Wanted "ADMIRAL"

[Zinou]

Hi, I have the same problem with big object no detection after 45cm. Can you help me ?

[Carl-NC]

The TX frequency has nothing to do with the RX coil or the RX capacitor.

[Zinou]

Hi, I found the same frequency of the coil (Tx: 8.5khz ) on Rx, I changed the value of the capacitor Rx but it's still not changing(8.5khz),
Is this good ? (Sorry for my English)

[Carl-NC]

38 ohms should not be a problem. The RX coil should not affect the TX frequency or amplitude.

[bonchev2]

Thanks for the answers. I ask because I'm making a new one. bigger coil
DD 33 cm for the Admiral and I want to get it right. Today I wound the windings Tx 1mH R-2.8 ohms, 0.47mm & Rx 11.2mH R-38 ohms 0.23mm.I'm worried that the resistance of the Rx is 38 ohms.
At first look the device works properly, the frequency changed from 8.4kH to 8kH and the volts of the Tx went from 18v to 20v.

Do you think i need to reduce the windings of the Rx to lower the resistance and the induction respectively or leave it like that? Rx-132 windings.

[Carl-NC]

Admiral should be very tolerant of different RX coils. Smaller inductance means fewer turns which will reduce target sensitivity but it also reduces ground & EMI signals so SNR doesn't change much. You can restore sensitivity by increasing the preamp gain.

[bonchev2]

Capacitor on TX ? I don put parallel capacitor on RX and is work fine

[Op04]

You need to change capacitor then

[bonchev2]

Hello colleagues! I want to ask if I do Rx 7.6mH (instead 12mH)will I lose depth?

[bonchev2]

[bonchev2]

The device works well for coins but does not detect large non-ferrous metals. When I passed with the big object, a strong signal is indicated on tl072 pin 7 but there is no sound indication at all. Has anyone had a similar problem and if so can it be fixed?

[CEBRAIL]

Tx 1 mh 3 ohm 330 nf.. rx 12 mh 30 ohm 33 nf

[CEBRAIL]

https://youtu.be/I62-fFSzU8we

[getsa]

Your current depth result is OK.

[bonchev2]

thanks for your help getsa Can you tell me what is the normal depth of the device? For example a 1 euro coin.To know the capabilities of the device. now catches them at 25-28 cm. Thanks again