Extech480823 Extremely Low Frequency Electromagnetic Field Meter

Review for: Extech 480823 EMF MeterOVERVIEW:-----------Measures EMF strength of low frequency (30Hz-300Hz in this case) portion of AC MAGNETIC FIELD (NOT AC electric field, too) from ONE AXIS (direction) in milligauss (mG) or microteslas (uT).Because cell phones and microwaves are in a much higher frequency range, this product does not measure EMF (RF) at those frequencies. You would want a separate meter for that.The Achilles Heal of this instrument is that the design is HIGHLY INACCURATE for LOWER EMF readings. The accuracy is not 4% of the displayed value (+ 3 digits) but rather THE ACCURACY IS % OF THE VALUE OF THE END OF THE MEASUREMENT RANGE (4%x200mG = +/-8mg (+ 3 digits). Since the vast majority of the consumer use of EMF checking is in the single and low teens mG, this is unfortunate.This will do fine for noting the EXISTENCE of stronger EMF at lower frequencies, but appears to be a highly inaccurate choice for MEASURING it.MAIN VALUE:------------- Measures EMF at 30Hz-300Hz low frequency range (Magnetic AC field only, not Electric AC Field), which covers most EMF generated by AC power in most homes/offices. 60Hz (U.S.) and much of the EMF generated by resulting harmonic frequencies .. 120Hz (2nd harmonic), 180Hz (3rd), 240Hz (4th), 300Hz (5th).CONS:------- HIGHLY INACCURATE for LOWER EMF readings .. a fixed +/- 8.3 milligauss (mG). Since most suggested defensive limits for extended exposure are 1mG-2mG or so, this greatly limits its utility. See paragraph above under "The Achilles Heal of this instrument.." for more detail.- Measures only AC magnetic field (mG/uT), NOT AC ELECTRIC FIELD (V/m,mW/cm2, etc.). Adding electric field measurement with decent accuracy would have added greatly to the cost.NOTES:-------- Like other meters anywhere near this price range, the company doesn't claim this unit will filter out <30Hz and >300MHz EMF as well as academic/professional units like the Enertech Emdex II filters out EMF from outside its measurement range.- This frequency range does not cover cell phones or cordless phone signals, microwave oven radiation, or other high frequencies often referred to as RF (radio frequency).SAMPLE EMF MEASUREMENTS:-----------------------------There is no definitive consensus nor clear epidemiological evidence yet as to how much milligauss (mG) for extended periods could be harmful (within reasonable home/office real world levels). However, there is a consensus from studies that staying under 1mG-4mG would be a good defensive strategy in case 20-40 years from now longer term studies (think smoking, etc.) start showing stronger causal relationships. Most folks who care about this aim for under 2mG, preferably under 1mG, especially where pacemakers can be involved.Here are some sample readings of LOW frequency AC MAGNETIC field EMF (Note: not electric field):(1) Alarm Clock3" 25mG6" 10mG1' 3mG1.5' 1.8mG2' 0.5mG(2) Microwave Oven #1 (Home)Towards decent seal:6" 10-30mG1' 4-25mG2' 1.5-5mGTowards questionable seal:6" 160mG1' 45mG2' 15mG(3) Microwave Oven #2 (Office)6" 50mG1' 20mG2' 3mG3' 1.2mG(4) CRT Television (20" Sony WEGA)Down the middle:6" 0.9mG1' 0.5mG2' 0.2mGCorners:6" 5.5mG1' 3mG2' 0.7mGSides/Edges in the middle vertically:6" 7mG1' 3.5mG2' 0.9mG(5) 2012 LED Television3" 0.6mG(6) Dehumidifier (Large 70pt. Frigidaire)Around most of it:1" 0.5mGOn one side we get:3" 4.3mG6" 1.4mG1' 0.6mG2' 0.3mG(7) High-End Modern Very Large Copy MachineNot much mG at all(8) Office Ceiling Fluorescent Bulbs6" 50mG1' 20mG2' 3mG3' 1mG(9) Uncovered CFL Bulb3" 3mG6" 0.5mG(10) Box Fan6" 6mG (from center motor only)1' 1mG(11) Standing child's fan6" 6mG1' 1.2mG18" 0.6mG(12) Washer (Clothes)Top:1" 15mG6" 0.5mG-1.5mGBottom - Usually:6" 0.9mG-1.5mGBottom - while Spinning:3" 35mG6" 22mG2' 4.5mG3' 1.9mG4' 1.3mG(13) Dryer (Clothes)Top:6" 0.5mGBottom:6" 1.5mG(14) DishwasherTop:6" 2mG1' 1.5mG2' 0.7mGBottom:6" 12mG1' 5mG2' 1.8mG(15) AutomobileMoving car:Head heightLap 2.2mGStopped car:Head height 0.5mGLap 1.4mGEMF METER SHOPPING GENERAL NOTES:--------------------------------------EMF FROM LOWER FREQUENCIES:At LOWER FREQUENCIES we can measure magnetic fields (in milligauss (mG) or microteslas (uT)), and higher end units also measure electric fields (V/m,W/cm2, etc.). Unlike higher frequencies where magnetic and electric fields are strongly coupled together, at lower frequencies you measure them separately.As