you have done is tune the RX coil off resonance.
The more you tune the RX coil away from resonance, the lower the amplitude. The frequency stays the same.

Now I have to set the rx to the lowest possible amplitude where the waveform changes I did this but the sense of metals was poor
Why does the shift not happen? Why is the tx waveform static when nulling and not moving left or right?

[kt315]

Now I have a phase difference of 20 degrees, but in pre-phase!!
But it must be post-phase, right??

ok. where you see '20 degrees' phase shift recommended? let to see the text.

[Qiaozhi]

please help me

The RX frequency will always be the same as the TX frequency regardless of how you tune the RX coil.
Let's say the TX frequency is 14kHz, and you tune the RX coil to 16kHz. The RX frequency will still be 14kHz. All you have done is tune the RX coil off resonance.
The more you tune the RX coil away from resonance, the lower the amplitude. The frequency stays the same.

[mostafalesnar91]

thank you guys!!
tx only 14.47
rx only 13.86
Connect tx and rx together to circuit 14.47 tx and 14.37 rx
Why rx does not reach frequency 16????
Now I have a phase difference of 20 degrees, but in pre-phase!!
But it must be post-phase, right??
how to make rx frequency to 16???[ATTACH]58113[/ATTACH]

please help me

[mostafalesnar91]

thank you guys!!
tx only 14.46
rx only 13.86
Connect tx and rx together to circuit 14.30 and 14.20
Why rx does not reach frequency 16????
Now I have a phase difference of 20 degrees, but in pre-phase!!
But it must be post-phase, right??
how to make rx frequency to 16???