PD Discussions

[aft_72005]

Hi All
The better system to eliminate slow drift in DC signals it's to use a motion circuit, I use a comparator, the signal goes to one input by a capacitor and the same input is polarized at half DC power and the other input goes to a potenziometer for sensibility regulation: If you use a CA3130 or CA3140 the capacitor may be about 1 microfarad.

Best regards

Hi FrancoItaly
Yes, this add on circuit the way for stability at high sensitivity
Best regards.

[Qiaozhi]

I have moved all the PD discussions to this new thread, as the original thread was about the Zahori device.

[J_Player]

Hi J_Player
Thanking for your attention and thanking for your help , your are fine engineer , you pointed to points which also I thinking about it !!!!!!
I must be use reference zener diode( instead ordinary zener diode) , other instability was Darlington transistors at output ( see PD circuit-not original heatkit circuit) .
My built and modified MD vas very stable on workbench !!!!!!!!!!!! . it can detect 17 inch computer monitor from 1.5 meter easy in workstation . !!!! but problem will begin
When begin moving PD in search aria!!!!!! ., may be must be
Not tuned for very fine null ( null tuned very fine) but when a little out of fine null . sensitivity is fall down and didn’t act as LRL
maybe this is sky ground effect but Coil far from ground !!!!! . crux is here, be stable
in high sensitivity .
I remember Qiaozhi ideas , super fine , super sensitive detector but point here with stability .
Best regards.

Hi Aft,
When you convert a GD348 to PD, you make a change to move the omega coil close to the circuit board and the ferrite. This will cause the omega to see the ferrite and the metal from the circuits as a treasure target. You null the omega RX coil so it will ignore this metal target signal. This is the same condition that wee see on an ordinary VLF detector that has the small amount of metal in the cable that connects to the detector coil, or sometimes a small metal screw to connect the coil. The effect of the small amount of metal in the cable and shield is to reduce the sensitivity of the detector coil. We see this happens on an ordinary detector because the cable for the coil signal is detected as a copper treasure at some small amount. This detection of cable wire is nulled out from an ordinary VLF detector, and also takes away some small amount of sensitivity.

But in the case of the PD, the amount of metal that is nulled out is much more because it includes several circuit boards and metal parts like coils and the ferrite. This is no longer a small amount of metal that has little effect for the detector. And you still find 1.5m detection of a large screen because it is a very sensitive detector. But you see the problem when you take the detector to the field.

Now you no longer have a large monitor to detect. You are looking for tiny signals from the ground. so you turn up the sensitivity and you begin to find a lot of tiny signals from the sky, the ground, from RFI, and other tiny noise. Your signal to noise ratio is poor because you have the metal parts of the boards and ferrite near the search coil. So you expect the small signals to be lost in noise.

But we hear there is magic in this PD. We hear it is necessary to keep the ferrite near the search coil because this is how we will find the treasure signal. We hear how it works for finding gold an more than 30 meters on a lucky day, and we see a video that shows it making beeps from 2 meters. So is there some truth to the idea of putting the ferrite near the omega search coil and nulling it?

Maybe, but I have seen nobody demonstrating any certain success with a PD clone built. I see a video of only the Alonso PD beeping from 2 meters. Why not all the clones?

I already explained about the sensitive part of the omega circuit, and I explained that most clone builders are not careful to keep the circuit boards away from the search coils similar to what you see in the Alonso PD. But there is more:

Not many people listened to Morgan to understand the PD cannot be calibrated at the workbench. This is done outside away from power and other electric noise. And it takes a long time. The trick is to null the ferrite to the omega coil. Some people have special methods for doing this. You remember the Alonso PD has a gap between two ferrite rods, which is different than a single ferrite rod. Adjusting this gap can make some fine tuning adjustments. But the position of the ferrite assembly has a much larger impact on the tuning of the circuit. I suggest you contact other PD builders to learn what they know about successful ways to null the ferrite.

Also, the ferrite material makes a difference. You want a ferrite designed for VLF in the 100 khz range. A ferrite designed for AM broadcast should work fine. But you may be better with a special ferrite that was designed to pick up a clock signal that is broadcast at 60 KHz. These are found in Sony automatic adjusting clocks sold to the American market. If you are using an unknown ferrite, it could be a ferrite that is optimized for the megahertz range and works poorly at Khz, or even attenuates the coil current.

