Frequency change TGSL-EDU

[ovidiu]

Hello. I am under construction with a tgsl-edu detector, for which I still have some work to do. I want to ask the experts in the field if in addition to the coil dedicated to this detector, it is possible to make another coil that goes at a higher frequency (for example at 60 khz). I have to do a calibration in the detector circuit, or Is a change in the capacitors in the transmitter enough, or is there a need for another dedicated circuit on this frequency? Any suggestions from you would be welcome. Thank you.

[waltr]

Hello. I am under construction with a tgsl-edu detector, for which I still have some work to do. I want to ask the experts in the field if in addition to the coil dedicated to this detector, it is possible to make another coil that goes at a higher frequency (for example at 60 khz). I have to do a calibration in the detector circuit, or Is a change in the capacitors in the transmitter enough, or is there a need for another dedicated circuit on this frequency? Any suggestions from you would be welcome. Thank you.

I have thought about changing the TGSL Frequency but have not tried .

I have not come up with any reason this would not work. No changes to post sampling stages, integrators, needed.

You may need to adjust the sampling timing to get proper ground balance and discrimination.
And of course the TX and RX resonant caps (or coil inductance) to set frequency and then obtain the correct RX Phase.

One other thought, 60kHz may cause timing to be more critical due to much shorted period. May be that the TX oscillator will not work well but you'll need to try to find out. Maybe first try 20-30kHz then later increase to 50-60kHz.

I was thinking of reducing the frequency to have better response to high conductors like silver coins. Maybe to 5-7kHz.

Please do post in this thread results of your experimentation.

[ovidiu]

Thanks for the information you gave me. However, I try in several ways to reach a higher frequency. As it is known, a higher frequency is good at detecting small gold flakes, but at the expense of depth. I'm experimenting and I'll keep you posted.

[waltr]

Yes, knew you wanted to try detecting small natural gold.
60kHz should do it.

[dante_e25]

I have a Minelab Eureka Gold that switches between 6.4kHz, 20kHz, & 60kHz. There are 3 older models that switch frequencies too, if you can pick up one of those it would give you an idea on how solve your problems. 60kHz is good for small shallow gold, but you need a small (6”) sensitive coil and to keep your expectations to shallow 2” depth on mineralized ground and maybe 4” on regular ground with no emf.

[kt315]

I have a Minelab Eureka Gold that switches between 6.4kHz, 20kHz, & 60kHz. There are 3 older models that switch frequencies too, if you can pick up one of those it would give you an idea on how solve your problems. 60kHz is good for small shallow gold, but you need a small (6”) sensitive coil and to keep your expectations to shallow 2” depth on mineralized ground and maybe 4” on regular ground with no emf.

can you share pics of the board? is it controller based or whole analogue? TIA