Adding tones to Raptor

[h9361]

I don't have a PCB design, maybe there is one on the forum.

Hello Dear Carl
I tested Bandido II and TGSL.
I have a question, do you have any suggestion (changing in pcb values) for increasing its sensitivity?

[Carl-NC]

All I can suggest is to experiment with gains and filters. But I don't have anything specific.

[h9361]

All I can suggest is to experiment with gains and filters. But I don't have anything specific.

Thanks you.
For starting, Can you tell me which gains and filters?

[Carl-NC]

Preamp gain, sample-hold gains, differentiator gains; it's all a balance between achieving sensitivity and avoiding overload, especially in bad ground. There is no magic change you can make to improve sensitivity, Tesoro would have done that already.

[h9361]

That will work but I think it will only add a fake threshold level and will not help with sensitivity. TGSL is designed for silent-search disc-only, there is no all-metal channel to drive the audio which is what you need for adding an effective threshold. The Bandido II circuit is a good example. If you have ITMD3, then the VLF-Disc design also shows how to do this, and it also shows a way to do 2-tone audio.

Hello
Dear Carl i have a request.
Can you tell me application of Auto switch and Retune option in the schematic?
How should i use the Auto and Retune?
Thanks.

[h9361]

Preamp gain, sample-hold gains, differentiator gains; it's all a balance between achieving sensitivity and avoiding overload, especially in bad ground. There is no magic change you can make to improve sensitivity, Tesoro would have done that already.

I compared schematic of two Tesoro golden sabre light and Tesoro bandido 2 umax.
If i understand correctly, the Sabre-light has different value SAT than Bandid.
So, i think the Bandid has more stability, is that correct?!

[Carl-NC]

The Sabre does not have a zero-motion all-metal channel so there is no SAT at all. It is a silent-search detector. The Bandido is a more advanced design and can be used in threshold mode.

On the Bandido, the AllMet mode allows locking the SAT circuit so it is not continuous; in the is mode, you would pull the switch (momentarily) to Retune to update the SAT. The Auto switch bypasses this function and forces the SAT to run continuously, as if you were constantly pulling the Retune switch.