Suppose you get the ferrite nulled so it picks up some kind of metal signal in the field. You still have the sky effect and the wall effect. There is no mystery about these. We know that VLF is absorbed by the ground in an amount that will depend on the conductivity of the ground. More moisture will cause more of the RF to be absorbed. If you hold the coil horizontally, you can expect part of the RF travelling to the ground will be absorbed and part will be absorbed into you because you are standing directly behind the coils and you are conductive for VLF. But as you turn the coil down, you are directing it where more will be absorbed into the ground. Then you turn it up where less of the VLF is absorbed to the ground because it is sent to the sky. We expect the Rx signal to change because the RF load on the TX is changing. And there is also a question of what part of the RF is reflected or refracted in a way that it returns and is picked up by the Rx. If this is happening when the coil is in a horizontal position or pointing down, then pointing it up will not allow the same near-field reflections/refractions to reach the Rx. In any of these directions, your body is usually at the back side of the coils acting as a grounded shield, so the back of the coil cannot make a mirror image of what is seen at the front.

Then we come to the final puzzle: What is the treasure signal?
According to reports, the best of the PDs are nulled in a manner that the sky effect has little impact on the operation, and the locator responds only to gold or silver, with minor amounts of response to aluminum or brass. Apparently these PDs are tuned in a way that has discrimination, and may not be working on a VLF absorption/reflection principle at all. If they are not, then what?

I suppose it does not matter if all you can find is noise in the air at the moment.


Best wishes,
J_P

[aft_72005]

I have moved all the PD discussions to this new thread, as the original thread was about the Zahori device.

Hi Qiaozhi
Thanks for trouble .
Best regards.

[aft_72005]

Hi Aft,
When you convert a GD348 to PD, you make a change to move the omega coil close to the circuit board and the ferrite. This will cause the omega to see the ferrite and the metal from the circuits as a treasure target. You null the omega RX coil so it will ignore this metal target signal. This is the same condition that wee see on an ordinary VLF detector that has the small amount of metal in the cable that connects to the detector coil, or sometimes a small metal screw to connect the coil. The effect of the small amount of metal in the cable and shield is to reduce the sensitivity of the detector coil. We see this happens on an ordinary detector because the cable for the coil signal is detected as a copper treasure at some small amount. This detection of cable wire is nulled out from an ordinary VLF detector, and also takes away some small amount of sensitivity.

But in the case of the PD, the amount of metal that is nulled out is much more because it includes several circuit boards and metal parts like coils and the ferrite. This is no longer a small amount of metal that has little effect for the detector. And you still find 1.5m detection of a large screen because it is a very sensitive detector. But you see the problem when you take the detector to the field.

Now you no longer have a large monitor to detect. You are looking for tiny signals from the ground. so you turn up the sensitivity and you begin to find a lot of tiny signals from the sky, the ground, from RFI, and other tiny noise. Your signal to noise ratio is poor because you have the metal parts of the boards and ferrite near the search coil. So you expect the small signals to be lost in noise.

But we hear there is magic in this PD. We hear it is necessary to keep the ferrite near the search coil because this is how we will find the treasure signal. We hear how it works for finding gold an more than 30 meters on a lucky day, and we see a video that shows it making beeps from 2 meters. So is there some truth to the idea of putting the ferrite near the omega search coil and nulling it?

Maybe, but I have seen nobody demonstrating any certain success with a PD clone built. I see a video of only the Alonso PD beeping from 2 meters. Why not all the clones?

I already explained about the sensitive part of the omega circuit, and I explained that most clone builders are not careful to keep the circuit boards away from the search coils similar to what you see in the Alonso PD. But there is more:

Not many people listened to Morgan to understand the PD cannot be calibrated at the workbench. This is done outside away from power and other electric noise. And it takes a long time. The trick is to null the ferrite to the omega coil. Some people have special methods for doing this. You remember the Alonso PD has a gap between two ferrite rods, which is different than a single ferrite rod. Adjusting this gap can make some fine tuning adjustments. But the position of the ferrite assembly has a much larger impact on the tuning of the circuit. I suggest you contact other PD builders to learn what they know about successful ways to null the ferrite.

Also, the ferrite material makes a difference. You want a ferrite designed for VLF in the 100 khz range. A ferrite designed for AM broadcast should work fine. But you may be better with a special ferrite that was designed to pick up a clock signal that is broadcast at 60 KHz. These are found in Sony automatic adjusting clocks sold to the American market. If you are using an unknown ferrite, it could be a ferrite that is optimized for the megahertz range and works poorly at Khz, or even attenuates the coil current.

