help problem TGSL

[ashefr10]

HELLO, I have a small problem for tgsl my settings, I do not know if the phase difference is measured between TX and RX or TX between output and U101. thank you to inform me. And est'il possible to obtain 4 mV output of U101 I have just over 100 mV to a minimum. Thank you to those who can help me

[ashefr10]

I would also like to know if I should adjust the nulling before the GEB or the reverse.
must set the GEB in any metal or discrimination. are what I have to use a multi-turn potentiometer for the GEB?