noted elsewhere in the review, for biological exposure it is suggested to play defense and keep prolonged exposure from lower frequency Magnetic Fields to under 1-4 mG (preferably under 1-2 mG) but there is no definitive consensus as to the long term biological dangers, and where the safety lines are.Regarding Electric Fields of 50-60Hz (AC Power), there is some rough consensus out there to keep below 10-20 V/m and sleep at a spot below 5 V/m, though again opinions vary. 5 V/m was the recommendation in Germany and by the IRPA/INIRC for "private individuals", 10 V/m for "workers", with 25 V/m for "workers" for max. 2 hours. ACGIH recommend 1 V/m for those with pacemakers or other electrically sensitive implants.The fields in the lower frequency ranges are sometimes referred to as ELF (see chart below for usual acronym meanings of this sort), or even confusingly as EMF which is also often used to define such fields at most frequencies.EMF(RF) FROM HIGHER FREQUENCIES:At HIGH FREQUENCIES like those the high frequency meters measure, the magnetic and electric fields are coupled so strongly together that it is one field that is measured, usually in V/m or mW/cm2, etc.For microwave ovens (2.45 GHz) biological exposure is often recommended to not exceed 5 mW/cm2 (milliwatts per cm squared), however again opinions vary.Some school or hospital exposure limits for 300MHz-300GHz:- France, Italy 10 mW/cm2 in schools- Switzerland 9.5 mW/cm2 in schools, 4.25 mW/cm2 in hospitals- Belgium, Luxembourg 2.4 mW/cm2For RF Fields of 900MHz, exposure limit recommendations around the world appear to range from .001W/m2 to 4.5W/m2, the latter being in Germany and the ICNIRP recommendation in '98.For RF Fields of 1800MHz, exposure limit recommendations around the world appear to range from .001W/m2 to 9W/m2, the latter being in Germany and the ICNIRP recommendation in '98.The higher frequencies are often referred to as RF (radio frequency) frequencies (think cell phones, microwaves, etc.) and thus you'll see some meters with "RF" in the title or description.MAGNETIC VS. ELECTRIC FIELD MEASUREMENT:AC MAGNETIC FIELDS are much harder to shield than electric fields. On the other hand unperturbed AC ELECTRIC FIELDS are much harder to measure accurately/dependably than Magnetic fields. IEEE tries to help with IEEE 644-1994. The inexpensive models don't pretend to measure this as well as the Enertech Emdex II's of the world, however they are often much less expensive and there's your trade-off.Note that AC ELECTRIC FIELDS often remain as long as the the source is plugged in, whether it is turned on or off.So for biological concern, what do people care about, magnetic or electric fields? An engineer in the field that has been following this noted that in the 70's it was electric fields, in the late 70's and 80's it was magnetic fields, and now it's really both. Most inexpensive units are only good for detecting the PRESENCE of stronger fields (vs. measuring them well) and many only measure magnetic fields, and if they do measure electric fields it usually isn't accurate. If you need to measure accurately and/or measure both magnetic and electric fields, I try to help out in this review with some leads later on.GENERAL:Meters not designed for it avoid 0Hz since that is the natural ground DC static field and we usually want to ignore that for measurement. Also there is often comparatively little EMF produced 1Hz-40Hz (some European train systems do FYI - 16.7Hz). Thus meters often aren't missing much EMF in the low frequencies when we buy meters that don't cover below 30Hz-40Hz.The frequency range of 30Hz/40Hz to 300Hz usually covers much of low frequency EMF produced in a home or office. This includes the U.S. 60 Hz AC power frequency and 4 of the harmonic frequencies from that. Thus we usually aren't missing much EMF in the low frequencies when we buy meters that don't cover over a few hundred Hz or so. However, note that capping the upper end of the low frequencies in the low hundreds may fail to capture a good portion of CFL's EMF (compact fluorescent lights) if that is important to you.Note that measured values can become less trustworthy as you get very close to the source of an EMF field, so measuring practically next to the source is often questionable.Also note that pulsed EMF is usually not read accurately by EMF meters.Note that if you need to take high radar frequency field strength into account (think Traffic Control Radar, Aviation, Naval, Military) because say you live near an airport and are wondering .. you'll probably need a meter that reads in the 8.5GHz-9.5GHz range.Note: I can't imagine who might work so close to one, but keep CFL bulbs without specific UVB and UVC mitigation (think double-envelope eco bulbs, for example) more than 20cm/8" from people at the bare minimum. If you don't know the technology of your CFL bulb, might as well play defense.FREQUENCY USE LEGEND:-------------------------- Static Field = 0Hz- Some European electric rail = 16.7Hz- Amtrak electric wire driven trains in U.S. southern NE corridor = 25Hz- AC Power for home/business (much of Europe) = 50Hz- AC Power for home/business(U.S.) = 60Hz- U.S. AC Power natural harmonics = 120Hz, 180Hz, 240Hz, 300Hz, 360Hz.. up to 800Hz for most.- 2Hz-100KHz includes many energy saving lamps, switching-mode power supplies, electronic dimmers, and monitors.- Some specialty small/light/fast motors (some server rooms, aircraft, ships, some power tools, etc.) = 400Hz- RF Animal Identification = 125KHz(U.S.) and 134.2KHz(Intl) (penetrates mud, blood, water)- Dect 6.0 cordless phone (most secure, least conflict) = 1.9GHz- Other cordless phones = 900MHz, 2.45GHz, 5.8GHz- WiFi (802.11) = 2.45GHz or 5GHz- Bluetooth = 2.45GHz- Many radio control cars, planes, etc. = 2.45GHz- RFID (Radio Frequency Identification .. EZ-Pass, supply mgmt,etc.) = 135KHz, 13.56MHz (13.553-13.567), 433.92MHz, 2.45GHz (2.4-2.483), 5.8GHz (5.725-5.875). Also, though probably not used as much, 6.765MHz-6.795MHz, 7.4MHz-8.8MHz, 26.957MHz-27.283MHz, 868MHz-870MHz, 902MHz-928MHz.FREQUENCY ACRONYMS:------------------------3Hz-30Hz ULF30Hz-300Hz ELF300Hz-3kHz VF3kHz-30kHz VLF30kHz-300kHz LF300kHz-3MHz MF3MHz-30MHz HF30MHz-300MHz VHF300MHz-3GHz UHF3GHz-30GHz SHF30GHz-300GHz EHFHz = Hertz (1/sec frequency)kHz = Kilohertz (1000/s)MHz = Megahertz (1million/s)GHz = Gigahertz (1billion/sec)SOME ORGANIZATIONS REVIEWINGEMF/RF BIOLOGICAL EFFECTS:---------------------------------Here are some of the more scientific organizations with available EMF/RF research or overviews that might be of interest to you:ACGIH - American Conference of Governmental Industrial Hygienists.IRPA - International Radiation Protection AssociationSCENIHR - Scientific Committee on Emerging and Newly Identified Health Risks (European Union advisory group).INIRC - International Non-Ionizing Radiation CommitteeICNIRP - International Commission on Nonionizing Radiation ProtectionWHO - World Health Organization International EMF ProjectU.S. EMF RAPID Program - 6 year working group put together in the past by NIEHS, NIH, and DOE.NRC/NAS - National Research Council / National Academy of Sciences by way of National Academy PressCA Dept. of Health Services - CA EMF ProgramIEEE - Institute of Electrical and Electronics EngineersVDB - Association of German Building Biologists (Verband Deutscher Baubiologen)Further future related research discoveries are likely to involve, or at least be reported on, by one or more of these organizations as they have been involved in such research in the past (much of it you can find on the web).HOW TO GET 3D READINGS FROMFROM 3 XYZ AXES METER READINGS:------------------------------------While some tools take "3D" readings, to save money some folks buy meters that read 1 or 3 individual axes, not a composite "3D" reading.To make a "3D" reading out of the individual axes readings you are supposed to put each of the three axis meter readings into the equation "square root (x-squared + y-squared + z-squared)".However, here are some short-cut estimations for less demanding needs that some use:Measurement Value:......Corresponding Guesstimate1 High, 2 Low values....Use highest value2 High, 1 Low value.....Use highest value plus half of second highest3 similar values........Use 1.5x highest valueMEASURING SUGGESTIONS:--------------------------Consider/test:- Keeping unit over 1ft away from any conductive material like metals.- Putting unit on a non-conductive holder like dry wood or cardboard.- Reading meter from 5 feet away.