Turbo-charging a coil

[tom_pay]

Hi,

For a project I am working on, I would like to get a coil and get the most amount of EM out of it. I would appreciate some advice on how to get it extra powerful. Does anyone know how to turbo-charge a coil?

I understand that I must make a 'tank' circuit with a capacitor and resonant frequencies, however I would like to do more and get it really powerful.

Thanks, in advance

Tom

 

[Sceadwian]

You need to be a lot more specific about the frequencies and uses you're interested in,

 

[tom_pay]

Sorry,

I was going to use approximately 1000 turns of 0.25mm enameled copper wire around a ferrite rod core. The resonant frequency would, ideally be around 1.3 kHz.

The type of core material can easily be changed, however their physical size and resonant frequency, I would like to keep remotely constant. However if it will greatly increase the EM output, the resonant frequency can be changed.

I am trying to send a pulse from one coil to another, so that the receiving coil can roughly locate the transmitter coil. Hopefully the distance between the two coils will be about 50m.

Thanks

Tom

 

[user_88]

I seem to recall a reference to the attenuation of magnetic fields ... There is a factor of
1/R² involved ... see Richard Feynman: Physics Lectures for example.

At a distance of 50 m, your initial concept would seem impractical, as far as a magnetic field is concerned, even with tuned resonant circuits.

However, if you were to use the electric field, utilizing transmitting and receiving antennas, you should be able to get something to work. The E field attenuates at a factor of only 1/R ... which is a significant enough difference to permit radio transmission over long distances.

 

[tom_pay]

However, if you were to use the electric field, utilizing transmitting and receiving antennas, you should be able to get something to work. The E field attenuates at a factor of only 1/R ... which is a significant enough difference to permit radio transmission over long distances.

Hi,

Thank-you very much for your idea user_88, I will certainly explore it some more, however I have some questions, sorry.

I'm not quite sure on electric fields, but to create a good one, would I just increase the voltage of my LC circuit by using a driver coil, a few coils around the main coil?

Would the receiving coil/setup be the same?

Thanks,

Tom

 

[Sceadwian]

What degree of location sensitivity do you need?

 

[tom_pay]

As much as possible really, anywhere in a 5m radius is fine, if I'm being too optimistic, please tell me!!!

Tom

 

[Sceadwian]

I was going to use approximately 1000 turns of 0.25mm enameled copper wire around a ferrite rod core.

That will be VERY directional.
You could triangulate it, but using an array of multi directional atennas that broadcast bursts out of turn and observe the signal strength on the receiving antenna, but that's... complicated!

 

[tom_pay]

Hi

The whole thing is designed to have a transmitting coil placed approximately 50m underground in a complex cave system, the transmitter coil then must find the transmitter coil to map and explore the cave system.

The very directional aspect will be good, wont it? Giving a more accurate location on the surface.

Sorry if I have been a bit vague.

Tom

 

[elsa tobin]

 

[Sceadwian]

Only if you have a dozen triangulated and known transmitting stations that don't overlap, and a DAMN good receiver. How do you think GPS works? All the same rules apply. Spatial determination is incredibly difficult, even on a 5 meter range, and it's virtually voided in a complex cave system due to
the environmental impact of the received signal vs the possible alignment with transmitters...

A modern GPS system can do pretty good, FREE AIR to ORBIT, the attenuation of RF even low frequency (which exponentially decreases resolution) through rock... 5 meters is more than pushing it. All it takes is a SINGLE nugget of metallic deposit to blank out reception for hundreds of meters.

 

[tom_pay]

I know for a fact that this design works, I have seen it and used it.

I my only question to improve this design.

 

[Sceadwian]

Fully describe the design you've used and seen. Full schematics including the antenna arrays used.

 

[tom_pay]

Two coils ~100 turns each 10m apart.

Transmitter:
Square wave oscillator at LC resonant freq, directly driving the LC circuit.

Receiver:
Basic op amp amplifier driving a set of headphones.

I no longer have the diagrams as my computer recently crashed.

Tom

 

[shortbus=]

Only if you have a dozen triangulated and known transmitting stations that don't overlap, and a DAMN good receiver. How do you think GPS works? All the same rules apply. Spatial determination is incredibly difficult, even on a 5 meter range, and it's virtually voided in a complex cave system due to
the environmental impact of the received signal vs the possible alignment with transmitters...

A modern GPS system can do pretty good, FREE AIR to ORBIT, the attenuation of RF even low frequency (which exponentially decreases resolution) through rock... 5 meters is more than pushing it. All it takes is a SINGLE nugget of metallic deposit to blank out reception for hundreds of meters.

While its going to be beyond the OP, the limit to GPS underground is much, much more than that They drilled a 'directional' gas well on my property a few years back and used a GPS based instrument every so often to make sure it was going where the wanted it to. Over 2500 feet underground.

 

[Sceadwian]

shortbus, I can certifiably guarantee that whatever the device they used 2500 feet underground was not directly GPS based....

A thick piece of cardboard will block a GPS signal... Whatever device they took measurements from beyond that is proprietary to the GPS system.

 

[JimB]

Whatever device they took measurements from beyond that is proprietary to the GPS system.

Probably inertial navigation, using accelerometers and a gyroscope.

JimB

 

[shortbus=]

Well if it wasn't GPS the guy lied to me! He had a monitor in the van that showed the out put from five satellites in orbit compared to the sensor location.

 

[Sceadwian]

showed the out put from five satellites in orbit compared to the sensor location.

So? That's just the final output, he didn't show you under the hood at how those measurements are derived, he didn't lie, you assumed the readings were direct.

 

[carbonzit]

Well, wouldn't there have to be some kind of (radio) link between the device and the GPS satellites in order for the system to work? How else could it know the location of the device?