AC gaussmeter in static magnetic field

[user079622]

When you shake back and forth AC gaussmeter ,he significantly increase reading(magnetic field), because device is moved in Earth static magnetic field.


Does his acceleration or velocity cause increase in reading and why he even increase reading if magnetic field from Earth is static and constant in magnitude?

I notice, if device is in car, it doesnt mater if I drive 70km/h or 150km/h, so it seems he respond only for acceleration?

 

[berkeman]

What Gaussmeter? Can you post the datasheet or a link to it?

And when you are shaking it, are you careful to keep the angle of the sensor constant with respect to the direction of the Earth's magnetic field? Do you know that direction in your location?

 

[user079622]

What Gaussmeter? Can you post the datasheet or a link to it?

And when you are shaking it, are you careful to keep the angle of the sensor constant with respect to the direction of the Earth's magnetic field? Do you know that direction in your location?

I will put some more information in my first post..

 

[berkeman]

I will put some more information in my first post..

It is generally better to add new information in a new reply. Going back and editing your original post to add more information makes the thread confusing for those who have already started reading/participating in it.

 

[user079622]

It is generally better to add new information in a new reply. Going back and editing your original post to add more information makes the thread confusing for those who have already started reading/participating in it.

OK.

Low frequency analyser: sensor one dimensional
5Hz - 100kHz
measure magnetic (nT) and electric field (V/m)

Of course in one direction device show higher magnetic field numbers, because he has one dimensional sensor.

 

[DaveE]

If the field is uniform (direction and magnitude) withing the areas measured and you don't change the geometry (like tilt the sensor), then no, the B-field reading shouldn't change. Basically you are just measuring the total flux coupled through the area of the sensor, so whatever flux you gain/lose on one side is compensated for by the flux you lose/gain on the other side.

Of course, in practice, you probably won't meet those stipulations. For example, uniform magnetic fields are pretty hard to find except on large scales, like the Earth.

 

[berkeman]

You did not supply the model information or datasheet, but whatever. You do realize that as you are shaking the sensor, you are probably changing the angle of the sensor with respect to the local magnetic field of the Earth, right? You can get the same reading by tilting or rotating the sensor rapidly...

 

[user079622]

You did not supply the model information or datasheet, but whatever. You do realize that as you are shaking the sensor, you are probably changing the angle of the sensor with respect to the local magnetic field of the Earth, right? You can get the same reading by tilting or rotating the sensor rapidly...

If the field is uniform (direction and magnitude) withing the areas measured and you don't change the geometry (like tilt the sensor), then no, the B-field reading shouldn't change. Basically you are just measuring the total flux coupled through the area of the sensor, so whatever flux you gain/lose on one side is compensated for by the flux you lose/gain on the other side.

Of course, in practice, you probably won't meet those stipulations. For example, uniform magnetic fields are pretty hard to find except on large scales, like the Earth.

https://gigahertz-solutions.com/Measurement/Low-Frequency/ME3840B

Yes you are right, tilting sensor rapidly increase reading.

conclusion:
1. So constant velocity of device without tilting the sensor through static Earth magnetic field dont have any influence on reading?

2.Acceleration of device without tilting the sensor in static Earth magnetic field dont have any influence on reading?

 

[DaveE]

https://gigahertz-solutions.com/Measurement/Low-Frequency/ME3840B

Any "medics and alternative practitioners" that use this device aren't going to be treating me or my family. Just saying... YMMV.

 

[berkeman]

Any "medics and alternative practitioners" that use this device aren't going to be treating me or my family. Just saying... YMMV.

LOL, I didn't even look at that datasheet. It looks like it's for measuring LF EM "pollution" -- I'd buy a matching hat if I got one of them.

 

[user079622]

@DaveE
@berkeman

Why would someone use this in medicine??
It's professional device for technicians.

Can strong permanent magnet(static or moving) near the device damage or recalibrate sensor ?

 

[DaveE]

"electrosmog" has a nice BS marketing ring to it. They do have talent, the copy writers.

