VLF null and frequency

[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

[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))))****

[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 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.

[Koala]

coil doesn't settle down for the first hour detecting ?

https://www.youtube.com/watch?v=oMwSMDK9__U&t=0s&list=PLpEdWf-sVlbgBKmT6uS0Avdi2t9b-tWhG&index=2


like the idea of stereo audio

[manhunt47]

Hello
Someone can help me
Previously, I could write the font and color of the book and even put the sticker, but now that toolbar does not exist.

[dbanner]

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.

[ATTACH]45567[/ATTACH][ATTACH]45568[/ATTACH]

Your tests confirm my logical observations, though I never pursued it. It is precisely what I would have expected.

[dbanner]

The tx coil inductance I'd a known commodity. 14khz @ x capacitance, I can't remember, but I did check it.
Now check out the Nexus. I t had balanced TX and Rx at unity resonance.
Cheers, I be back, after I drink some more coffee.

[manhunt47]

The tx coil inductance I'd a known commodity. 14khz @ x capacitance, I can't remember, but I did check it.
Now check out the Nexus. I t had balanced TX and Rx at unity resonance.
Cheers, I be back, after I drink some more coffee.

I did not find any schematic information about nexus devices.
I even saw several forums.

[pustareka]

NAUTILUS ТХ и CХ имеют по 4.2 Ом, толщина провода 0.45мм - одна пара хвостов соеденена вместе и кинута на землю, вторая пара на платку в параллель им пленочный кандер неизвестного номинала. РХ имеет сопротивление 26 Ом толщина 0.3 мм, в параллель РХ стоит кандер 22Н. Корпус катушки изнутри промазан графитом и обе половинки корпуса. TX= 4.2 R WIRE 0.45mm CX=4.2 R WIRE 0.45mm RX = 26 R WIRE 0.3mm C_RX=22n Transistori 2N5088 GRAFIT SHILD CASTOTA NAUTILUS F 13965 Hz FAZA TX/RX = 0 GR.

[Qiaozhi]

NAUTILUS ТХ и CХ имеют по 4.2 Ом, толщина провода 0.45мм - одна пара хвостов соеденена вместе и кинута на землю, вторая пара на платку в параллель им пленочный кандер неизвестного номинала. РХ имеет сопротивление 26 Ом толщина 0.3 мм, в параллель РХ стоит кандер 22Н. Корпус катушки изнутри промазан графитом и обе половинки корпуса. TX= 4.2 R WIRE 0.45mm CX=4.2 R WIRE 0.45mm RX = 26 R WIRE 0.3mm C_RX=22n Transistori 2N5088 GRAFIT SHILD CASTOTA NAUTILUS F 13965 Hz FAZA TX/RX = 0 GR.

Please read the forum rules -> Basic Rules of the Forums
and make your posts in English.

[pustareka]

[manhunt47]

I do not understand the language of your writing, especially on the image

[manhunt47]

Please read the forum rules -> Basic Rules of the Forums
and make your posts in English.

Hello Qiaozhi
Admin if possible help me
Previously, I could write the font and color of the book and even put the sticker, but now that toolbar does not exist
My toolbox does not exist to change fonts and more

[Qiaozhi]

Hello Qiaozhi
Admin if possible help me
Previously, I could write the font and color of the book and even put the sticker, but now that toolbar does not exist
My toolbox does not exist to change fonts and more

What is the exact problem?
If you're asking about changing the font or the size and color then there should be a toolbar that allows you to do this.
If the toolbar is not there, then it must be a problem with your browser.