AV multiband VLF receiver

[mustefa ubram]

Excellent wm6 for schematic
wm6 and j-p
I have no experience with this frequency range.and i have question
How to measure the resonance frequency of the use of metals in the circuit when the transmitter?
Whether the transmitter of the loop antenna to generate frequency vlf is right?
Vlf range of frequencies to transmit and detect what is right??(3kh-4kh-5kh.....30kh)
Transmitter frequency to the ground after hitting the metal out of the ground in what form?
The receiver can reveal how the radial wave vlf?

[J_Player]

Excellent wm6 for schematic
wm6 and j-p
I have no experience with this frequency range.and i have question
How to measure the resonance frequency of the use of metals in the circuit when the transmitter?
Whether the transmitter of the loop antenna to generate frequency vlf is right?
Vlf range of frequencies to transmit and detect what is right??(3kh-4kh-5kh.....30kh)
Transmitter frequency to the ground after hitting the metal out of the ground in what form?
The receiver can reveal how the radial wave vlf?

I do not believe any frequency that you transmit will allow you to detect buried metal with this receiver.
But I may be wrong.
Other experimenters use any frequency between 70 KHz to 150 KHz

Best wishes,
J_P

[okantex]

J_Player ,

do you think that emfad is narrow band reciver, yes it has a tunner , but it's range is too much.when this circuits bands are considered to emfad it is enough narrow
look , with wide band ,you wont able to recieve more frequencies at each listening.you will generally have one frequency ,but when you have more frequency at same time , you will always tune your led to powerfull station's upper noise level as PDK does fro VHF waves. it will be good to add multiturn pot as threshold adjustment.

what do you think of it.
but still this receiver has less tr than emfad.

[J_Player]

J_Player ,

do you think that emfad is narrow band reciver, yes it has a tunner , but it's range is too much.when this circuits bands are considered to emfad it is enough narrow
look , with wide band ,you wont able to recieve more frequencies at each listening.you will generally have one frequency ,but when you have more frequency at same time , you will always tune your led to powerfull station's upper noise level as PDK does fro VHF waves. it will be good to add multiturn pot as threshold adjustment.

what do you think of it.
but still this receiver has less tr than emfad.

I think this circuit is a good toy to experiment with to learn the directional properties of ferrite antennas.
I do not think it is a narrow band tuner.
I think if you want a narrow band tuner, then you should select the narrow band that you want to investigate, and then build a new design narrow band tuner to listen for your frequency.

Best wishes,
J_P

[FrancoItaly]

Hi All

As Esteban said also a passive receiver may be a sensitive lrl, then there is no need for trasmitting any wave, it's the signal that comes from buried target that goes away. A stimulus or trasmitter signal can serve only for a reference signal, as the signal from buried target it has not a precise frequency, somehow it works on different forms of signals, magnetic, electromagnetic, infrared.

Best Regards

[Qiaozhi]

Hi All

As Esteban said also a passive receiver may be a sensitive lrl, then there is no need for trasmitting any wave, it's the signal that comes from buried target that goes away. A stimulus or trasmitter signal can serve only for a reference signal, as the signal from buried target it has not a precise frequency, somehow it works on different forms of signals, magnetic, electromagnetic, infrared.

Best Regards

Has anyone tried to build the TOTeM pistol detector from "Inside the METAL DETECTOR"?

It is intended as an experimental platform for investigating LRL technology, and has both passive and active modes; plus audible (beeper) and visual (LED & meter) outputs. The beeper can also be turned off for clandestine detecting.

There is no PCB for this design, as it was built on stripboard. However, anyone is welcome to design one and post it here.

[FrancoItaly]

Hi All

I don't know the TOTeM pistol detector but in my experience only a passive receiver with the TX stage off,it doesn't have enough sensitivity, it must amplify some unknow signal of unknow frequency. My most recent lrl uses a high gain rf stage in self oscillating condition: it's a passive receiver, it doesn't trasmit any signal but it's very sensitive to external influence. The TX signal dramatically reduces the signal from buried target but the lrl it remain sensitive to Sky/compass effect.



