This reminds me of two evens from my past. 1. Back in the 70's home siding and window salesmen went door to door offering a free home energy analysis. Using a hand held device, the meter would increase as they walked toward a window showing the loss of energy. In fact, the meter was a Light Meter used by photographers. People are so gullible.
2. Again some years back, people were all freaked out about microwave ovens. A customer of ours purchased a hand held microwave detector (with meter movement) to measure the microwave fields leaking out of their ovens in all the employee break rooms. Our company sold them an unrelated device (carbon analyzer) that had a small electrode heater which emits a magnetic field at line frequency. Someone put the Microwave Meter next to our product and the meter jumped all over the place. They had a fit thinking that our product was emitting microwaves and they would not accept our explanation that the meter movement was just being screwed with by the magnetic field. BTW, I'm looking for a "Global Warming Meter" if anyone knows where I can get one. :o) The other Brian PS: The sense of humor displayed by some of the people on this email group really makes my day. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ken Javor Sent: Thursday, February 03, 2011 4:49 PM To: Untitled Subject: Re: Gauss Meter recommendation If I lived in a state on the brink of bankruptcy, and falling into the Pacific, I might have trouble sleeping as well, but it's a bit of a stretch to blame insomnia on overhead power lines. It might not be much of a stretch to say that the reason CA is on the brink of bankruptcy is a populace that loses sleep and blames it on such minutiae. OTOH, if I lived out there and could make money off it, I might be a little more charitable. Mencken said no one ever went broke underestimating the intelligence of the American people, and I believe it was PT Barnum who said a sucker is born every minute. So my crankiness is likely just due to the fact that I'm not cleaning up on all the idiocy out there. Having said all that, if you were going to use a spectrum analyzer, you would need one that went down to power line frequencies. These tend to be more expensive than the garden variety kind that start at 9 kHz. And a biconical antenna is not your transducer of choice. You are looking at a handheld coil here. You need to have some kind of assessment of what you expect to see, because different meters cover different field intensities, and you need one optimized for what you want. Most EMF meters don't feed an external device, they just give a number, which purports to be the magnetic field from the power line. Ideally it would be a broadband device that would cover the power frequency and lots of harmonics, so you can say you are measuring everything out there. It isn't immediately obvious you need to break down the spectrum of power frequency and individual harmonics, unless the latest "study" shows that humans are particularly susceptible to a particular frequency or set of frequencies. When you get all done measuring the fields from the overheads, place the meter next to an appliance the home dwellers might spend some time around. My mother has a forty or fifty year old clock that is an electric motor that runs off the power mains. You set a meter next to it and it will bury the needle every time. Have fun - freak people out. Oh, yeah, you were actually looking for useful advice. You can put emf meter into a search engine and find any number of devices which are good enough for the purpose. They are likely useless, but as I said, good enough for the purpose. If you want a real meter, Walker Scientific makes these. Others do as well, but I'm familiar with Walker. One type of meter works on the principle of a loop driving an impedance much lower than that of the loop itself. The meter measures current out of the loop into the low impedance. If you do the math, you will see that the current level is proportional to the magnetic field, but is frequency--independent. That's what you want. Maybe around $1000 these days. Per my Swiss cheese memory cells, the model was a Walker VLF-80D, and it covered power frequency to maybe 50 kHz or thereabouts. I believe it had an output you could feed to a spectrum analyzer so you could see the individual harmonics, in addition tot he meter giving total field intensify as a number. Ken Javor Phone: (256) 650-5261 > From: "Jayasinghe, Ryan" <[email protected]> > Date: Thu, 3 Feb 2011 13:11:54 -0800 > To: "'[email protected]'" <[email protected]> > Conversation: Gauss Meter recommendation > Subject: Gauss Meter recommendation > > Dear Group, > > I have been tasked with recommending a Gauss meter and welcome your comments > and experiences. > > This meter will be used to determine if a certain residence is receiving too > much EMF. > > There are power lines just outside and the residents have trouble sleeping, > they have other residences where sleep is not an issue. > > I have looked at some 3 axis models for around $300.00, ones with data logging > are more. > > Is frequency weighting an important feature? We are also open to renting. > > We have a hp spectrum analyzer/biconical antenna but that would be too > unwieldy. > > If portable or handheld spectrum analyzer would be the better tool, this maybe > an opportunity for me to purchase one. > > Any advice is appreciated. Models methods anecdotes... > > Regard, > > Ryan > > Ryan Jazz Jayasinghe Compliance Engineer x1198 > Canoga Perkins Direct:(818) 678-3898 > 20600 Prairie Street Company:(818) 718-6300 > Chatsworth, CA 91311-6008 e-mail: [email protected] > www.canoga.com FAX:(818) 678-3798 > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > <[email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://product-compliance.oc.ieee.org/ > Graphics (in well-used formats), large files, etc. can be posted to that URL. > > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher: <[email protected]> > David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
