Wanted "ADMIRAL"

[Toros]

What is the actual size of board?

~ 84x87 cm.

[Sarkim]

I use 68 ohm but can be use trimpot for fine tuning of oscillator current

What is the actual size of board?

[plcamjad]

Thank you. I will assemble the painting within the next week. Thank you from the State of Jordan

[bonchev2]

I use 68 ohm but can be use trimpot for fine tuning of oscillator current

[plcamjad]

What is the value of resistance, with all due respect and appreciation?

[CEBRAIL]

Hi Cebrail,
What do you mean by adjusting the resonance?
The transmitter is autogenerator - switching the power it started generate sine wave, and if the value of the capacitor changes, it only affects the frequency.
The receiver is an amplifier implemented according to a common base circuit and is a non-resonant circuit. Is it a matter of selecting the capacitor, that is in parallel of the 15k in the emitter of the transistor?
Greetings.

tx 23 vpp bc337 connected 33 k bc 327 connected resistor ohm ground opamp LM 393 2 pin 1pin 7 pin and rx serial parallel capacitor tl072 connected resistors

[getsa]

My coils are not affected by graphite coated soil. If the resonance is adjusted well, it goes deep very well. I removed the copper belt lock from a depth of 50 cm. The size is about 3cm

Hi Cebrail,
What do you mean by adjusting the resonance?
The transmitter is autogenerator - switching the power it started generate sine wave, and if the value of the capacitor changes, it only affects the frequency.
The receiver is an amplifier implemented according to a common base circuit and is a non-resonant circuit. Is it a matter of selecting the capacitor, that is in parallel of the 15k in the emitter of the transistor?
Greetings.

[bonchev2]

My coils are not affected by graphite coated soil. If the resonance is adjusted well, it goes deep very well. I removed the copper belt lock from a depth of 50 cm. The size is about 3cm

Make video I like to see it. Thanks

[CEBRAIL]

My coils are not affected by graphite coated soil. If the resonance is adjusted well, it goes deep very well. I removed the copper belt lock from a depth of 50 cm. The size is about 3cm

[bonchev2]

This is Admiral1 VLF Metal Detector.
Coil is TX 0,4mm 1mH 330nf, RX 0,25mm 12mH 22nf
Calculated Frequency of 8,7kHz. Null voltage 9mV possible lower with more sens

RX 22nf ? Strange, what must be frequency of receiver?

[Toros]

Hi
TX 1.114 Mh-0.30 330NF
RX 7.15 Mh- 0.60 68NF

This is Admiral1 VLF Metal Detector.
Coil is TX 0,4mm 1mH 330nf, RX 0,25mm 12mH 22nf
Calculated Frequency of 8,7kHz. Null voltage 9mV possible lower with more sens

[pito]

I tested both, not much different, I suspect that bad shield is causing more ground influence, so I make coil inside copper tubing = 100% shield.
testing results = The influence of the soil is the same for all 3 of them.

coil inside copper tubing.


to check quality of shielding spray some water on finished coil, no signal changes = good shielding

[CEBRAIL]

Which one is better guys, aluminum foil shielded coils or graphite?

I use graphite

[bonchev2]

Which one is better guys, aluminum foil shielded coils or graphite?

[bonchev2]

Thanks gurdal