Parameters for IB coil

[Tinkerer]

I would like to define the parameters of an IB coil, designed for us all the test and experiment with a discriminating PI design.

Diameter?
Inductance?
DC resistance?
Max coil current?
Other parameters?

Suggestions are welcome.
Let's see if we can agree on the parameters so that we can all build the same coils.

Tinkerer

[simonbaker]

Great idea!

[Max]

I would like to define the parameters of an IB coil, designed for us all the test and experiment with a discriminating PI design.

Diameter?
Inductance?
DC resistance?
Max coil current?
Other parameters?

Suggestions are welcome.
Let's see if we can agree on the parameters so that we can all build the same coils.

Tinkerer

Some I think could be useful...

wire material
wire diameter
wire weight per lenght unit
conductivity
insulant properties (thickness, dielectric params etc)


Kind regards,
Max

[Qiaozhi]

I would like to define the parameters of an IB coil, designed for us all the test and experiment with a discriminating PI design.

Diameter?
Inductance?
DC resistance?
Max coil current?
Other parameters?

Suggestions are welcome.
Let's see if we can agree on the parameters so that we can all build the same coils.

Tinkerer

Since this an IB setup, you will also need to define the phase relationship between the two coils. Otherwise no two setups will be the same, regardless of inductance, resistance, wire type, etc.

[Tinkerer]

Since this an IB setup, you will also need to define the phase relationship between the two coils. Otherwise no two setups will be the same, regardless of inductance, resistance, wire type, etc.

Very good suggestion.
The phase relationship is very important.
The interesting thing is that the method works with different phase relationships.
The choice of the relationship will enhance certain features in that it enhances some types of response and attenuates other types of response.

Materials:
This is a difficult subject. Access to electronic parts and even simple hook-up wire is very difficult for me here.
So I have had to invent ways to do with what I have at hand, string, nails sand down old starter motor brushes for a graphite shield etc.
It would not be reasonable to expect everybody to repeat all that.

So I suggest that we leave the parameters a bit loose.
Maybe +/- 10%

We might learn more from the results if we use a certain variety in the parameters.

Tinkerer

[simonbaker]

Very good suggestion.
The phase relationship is very important.
The interesting thing is that the method works with different phase relationships.
The choice of the relationship will enhance certain features in that it enhances some types of response and attenuates other types of response.

Materials:
This is a difficult subject. Access to electronic parts and even simple hook-up wire is very difficult for me here.
So I have had to invent ways to do with what I have at hand, string, nails sand down old starter motor brushes for a graphite shield etc.
It would not be reasonable to expect everybody to repeat all that.

So I suggest that we leave the parameters a bit loose.
Maybe +/- 10%

We might learn more from the results if we use a certain variety in the parameters.

Tinkerer

Yes, loose is realistic. But each person should give details of their setup so maybe we can see why different results if that happens.

I think a major difficulty we have is because of the way the forum threads force us to move forward and it is very difficult to maintain a picture or reference that we are discussing. Essentially we need a "whiteboard" with the topic on it and diagrams. Otherwise, people throw in this and that and half the time talking about different subjects completely. Fun, but crazy sometimes.

I don't know how to solve that. Every thread needs a popup window with a static whiteboard with info that we can update as we go somehow. It should have a history also so you can go back to a message and see what the whiteboard looked like at that time. Aach, too complicated...

Cheers!

-SB

[Tinkerer]

Yes, loose is realistic. But each person should give details of their setup so maybe we can see why different results if that happens.

I think a major difficulty we have is because of the way the forum threads force us to move forward and it is very difficult to maintain a picture or reference that we are discussing. Essentially we need a "whiteboard" with the topic on it and diagrams. Otherwise, people throw in this and that and half the time talking about different subjects completely. Fun, but crazy sometimes.

I don't know how to solve that. Every thread needs a popup window with a static whiteboard with info that we can update as we go somehow. It should have a history also so you can go back to a message and see what the whiteboard looked like at that time. Aach, too complicated...

Cheers!

-SB

So let's get started:

Tx coil
Outer coil diameter .................280mm
300uH
1 Ohm DC resistance

RX coil
Outer diameter ...................120 to 200mm
300 to 450uH
5 Ohm DC resistance

Bucking coil

Outer diameter ...............110 to 220mm
2 Ohm DC resistance

The parameters measured with 4 to 6 feet of cable included

Feedback please

Tinkerer

[simonbaker]

So let's get started:

Tx coil
Outer coil diameter .................280mm
300uH
1 Ohm DC resistance

RX coil
Outer diameter ...................120 to 200mm
300 to 450uH
5 Ohm DC resistance

Bucking coil

Outer diameter ...............110 to 220mm
2 Ohm DC resistance

The parameters measured with 4 to 6 feet of cable included

Feedback please

Tinkerer

Can you give number of windings in each coil and wire gauge?

How do you null your coils?

Regards,

-SB

[Tinkerer]

Can you give number of windings in each coil and wire gauge?

How do you null your coils?

Regards,

-SB

The number of windings will depend on the relationship between the fill factor and inductance. I will try to explain:
For a 280mm diameter coil, 20 turns of magnet wire, tightly packed may give an induction of 300uH.
But if you have a wire that has 1mm insulation, the same 20 turns will give less than 300uH, because there is more space between the wires.
I use MiscEl to do the calculation. Calculating with 1mm wire will give so many turns and so many meters.
Then calculating with 3mm wire, 1mm copper and 2mm insulation, will give a different number of meters.
My last coil has 21 meters of wire and a fill factor of about 20%, the exact numbers are in the thread: Coil with polypropylene spacer.

I wind the 3 coils separately and take a lead, coax or shielded twisted pair to the PCB.
Otherwise follow the instructions given by David Emery.

I have posted a link for AWG wire gauge a few days ago. It shows the relationship between the gauge, the resistance and the length of wire.

Tinkerer

[simonbaker]

The number of windings will depend on the relationship between the fill factor and inductance. I will try to explain:
For a 280mm diameter coil, 20 turns of magnet wire, tightly packed may give an induction of 300uH.
But if you have a wire that has 1mm insulation, the same 20 turns will give less than 300uH, because there is more space between the wires.
I use MiscEl to do the calculation. Calculating with 1mm wire will give so many turns and so many meters.
Then calculating with 3mm wire, 1mm copper and 2mm insulation, will give a different number of meters.
My last coil has 21 meters of wire and a fill factor of about 20%, the exact numbers are in the thread: Coil with polypropylene spacer.

I wind the 3 coils separately and take a lead, coax or shielded twisted pair to the PCB.
Otherwise follow the instructions given by David Emery.

I have posted a link for AWG wire gauge a few days ago. It shows the relationship between the gauge, the resistance and the length of wire.

Tinkerer

Ok. How about a typical number with a typical wire type?

How do you null your concentric coil?

Regards,

-SB

[Tinkerer]

Ok. How about a typical number with a typical wire type?

How do you null your concentric coil?

Regards,

-SB

Try AWG 18 with insulation, 21 meters for TX, 280mm diameter
AWG 27 with insulation, also 21 meters for RX, 150mm diameter
About 6 to 10 turns of AWG insulated for Bucking coil, 150diameter

http://www.geotech1.com/pages/metdet...planar_300.pdf

See instructions for nulling. Fine tuning will be done on the PCB.
Remember for fine tuning on the PCB the Bucking coil needs to have its own leads to the PCB.
I will take photos tomorrow of my experimenting coil setup. It can be dismantled and the wire reused.

Tinkerer