EMF Detector made easy?

Hello one and all.

I have been looking into building a "very" sensitive EMF detector due to issues with power lines in the area. I am sorry to say that I have no REAL idea on how to do it. I was also told that there is a way to build a device that would use Hall effect sensors to measure the earths magnetic field. It would be much more sensitive and would work if adjustable. I have yet to find a circuit design that will give a visual as well as audible measurement. An LED bar graph would be ok. Any good ideas on what I could build that would do this?

Thanks for your help.

Bryan

"Larry Brasfield" wrote in message news:65l_d.31$ snipped-for-privacy@news.uswest.net...

Just to help promote this approach ahead of the other (as yet unseen) contenders ...

With a little extra complexity in the coil and a few switches, it could also provide an arrow to indicate which direction the irradiated user ought to run. Otherwise, given the usual arrangements in the vicinity of power lines, he might run without gaining any *real* benefit from the effort.

REAL

Hall

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design

to

REAL

Hall

more

design

graph

It's not difficult to build, you an use a ferrite loopstick with a lot of fine wire wound on it as the sensing probe. One of these is here.

Here's a meter using Hall effect sensors.

The big difficulty is calibrating it to a known standard. And they are not that expensive so there is no point in building one yourself. There are several companies that offer a calibrated EMF measurement meter for under a hundred dollars. Here's one with LEDs for under $25. Also the cellsensor mentioned below.

Two other inexpensive meters mentioned in a paragraph from a story found with google: "I brought an am radio to the office and it would be very noisy in that office but not in the other rooms and really bad near the wall and ceiling. I then went out and bought an emf meter (cellsensor, analog meter, single axis, $42.00) and measured very high readings only in that office and the hallway. It would blink and beep like crazy even on the high setting. I did much research and talked to other engineer friends who tell me it is unconceivable to have that much emf. So I bought a digital emf meter (A.W. Sperry EMF-200A, single axis, $60.00) and proved it. I was getting over 199 mg at the wall about 2" from the conduit behind sheetrock. It went off the scale about an inch from the wall."

to start, think about this

do you want to measure the ELECTRIC field at 60 Hz?

or

do you want to measure the MAGNETIC field at 60 Hz?

that is two completly different measurments.

Measuring an electomagnetic field implies you are in the far field meaning you are many wavelengths away from the source which at 60 Hz is several miles.

Mark

Google "Fluxgate magnetic"

-Robert Scott Ypsilanti, Michigan

I read in sci.electronics.design that Mark wrote (in ) about 'EMF Detector made easy?', on Thu, 17 Mar 2005:

Absolutely. The OP clearly understands so little about the subject that advice on making a detector is futile.

For 55 Hz, the distance is approximately 1000 km.

due to

no REAL

GASP! You mean those strawberries we eat have been irradiated?!? Don't let the organic nuts know!

People don't realize how much of an electrostatic field there is around those high tension lines. But it rapidly dissipates after a few scores of feet.

A Proton Magnetometer for entertainment/nerd value or a Flux-Gate can measure the magnetic field component - *what for* and *how to calibrate* is for the user.

Maybe easiest to buy?

The Electric component can be seen in the dark when holding a flourescent tube at one end and the other closer to the wires - The 440 kV "SuperGrid" crossing Didcot, UK will light up the tube a fair bit.

I did the experiment after getting small chocks while carrying a well-insulated child in a Nylon suit on my shoulders below the wires whenever child touched my head.

Anyway - Electrometer is the word, I think.

My girlfriend and I were once driving down a road with lots of high-tension lines above..(Going down LoLo Pass,on Mt.Hood,in Oregon,the wires were coming from the Bonneville dam.) And with the sun-roof open we could hear them hissing and buzzing.. We noticed after a while we felt kind of "odd"..not really dizzy but,"wierd-headed".. We both noticed it,and I commented to her about it,and she had noticed it about the same time.. The lines are pretty dang low in some places,I probably could have stood out of the sunroof,and raised my arm,and got an arc to jump to me,they're only like 15-20 feet overhead in places!! Wierd stuff.

the

Don't

around

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Oregon,the

stood

You were probably deceived by the lack of something to compare them to, and they were much higher than 20 feet. There is something like 800 feet between towers, and the lines can sag somewhat, but they have to be certain heights above ground because of the high voltages, which can be a half million volts. The humdity in the air makes the crackling louder, but there's always some corona discharge when the voltages are that high.

Check this out. Click on BIG Arcs and Sparks and D/L one and view it.

why do you think it was the HT lines?

maybe you should check your car for CO

Mark

Yea,they probably were higher than 20 feet,but MAN they look LOW.. It's funny when you see the wires up close,and realise that the "little" cables up there are like 4 inches diameter! (and there's 3 cables per conductor/phase,connected together with Y shaped pieces.) and those long glass insulators they're hanging from..they must be like 10 feet long!

The crackling/hissing/buzzing noises are kinda freaky. I should go up there and take pics,or video or something.. It's a creepy place! Desolate gravel "pits" on the side of the road,where people shoot off guns,and dump rubbish..

I read in sci.electronics.design that Watson A.Name - "Watt Sun, the Dark Remover" wrote (in ) about 'EMF Detector made easy?', on Sun, 20 Mar 2005:

How close do you get to the overhead cables at the train station? Very close, in UK (3 m minimum, I believe) and they have 25 kV 50 Hz on them.

have

noticed

to,

"little"

The high tension lines that terminate here locally in a huge switchyard come across the desert and mountains from Hoover dam and Lake Mead. They were adding more conductors and the new ones were laying on the ground, so I went over to the fence to check them out. They were about

to be

be

are

it.

That's a fine piece of writing. Sounds like the first sentence of a good novel.

Interesting technical information followed too.