Zahori

[nelson]

OK Morgan, but what about the kind of sound and how to set up the 3 potenciometers?
Regards?
Nelson

Yes,nice and cheap project,this save your wallet from expensive MINEORO and other LRL´s in the market. Results will be the same(or better) and you save you money.

Happy hunting

[Morgan]

zahori

OK Morgan, but what about the kind of sound and how to set up the 3 potenciometers?
Regards?
Nelson

R9 midle pot.

R8,R10 play with them near TV until get the best distance.
Not forget my Zahori was connected to BFO,was diferent from your

[nelson]

Ok Morgan, son can you show me how to add the BFO and i assume that the BFO allow you to tune the detector on some frequency spectrum?
Thanks for the pictures and , don´t forget to tell me if the 2N3819 legs are connected corect has is show on my previus pictures.
Take care and have a nice day Morgan
Best regards
Nelson

R9 midle pot.

R8,R10 play with them near TV until get the best distance.
Not forget my Zahori was connected to BFO,was diferent from your

[ATTACH]14657[/ATTACH]

[ATTACH]14658[/ATTACH]

[ATTACH]14659[/ATTACH]

[bama]

test results on Zahori

Hi everyone, are there any good field test results on the Zahori and mini
Zahori? It would be nice and helpful to hear from those who have built
these LRLs. thanks,
bama

[Morgan]

zahori

Ok Morgan, son can you show me how to add the BFO and i assume that the BFO allow you to tune the detector on some frequency spectrum?
Thanks for the pictures and , don´t forget to tell me if the 2N3819 legs are connected corect has is show on my previus pictures.
Take care and have a nice day Morgan
Best regards
Nelson

No need to adapt the BFO,it make the Zahori more complicated.
The pins are correct in your PCB.

[nelson]

Ok Morgan and thanks
So i will made another antenna, but with less wire thicknes
To the rest of entusiasts about mini zahori, can you share your expirencies, like how to test it, what sounds should i spect from it, etc.
Regands
Nelson

No need to adapt the BFO,it make the Zahori more complicated.
The pins are correct in your PCB.

[g-sani]

If you mean switching off CRT TV then "switch off" mean nothing. Residual static voltage of CRT can be prolonged for hours. If you open TV and try to touch CRT shielding with your finger after "switch off" you can sense this voltage way better than your Zahori (almost unforgetable).

I am asking this WM6 thinking of the AC mains.
May be we detect this as well when the set is on.

[WM6]

I am asking this WM6 thinking of the AC mains.
May be we detect this as well when the set is on.

AC mains voltage remain too in TV after turn TV OFF, but this voltage is not so high as voltage at CRTs High Voltage Anode made in form of shielding. This voltage remain long after turn TV OFF. This is explanation why you can sense CRT after turn TV OFF.

[g-sani]

Hi WM6, so you say that having the TV set on or off makes no difference and the test still the same.

[WM6]

Hi WM6, so you say that having the TV set on or off makes no difference and the test still the same.

Yes if you use a static voltage detector (what Zahori is) and switch TV set between ON and OFF.

If you let TV to stay at OFF position for hours or days then you evidently sense a difference (how much time we need to CRT High Voltage disappear depend on CRT construction).

You can try this by yourself, turn CRT TV OFF (mains plug out of mains line!!!), open it and touch High Voltage Anode on CRT. You get in moment possibilities to singing Rigoletto.

[J_Player]

Hi g-sani,

Here is an explanation that may make it easier to understand how to use a CRT for detecting static fields:

The high voltage anode charges a conductive parts inside the glass picture tube which can hold this charge for some time after the power connector is removed from the mains supply. A picture tube will charge to many thousands of volts, and will act as a capacitor because of the glass layer that separates the positive charge inside the glass tube from the more negative parts and grounded parts outside the tube. This charge is supplied from a high voltage flyback transformer that feeds to the anode wire. The high voltage passes through the side of the glass CRT tube where the anode is connected to a conductor that penetrates to the inside of the tube and charges conductive parts inside. There is a grounded shield around this glass tube, except at the front face of the tube which is open to the air. The open face of this tube can collect a large static charge that sometimes can be seen to make a snapping static discharge noise when you touch it after turning off the power. If you are using your Zahori to detect static charge anomalies in the air, then you should see a large anomaly near the face of a CRT from an old computer or television. The larger screens usually have higher voltage charges, and are expected to cause a larger anomaly in the air than a smaller CRT.

