Off the shelf loop antenna for frequencies < 1kHz

[Wallace Gasiewicz]

RoV:
Sorry, I meant  to refer to the solenoids, your answer is appreciated

Thanks

[coppercone2]

they do this with electrets too though. Just hard to get that, produced with particle accelerator I believe.

[LM21]

Would ferrite bars work? They are good for little higher frequencies. I don't think they are very efficient, but what is at 1kHz. Off the self? 20km/miles of barbed wire fence?

[radiolistener]

Would ferrite bars work?

yes, but if you're planning to use it for transmitter it will be a bad choice, because ferrite core enters into saturated state at relative low power level.

For receiver it works very good.

[Marco]

yes, but if you're planning to use it for transmitter it will be a bad choice, because ferrite core enters into saturated state at relative low power level.

The field however won't be much different from a permanent magnet of the same size. The only thing the spinning magnet has over it, is that it's less alignment sensitive at the receiver (still highly alignment sensitive, just along one less axis). Good luck transmitting any data though.

Would a pulsed air core be the best for inductive communication?

[LM21]

Would ferrite bars work?

yes, but if you're planning to use it for transmitter it will be a bad choice, because ferrite core enters into saturated state at relative low power level.

For receiver it works very good.

If most of the magnetic circuit is air, I wonder if saturation is a problem. Small size is a larger problem, I think. But I'm not an expert here, so I am happy to hear data or experience about radiation.

[radiolistener]

Smaller size of radiator requires higher field strength in order to compensate smaller size.

Ferrite core antenna uses resonance effect in order to accumulate energy of field strength oscillations for a specific resonant frequency. The same effect happens when small size resonant antenna working for transmission.


Regarding to rotating magnet, if it has high enough field strength, you will be able to listen it on receiver. But the problem here is that it will produce clean carrier (clean sine). It will be hard to apply modulation for a rotating magnet.

[f4eru]

easy as buying a 2 meter long flat bar aluminum from home depot and bending it around a barrel or something

At that point it's really really easier to just get an aluminium rim from a junk bicycle, remove the rest of the wheel, and open it at the junction.

[coppercone2]

oh yeah thats a great idea actually. Bending is a useful skill to know but a bicycle wheel is 500x easier and also much stronger.