TESORO GOLDEN SABRE

[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???

[kt315]

why rx and tx don't have 20 degree phase difference??

do not run for the phase, you must run for right reaction on non-ferrous and ferrous metal moving above coil. a ferrite Carl meant is like 'earth/ground/sole' effect
you simulate on table. take a piece, not big and not small. experiment. you must not get a reaction/sound on the ferrite, being silent.

[Carl-NC]

When you are probing the RX coil signal, where are you probing? Directly on the RX coil, or at the output of the preamp?

Walt is correct, you have a good null at the 5 second mark. It doesn't really matter what the phase is at minimum null because at that point the phase is rolling around quite a bit, anywhere between 0 and 180. Once you have the null minimized, then you apply a ferrite and get the demod clock phases set properly. It's possible that if they are not set right certain targets will have a weak response.