You can discharge a CRT high voltage by first removing the power plug from the mains supply and opening the rear enclosure. Then you can connect a wire from the ground of the TV to a screwdriver, and slip the screwdriver under the insulator that covers the anode wire until it touches the conductor. You may hear a snap noise if the voltage is high enough to make a spark. Be careful not to touch anything metallic while discharging the CRT tube. You can hold the insulated part of the screwdriver handle to be safe. Some designs of CRT use a high value bleeding resistor designed to slowly discharge the CRT after the power is removed from the charging circuit. But do not count on one of these resistors to remove the high voltage from inside the CRT.

If you have discharged the CRT, then the only charge remaining will be charges that are stored in capacitors in the TV circuit board. (Remember you disconnected the power plug from the mains before discharging the CRT, so there is no longer any mains power in this TV to sense). If you plug in the power plug without turning on the CRT, then the mains power should be the largest power that maybe you can detect using a Zahori near the power cord and the TV switch and other parts of the circuit board. Some CRTs keep "sleeping" circuits powered when the power is switched to the off position, that will not power up the CRT. Other CRTs may charge the CRT during the turned-off "sleeping mode".

The answer to your question is:
You can detect the electric field around a CRT whether it is switched on or off, or even if it is unplugged, depending on the conditions.

Here is a list of conditions that show the expected response:

1. Power turned on to see an image on the screen:
High voltage DC field at the screen with small AC component, and also a lower voltage AC field in the circuit board and power chord. You should be able to detect maximum electric field near the CRT face in this condition.

2. Power turned off after seeing an image on the screen:
High voltage DC field at the screen with out any AC component, and also a lower voltage AC field in the circuit board and power chord.The CRT static voltage will eventually leak and discharge over some minutes, or maybe some days depending on the leakage paths. So you will see a strong electric field in front of the CRT at the time it is on which will continue after you turn off the power. After the power is switched off, you will see the high voltage field eventually deteriorate until you can only sense the mains power in the circuit board and power chord. *The exception is for CRTs which have a sleep mode that keeps the CRT charged and ready for instant playing -- These will continue to have a large electric field anomaly after switching the CRT off.

3. Power plug removed from mains after seeing an image on the screen:
High voltage DC field at the screen only with NO AC component. There will be no AC components and no sign of AC voltage from the circuit board or power chord, because the AC mains power was removed. Possibly some small static voltages will be stored in capacitors on the circuit board, but these are small compared to the CRT voltage. The CRT static voltage will eventually leak and discharge over some minutes, or maybe some days depending on the leakage paths.

People who built the Zahori say it is good for detecting static fields. They report they can detect mains power and electrical transmission lines, and sources of static charge like CRTs and ion generators. I doubt you will be able to locate low voltages that may be stored in capacitors on the circuit boards. But you should be able to detect any strange anomalies to the electric field in the air (maybe over 50 volts or more, depending on how sensitive your circuit is set).

Hope that helped,
Best wishes,
J_P

[g-sani]

Thanks for explaining to both WM6 and J_P.
I think I understand.

[nelson]

Hi

Yesterday i made some test with mini zahori and it can detect my home electrical power lines on the wall about 8 to 15 centimeters away from the wall.
The sound comming from the buzzer of course is current but not a beep.
I also tested the unit in front of my old TV set and it detect current from just about 30 or 40 centimeters, no more than that.
My questions now are:

1.- Modifing my antenna could get more sensitive?
The distance fom L1 to L2 is important and if so what is the correct disctande. Mine has a distance of 0,5 cms?

2.- MY antenna wire is 1.6 mm in diameter, what is the best wire gauge that probes to work better?

3.- The first time i build mini zahori i placed 2N3819 reversed and seems to work to, but now i conecter the rigth way. So i whant to know if this could burn my 2N3819? This is important to know, cause this may cause my detector to work poorly.?

I hope someone with more knolegments and expirence can help, cause i m realy enthusiastic about this experiments.

Thanks and best regards
Nelson

R9 midle pot.

R8,R10 play with them near TV until get the best distance.
Not forget my Zahori was connected to BFO,was diferent from your

[ATTACH]14657[/ATTACH]

[ATTACH]14658[/ATTACH]

[ATTACH]14659[/ATTACH]

[g-sani]

Are we also measuring DC static fields whith the zaxori?

[nelson]

Hi.
By now i think it measures just AC current, cause i haven´t the oportunity to measure other divices and other fileds.
Regards
Nelson

Are we also measuring DC static fields whith the zaxori?