Tube coil

[ApBerg]

Hello Ivica,

The wire I used is ca 0.5mm with isolation, made some 75 +75 winding on a pvc tube, the ferrit rod from 10mm fits nice in it. The windings are clockwise and couterclockwise, the fet I use is the irf 9640 (i think) al noting special so far... but the ferrit rod can be the bottle neck ? I have used 20 cm long wave ferrit rods, can tomorrow make some tests with 2 x 10 cm rods..

Also going send you a pm.

Best regards.

Ap

[ivconic]

Pin 6. at NE5534 when ferrite coil is attached:

[ivconic]

Hello Ivica,

The wire I used is ca 0.5mm with isolation, made some 75 +75 winding on a pvc tube, the ferrit rod from 10mm fits nice in it. The windings are clockwise and couterclockwise, the fet I use is the irf 9640 (i think) al noting special so far... but the ferrit rod can be the bottle neck ? I have used 20 cm long wave ferrit rods, can tomorrow make some tests with 2 x 10 cm rods..

Also going send you a pm.

Best regards.

Ap

My ferrite coil is ringing terrible! I tried to match damper resistor.... no way! I changed it from 100 ohms to 820ohms.. no way!
Last one on the photo is 0.48mH. If ferrite pulled half out from PVC - inductance changes to 0.54mH... logical..
I even pulled out ferrite mm per mm while detector was ON and observed scope behavior, no way.. those hums and ringings remains all the time.
Than i replaced TIP125 with IRF9622... same.
Than i connected 20cm round coil = splendid work! Extra depths in air, no ringing..
...
So.. what the hell is going on here!?
I am starting to suspect that ferrite rod?

[ApBerg]

Hello Ivica,

You have the 2 coils on the ferrit rod clock and counterclockwise ?

Made some more photo's and a video that is going on Youtube ..stays there for a a few day's only..
http://www.youtube.com/watch?v=GcwYZsg5F9M
Best regards.

Ap

the screen looking stuff on the pvc tube is double side sticking tape.. not screen..

[bernte_one]

good morning i think a difference is the isolated wire which ApBerg uses
the gaps are higher - other Self Capacitance and Inductance -so other frequency?


http://deepfriedneon.com/tesla_frame6.html

helical coil caculator use points insteads of komma

[ivconic]

Thanks for details!
You haven't measured inductance at your coil?
Wire, is it litz or single inside?

[ivconic]

One more thing that i noticed; if offset is slightly negative adjusted at NE5534 - i get noticeable better detection and behavior on small colored items like coins.
Photo bellow:
a = offset slightly negative,
b = "fuzz", i am wandering if this occurs because we have 2 coils opposite from each other ..or because we use ferrite core with them?

[ApBerg]

Hello Ivica,
You are right... the ferrite is the problem... I have many rod bought on Ebay some time ago... complete worthless !! look http://www.youtube.com/watch?v=jGAlO6jhVPU
so there is some differents in ferrite that we have to find out.
Strange thing.. from the 'good rods' I broke one.. but a small broken rod is also working good.


Is there someone that can explain this ferrite behave ?



Best regards.
Ap

[holyuser]

Hi
These ferrite rods are designed to work in low field with a radio antenna.
It would be better to use a power ferrite type, as in power supplies, in example.
Regards!

[Qiaozhi]

b = "fuzz", i am wandering if this occurs because we have 2 coils opposite from each other ..or because we use ferrite core with them?

Maybe it's the local radio station.

[ApBerg]

Hello Friends,

Have tested all the ferrite I have.... the coil config in the first example works great !
Take some 20 cm long/ 12 mm dia pvc tube, wind 2 coils on this pvc tube from each 75 windings (best some multicore wire 0,5 mm ?) one clockwise and the other on counterclockwise connect them in series.
If you have some ferrite rods ... test it. I have also some 10 cm rods from 10mm dia , if you put this in the pvc tube on one side you have a great pinpointer... 1 euro at the top where the ferrite is .. 15 cm..

Best regards.

Ap

take care if you use the coils without ferrite in it, there is then a large current in the transmitter fet

[ivconic]

Maybe it's the local radio station.

No it's from ferrite, just checked.
Same coil without ferrite is not having "fuzz" on scope...

[silverdog]

Hello Friends,

Have tested all the ferrite I have.... the coil config in the first example works great !
Take some 20 cm long/ 12 mm dia pvc tube, wind 2 coils on this pvc tube from each 75 windings (best some multicore wire 0,5 mm ?) one clockwise and the other on counterclockwise connect them in series.
If you have some ferrite rods ... test it. I have also some 10 cm rods from 10mm dia , if you put this in the pvc tube on one side you have a great pinpointer... 1 euro at the top where the ferrite is .. 15 cm..

Best regards.

Ap

take care if you use the coils without ferrite in it, there is then a large current in the transmitter fet

Hi Ap

it would be interesting to see if the soil allows this distance without too much noise ?

If not then it will be an incredible pinpointer

Silverdog

[lonelyWOLF]

hi...

Here is a different one

[ApBerg]

Hello Friends,


Made some outdoors test..... very very bad.......

.... looks as that the thing is reacting on the eartmagnetic field .. can find the North with it..

So back to start again .. do not make it as I told before.......sorry ...

Best regards.

Ap