Best Regards

[mustefa ubram]

I do not believe any frequency that you transmit will allow you to detect buried metal with this receiver.
But I may be wrong.
Other experimenters use any frequency between 70 KHz to 150 KHz

Best wishes,
J_P

Which part of the circuit can absorb from the environment, much frequency tables?
Specifically?
Please show on the schematic

[J_Player]

Which part of the circuit can absorb from the environment, much frequency tables?
Specifically?
Please show on the schematic

Hi mustefa ubram,
The only parts of the circuit that can absorb RF from the environment are shown below.
But also, other components can absorb from the environment in very small amounts.

Best wishes,
J_P

[mustefa ubram]

hi
I've read on this system.I believe that these systems requires a filter.To match with the transmitter.Because there are a lot of disturbing signals in the signal and is absorbed by the ferrite The system reacts to these signals interfere.And can be difficult to detect transmitter signals.
I believe there is a filter that allows the recipient to respond only to our own frequencies.
In the general case requires the system to a point that is specified in the Filter..
What do you think?

[mustefa ubram]

hi
I've read on this system.I believe that these systems requires a filter.To match with the transmitter.Because there are a lot of disturbing signals in the signal and is absorbed by the ferrite The system reacts to these signals interfere.And can be difficult to detect transmitter signals.
I believe there is a filter that allows the recipient to respond only to our own frequencies.
In the general case requires the system to a point that is specified in the Filter..
What do you think?

Anyone disagree?

[WM6]

Anyone disagree?

Which filter do you mean?

This is multi-band receiver with selective tuned band, which is some sort of filtering.

You do not need filter here, or you need multi-filter (not worth all efforts). But you need good sine transmitter.

[J_Player]

Which filter do you mean?

This is multi-band receiver with selective tuned band, which is some sort of filtering.

You do not need filter here, or you need multi-filter (not worth all efforts). But you need good sine transmitter.

It appears that the readers of this circuit do not understand it is simply a toy to experiment with and learn the directional properties of ferrite antennas.
But they want a narrow band tuner. Why? Who knows?

I think if they want a narrow band tuner, then they should select the narrow band that they want to investigate, and then build a new design narrow band tuner to listen for the frequency they want to hear. This circuit is a waste of time to modify to become a narrow band receiver.

Maybe we need a new circuit that uses a crystal clock with digital divider and PLL to select desired frequency, then a narrow band adjustable notch filter to find the exact frequency that the receiver will tune to. Then we should also have a bank of capacitors and matched ferrites for each band, which can be adjusted 20-30% within the band by the digital logic and notch filters in combination with adjustable capacitors.
Maybe 20 frequency bands would be good to start with.
Then we can add more ferrite-capacitor antennas to get more frequency bands when we find that none of the 20 initial bands find treasure.

What do you think?
Are we ready for a new circuit design?


Best Wishes,
J_P

[mustefa ubram]

Which filter do you mean?

This is multi-band receiver with selective tuned band, which is some sort of filtering.

You do not need filter here, or you need multi-filter (not worth all efforts). But you need good sine transmitter.

If you select any of the bands is not heard no noise except for the frequency of the playoffs?
Filtering to eliminate noises that disturb land.

[mustefa ubram]

It appears that the readers of this circuit do not understand it is simply a toy to experiment with and learn the directional properties of ferrite antennas.
But they want a narrow band tuner. Why? Who knows?

I think if they want a narrow band tuner, then they should select the narrow band that they want to investigate, and then build a new design narrow band tuner to listen for the frequency they want to hear. This circuit is a waste of time to modify to become a narrow band receiver.

Maybe we need a new circuit that uses a crystal clock with digital divider and PLL to select desired frequency, then a narrow band adjustable notch filter to find the exact frequency that the receiver will tune to. Then we should also have a bank of capacitors and matched ferrites for each band, which can be adjusted 20-30% within the band by the digital logic and notch filters in combination with adjustable capacitors.
Maybe 20 frequency bands would be good to start with.
Then we can add more ferrite-capacitor antennas to get more frequency bands when we find that none of the 20 initial bands find treasure.

What do you think?
Are we ready for a new circuit design?


Best Wishes,
J_P

Not need more bands Treasure Hunt.
We need a powerful transmitter and a wrist receiver that the transmitter.For example, if the transmitter sends a frequency 5 kHz The receiver will only receive 5 kHz frequency And not heard another noise.
A Question:
Can reveal whether the recipient New metal in the soil?