Anyway, sorry, totally off topic.

Why would someone use this in medicine??

To make money.

Can strong permanent magnet(static or moving) near the device damage or recalibrate sensor ?

Maybe, IDK. How strong? I wouldn't put it in an MRI machine. Ask the manufacturer.

Which BTW, reminds me of another (off topic) story. I was in the hospital at Stanford many many years ago and was supposed to walk around. Anyway my wife and I went into the sub basement corridors and passed a lab door that had a handwritten sign saying don't bring your cell phones inside. We didn't go inside, but her phone was never the same after being near their lab. Massive electrosmog poisoning, I guess.

 

[user079622]

Maybe, IDK. How strong? I wouldn't put it in an MRI machine.

Magnets from sound speaker or from electric motor.

 

[DaveE]

Magnets from sound speaker or from electric motor.

Probably OK unless you are (somehow) inside the motor or speaker. High intensity magnetic fields are hard to make and are mostly contained with magnetic core materials. They don't really want most of their field to escape either.

 

[DaveE]

But, the problem I have with this is the literature you posted was clearly (IMO) written by disingenuous people. So I have no trust in anything else they say. I'm not saying the device is bad, IDK. But the conversation with the manufacturer is definitely broken from an engineer's perspective. We have no idea what that thing actually is.

 

[user079622]

Probably OK unless you are (somehow) inside the motor or speaker. High intensity magnetic fields are hard to make and are mostly contained with magnetic core materials. They don't really want most of their field to escape either.

But this sensor measure only to 2000nT, this is so much smaller even from Earth field, so I thought every higher mag. field could damage sensor or recalibrate...

 

[DaveE]

But this sensor measure only to 2000nT, this is so much smaller even from Earth field, so I thought every higher mag. field could damage sensor or recalibrate...

You can't tell damage thresholds from the sensitivity/range specifications. It is almost universally common for EEs to design various types of overload protection into their stuff. It has a CE mark, so I would guess it was (should have been) tested with some pretty strong RF magnetic fields for EMC immunity.

 

[Vanadium 50]

It's professional device for technicians.

Not according to the link you posted. That page is filled with quackery.

I think you need to start taking this more seriously. Not only is this device's page filled with quackery, but you need to read your own spec sheet. The sensitivity is claimed to be 1 nT. The earth's field is around 6000 nT. Therefore, it can register a tilt of 0.01 degrees. I challenge you to hold it this steady.

(I very much doubt that the nT sensitivity is right)

 

[user079622]

You can't tell damage thresholds from the sensitivity/range specifications. It is almost universally common for EEs to design various types of overload protection into their stuff. It has a CE mark, so I would guess it was (should have been) tested with some pretty strong RF magnetic fields for EMC immunity.

Ok thanks for information.

So tilting the sensor in static mag. field has same effect just like static sensor is in changing magnetic field?

 

[user079622]

Not according to the link you posted. That page is filled with quackery.

I think you need to start taking this more seriously. Not only is this device's page filled with quackery, but you need to read your own spec sheet. The sensitivity is claimed to be 1 nT. The earth's field is around 6000 nT. Therefore, it can register a tilt of 0.01 degrees. I challenge you to hold it this steady.

(I very much doubt that the nT sensitivity is right)

Magnetic flux range is from 1-1999nT, so 1999 is max number that you can measure.
What I wrote wrong?

 

[Vanadium 50]

The Earth's field is ~60000 nT. (I miswrote 6000 above). If your meter won't measure about 1999 nT it won't work anywhere on the planet.

 

[berkeman]

LOL, I didn't even look at that datasheet. It looks like it's for measuring LF EM "pollution" -- I'd buy a matching hat if I got one of them.

And it contains statements like this:

Many patents have been granted to us, the devices have tenthousandfold proven their reliability, and have shown to be leading-edge in their price categories.

Hoo boy. Okay, this thread is closed, and I'm going to go buy/make that hat.