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Omni-direction pickup coil?

  • Thread starter Thomas Shaeffer
  • Start date
T

Thomas Shaeffer

Jan 1, 1970
0
I need to acquire an average reading for 60Hz EMR on all vectors
within a room-size area.

I want a single sensing coil with no directional bias, rather than one
for each axis.

Is there any type of winding that would be best suited to this?

Preferably something with no particular directional senstivity.

Would a core material be advisable? If so, how would it be worked in?

Any ideas?

Thomas
 
M

Mike Page

Jan 1, 1970
0
Thomas said:
I need to acquire an average reading for 60Hz EMR on all vectors
within a room-size area.

I want a single sensing coil with no directional bias, rather than one
for each axis.

Is there any type of winding that would be best suited to this?

Preferably something with no particular directional senstivity.

Would a core material be advisable? If so, how would it be worked in?

Any ideas?

Thomas

Were you thinking to use ferrite to gather the flux and direct it
through a single coil? Sounds like a lot of design work, which might
ultimately not work. Why not 3 coils, or one slowly rotating one?

Regards,
Mike.
 
I

Ian Stirling

Jan 1, 1970
0
Thomas Shaeffer said:
I need to acquire an average reading for 60Hz EMR on all vectors
within a room-size area.

I want a single sensing coil with no directional bias, rather than one
for each axis.

This is impossible, for a coil with no active parts.

The problem is analgous to trying to smooth a furry ball, where you cannot
get it smooth all the way round, you end up with tufts.

A basic coil has a null when the field is at right angles to the maximum
sensitivity.
For any arrangement of coils, you'r going to get nulls.

One way to do this would be to use a container of fluid as the magnetic
sensor, and a proton precession magnetometer coil round it to sense
the changes in magnetic field.
However, this won't really work very well without extraordinary efforts.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Ken Smith
A toroid works too. Thats how Varian did it in the early days.

How can you make an omnidirectional magnetic antenna from a single
toroid?

I think the simplest solution for the OP is to first realise that there
can be only one unique, resultant direction of the magnetic field at any
point. You find this direction, and then the strength of the field, by
turning a single coil in two planes until you get maximum response. This
is much easier than trying to synthesise an omnidirectional antenna,
which gives you only strength and not direction, anyway.
 
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