VLF null and frequency

[manhunt47]

I was curious to check the frequency response of the Nautilus circuit
But since the coil inductance is unknown, but the transmitter's only frequency is specific, and it was also said that the receiver's resonant frequency is the same as the transmitter, so I first calculated the amount of INDUCTANCE coil RX and then simulated it.
Of course I did not know the type of transistor.

[manhunt47]

Continuing along the above logic, since balancing coil Everytime detector is turned on, and due to complexity involved in setting up detector before hunting, and wanting to make things simpler and easier to use, the closer resonance coil design was abandoned in favour of a wider spread, so balancing coil within a marginal null would be sufficient for the purposes of mass production and overall simplicity of operation of detector for customer.
There are more elegant ways of saying this, but you get the meaning.
This is my speculative thoughts and could be entirely bull crap

In general, I agree with the fact that companies, with a large difference between the two TX and RX frequencies, make it easier to produce metal detectors and less sensitivity.

[manhunt47]

I too couldn't find accurate technical information on Nautilus coil Rx resonant frequency, until I read the Nautilus patent author Jerry Tyndall.
You see therein contain details/data on coil, enough to ascertain what Jerry was up to. Then I realized that the Nautilus DMC 2b coil was most likely bifilar design with tx an Rx freq, closer together(somewhere around 14khz). The circuit architecture was very much the standard for motion VLF, so why was the DMC2b winning competition events, and got tremendous success and reputation for deepseeker?
Four elements, firstly, transistor preamp in coil housing.
Secondly, balanced coils in full resonance.(bifilar centre tap TX design with dual buck coils)
Thirdly, a third all metal channel running side by side with motion discrimination, with it own separate audio.
Fourthly, adjustable tx power.
The only differences I could find from say the tgs circuit( besides unique side by side all metal channel) were in the phase shifting, and the coupling to the switches(gates)4066.( Normally with series resistor and cap to ground, in the DMC2B it was capacitor in series and resistor to ground)yet another clue for stability.
Everything else was like silver sabre plus, which ain't a deepseeker by any means!!
Of course the final big difference was the coils being in closer phase, requiring R and C balance pots to fine tune the null before hunting. This I believe is what closer resonance spread does, it requires very fine balancing to achieve stability.

Hello dbanner
I did not work with this device Nautilus at all, and it's hard to ask about it, but for me, its loop and circuit structure is very strange.
Another interesting topic was that you said the TX and RX frequencies are the same.
And I think this is exactly what you said****(((( This I believe is what closer resonance spread does, it requires very fine balancing to achieve stability))))****

[dbanner]

Continuing along the above logic, since balancing coil Everytime detector is turned on, and due to complexity involved in setting up detector before hunting, and wanting to make things simpler and easier to use, the closer resonance coil design was abandoned in favour of a wider spread, so balancing coil within a marginal null would be sufficient for the purposes of mass production and overall simplicity of operation of detector for customer.
There are more elegant ways of saying this, but you get the meaning.
This is my speculative thoughts and could be entirely bull crap

[dbanner]

I too couldn't find accurate technical information on Nautilus coil Rx resonant frequency, until I read the Nautilus patent author Jerry Tyndall.
You see therein contain details/data on coil, enough to ascertain what Jerry was up to. Then I realized that the Nautilus DMC 2b coil was most likely bifilar design with tx an Rx freq, closer together(somewhere around 14khz). The circuit architecture was very much the standard for motion VLF, so why was the DMC2b winning competition events, and got tremendous success and reputation for deepseeker?
Four elements, firstly, transistor preamp in coil housing.
Secondly, balanced coils in full resonance.(bifilar centre tap TX design with dual buck coils)
Thirdly, a third all metal channel running side by side with motion discrimination, with it own separate audio.
Fourthly, adjustable tx power.
The only differences I could find from say the tgs circuit( besides unique side by side all metal channel) were in the phase shifting, and the coupling to the switches(gates)4066.( Normally with series resistor and cap to ground, in the DMC2B it was capacitor in series and resistor to ground)yet another clue for stability.
Everything else was like silver sabre plus, which ain't a deepseeker by any means!!
Of course the final big difference was the coils being in closer phase, requiring R and C balance pots to fine tune the null before hunting. This I believe is what closer resonance spread does, it requires very fine balancing to achieve stability.

[pustareka]

http://kamrad-club.ru/-razdel-master...aquasound.html https://www.geotech1.com/forums/show...446#post254446

[kt315]

you have a generator (sorry i do not remember a call of this type of generator, we call ТРЕХТОЧКА) with
known frequency and known capacitor value. take a formula of classic resonance and calculate.

[manhunt47]

https://dfiles.ru/files/au0qyjdqg?redirect

I have read all the data you sent from the Nautilus device, but I did not get any information about the values of the RX and TX Coil inductances.

[manhunt47]

https://dfiles.ru/files/au0qyjdqg?redirect

Thanks kt315

[kt315]

https://dfiles.ru/files/au0qyjdqg?redirect

[manhunt47]

RX part of Nautilus coil has pre-amplifier on transistors. this small trick gives all advantages.

Do you have a snapshot of this design?
To simulate it

[manhunt47]

RX part of Nautilus coil has pre-amplifier on transistors. this small trick gives all advantages.

Do you have a snapshot of this design?
To simulate it

[kt315]

RX part of Nautilus coil has pre-amplifier on transistors. this small trick gives all advantages.

[manhunt47]

Clue: Nautilus circuit is known for incredible depth, while maintaining stability. Not a coincidence that tx and Rx are close together. This jives with your observations. Conclusion, take Nautilus phase shifters, apply to tgsl, now balance tx and Rx at closer resonant frequency, realize greater depth of detection.

Hello dbanner
Can you give me more detailed information about this device Nautilus?
For example, TX and RX frequencies as well as loop inductances
Because I could not understand the behavior of this device

Because you are here to point out that the TX and Rx frequencies are very close and the device has a good depth and is stable.

[manhunt47]

Nothing has been removed.
I suspect you have copy and pasted photos that exist only on your computer, and therefore they're not visible to anyone on the forum.
To correctly attach files to your post:
1. Select "Go Advanced".
2. Select "Manage Attachments".
3. Then select "Add Files", browse, and upload.

thank you Qiaozhi