Suppose you get the ferrite nulled so it picks up some kind of metal signal in the field. You still have the sky effect and the wall effect. There is no mystery about these. We know that VLF is absorbed by the ground in an amount that will depend on the conductivity of the ground. More moisture will cause more of the RF to be absorbed. If you hold the coil horizontally, you can expect part of the RF travelling to the ground will be absorbed and part will be absorbed into you because you are standing directly behind the coils and you are conductive for VLF. But as you turn the coil down, you are directing it where more will be absorbed into the ground. Then you turn it up where less of the VLF is absorbed to the ground because it is sent to the sky. We expect the Rx signal to change because the RF load on the TX is changing. And there is also a question of what part of the RF is reflected or refracted in a way that it returns and is picked up by the Rx. If this is happening when the coil is in a horizontal position or pointing down, then pointing it up will not allow the same near-field reflections/refractions to reach the Rx. In any of these directions, your body is usually at the back side of the coils acting as a grounded shield, so the back of the coil cannot make a mirror image of what is seen at the front.

Then we come to the final puzzle: What is the treasure signal?
According to reports, the best of the PDs are nulled in a manner that the sky effect has little impact on the operation, and the locator responds only to gold or silver, with minor amounts of response to aluminum or brass. Apparently these PDs are tuned in a way that has discrimination, and may not be working on a VLF absorption/reflection principle at all. If they are not, then what?

I suppose it does not matter if all you can find is noise in the air at the moment.


Best wishes,
J_P

Hi J_Player
Thanking so much for your good help . as I am saying you are fine engineer
And you pointed to some tip.
All of you said is correct , and I achieve to them by more experiment and
Practice .

About is Alonso PD really work ??? I believe it is work , because , there
Are Movie by Morgan, Andreas, also Geo said , his clone PD work correct .
My built clone PD, so much than sensitive relation to original .as Morgan said
If I remember correct original Alonso PD detect TV screen from 90 cm ,
My PD detect from 1.5 meter easily . tuned null very fine , may be must little
Out of fine null ???? may be if reduce sensitivity , then canceled , sky –ground
Affect . I doing test
Best regards.

[Geo]

Hi J_Player
Thanking so much for your good help . as I am saying you are fine engineer
And you pointed to some tip.
All of you said is correct , and I achieve to them by more experiment and
Practice .

About is Alonso PD really work ??? I believe it is work , because , there
Are Movie by Morgan, Andreas, also Geo said , his clone PD work correct .
My built clone PD, so much than sensitive relation to original .as Morgan said
If I remember correct original Alonso PD detect TV screen from 90 cm ,
My PD detect from 1.5 meter easily . tuned null very fine , may be must little
Out of fine null ???? may be if reduce sensitivity , then canceled , sky –ground
Affect . I doing test
Best regards.

Hi Aft.
In who position do you have the switch when you scan the TV????

Regards

[Geo]

I must be go to electronic market and buy them. Test this,
But I think don’t solve problem !!!! because instability began when
Coil over ground

I use a 7805

[aft_72005]

Hi Aft.
In who position do you have the switch when you scan the TV????

Regards

Hi Geo
Only MD working and power to ferrite receiver was off .
Best regards.

[aft_72005]

I use a 7805

thank you if you having free time also try TL431 , drift is 20ppm , belter than 7805

[Geo]

thank you if you having free time also try TL431 , drift is 20ppm , belter than 7805

No reason. Now is very stamble

[Geo]

Hi Geo
Only MD working and power to ferrite receiver was off .
Best regards.

I never tried it at battery short only as MD
I test it at position for LRL (Ferrite only).

Regards

[FrancoItaly]

Hi All
I think that the secret of Alonzo pistol is mixing 2 signals, one from a side of trasmitting coil and and the second from the other side. A critical adjustement of the signals it allows the detection of long buried targets. In my tests I buried 10 silver coins 10 cm deep and a signal is appeared after few weeks. I don't think that the ferrite is necessary, in my istruments I use only coils of few windings with a resonance of 4 mhz. I think that Alonzo used the ferrite only for an easier coupling with the metal detector. It's also very important the phase relation between the mixed signals, if it's wrong no signal appears...and the pistol is sensitive only to sky/compass/walls... effects. As Esteban says many types of detectors are useful for the purpose, I use a sort of pulse induction mixed with a TR-IB.

Best regards

[Geo]

Hi Aft.
Some good news??????

[aft_72005]

Hi Aft.
Some good news??????

Hi Geo,
I am so busy with other work now , but at first free time I will do some work
For PD.
Best regards.

[Geo]

Hi Geo,
I am so busy with other work now , but at first free time I will do some work
For PD.
Best regards.

I also make some experiments, i will inform you if good news!!!

Regards