- If measuring over a bed, measuring 2" above mattress to take pillow into account and lessen the measurement effect of the springs (if there are any, of course).SOME OTHER METERS:----------------------If looking for a high-end, accurate low frequency EMF meter, consider starting your research with these:(1) ENERTECH EMDEX IIMeasures AC Magnetic and AC Electric Fields in the 40Hz-800Hz range, 3-axis, 1-2% of value accuracy. Sold to power companies and universities in 50+ countries, this is a leading industry tool. It also has recording, event marking, and software capabilities consistent with the needs of consultants. It is also excellent at filtering out EMF outside 40Hz-800Hz and is unusually accurate in reading AC Electric Field. ($2,950 for base unit)(2) GIGAHERTZ SOLUTIONS metersMade in Germany, sold in North America through Safe Living Technologies, Gigahertz Solutions has a wide variety of accurate affordable models that cover many frequency ranges priced from under two hundred to over a thousand dollars. Here are some of them, all these listed have HIGH ACCURACY and measure both AC MAGNETIC and AC ELECTRIC fields:3030B 16Hz-2KHz ($175)This model is a value sweet spot for non-professionals, offering most of everything one is looking for in accurately low frequency magnetic and electric fields.ME3030B Electromagnetic Field Meter3830B 16Hz-100KHz ($270)This model extends the frequency range to include a range sometimes controversially referred to as dirty electricity. CFL bulbs, switching-mode power supplies, electronic dimmers, and monitors sometimes fall in this range, too.ME3830B - Standard Electromagnetic field meter for Low Frequency3840B 5Hz-100KHz ($400)The addition of frequency filters for source analysis is the important added feature here, not as much the extension at the lower range.ME3840B - Semi professional Electromagnetic field meter for Low Frequency3851A 5Hz-100KHz ($540)Before the NFA1000 the ME3851A/ME3951 were the models most used by professionalsME3851A/ME3951 models have data outputs[Not Amazon listed atm]3951A 5Hz-400KHz ($770)Before the NFA1000 the ME3851A/ME3951 were models most used by professionalsME3851A/ME3951 models have data outputsME3951A Professional Electromagnetic Field Meter Low Frequencies Gauss MeterNFA1000 3D 5Hz-1000Hz ($2400)3D AC Magnetic and AC Electric Field reading, a time saver for professionalsGigahertz Solution's competitor to the Enertech Emdex IIComes with data analysis softwareAccurate 3D readings of AC Electric fields is considered a tough task, hats off to the Gigahertz Solutions folks for upping the ante.Magnetic Electric Meters NFA 1000 EMF Analyzer-5kHz to 1,000,000 kHzSPECTRUM ANALYZERS. To measure EMF/RF field strengths AT DIFFERENT FREQUENCIES you will need a spectrum analyzer. Some consultants use these for higher-end analyses, however there is usually much more expense and skill involved clearly. Below is the maker of an affordable hand held spectrum analyzer solution you may wish to read up on..(3) Aaronia AG Spectran handheld spectrum analyzerI suggest reviewing their website for model options if considering these, there is a variety of models and bundles covering different frequency ranges, covering both AC Magnetic and AC Electric Fields. The U.S. Distributor is Kaltman Creations (Aaronia AG is in Germany).- Low Frequency Range Examples:Aaronia AG Spectran NF-1010E (10Hz-10KHz, Magnetic and Electric Fields, 5% accuracy)NF-1010E AARONIA Handheld Spectrum Analyzer (10Hz - 10KHz)Aaronia AG Spectran NF-3020 (10Hz-400KHz, Magnetic and Electric Fields 5% accuracy)NF-3020 AARONIA Handheld Spectrum Analyzer (10Hz - 400KHz)Aaronia AG Spectran NF-5030 (1Hz-1MHz, Magnetic and Electric Fields, 3% accuracy)[Couldn't find on Amazon](4) If you are considering spectrum analyzers and money isn't much of an issue you might consider reviewing Tektronix, HP, and Agilent offerings, too, perhaps others, just to know what's out there at the high-end if nothing else. Of course, for most folks this is way out of budget and often skill set.I hope this helps some folks serious about EMF/RF measuring get started.

Well, I guess most people use these for other things, or should I say entities?Extremely sensitive. Found high levels of EMF in two spots in my house. One spot was when I had a light switch on in the hall. Extremely high EMG that peaked at over "38" near the switch! The other spot was an unshielded lamp cord that peaked at "14". Gotta get those fixed one day. The remainder of the house read either "0" or ".1". Among the biggest "leak" culprits are AC adaptors, TV's and desktop computers.For the money, I think this is well worth the price. It's built pretty tough, and will fit in your pants pocket fairly tight. The only thing I don't like is that the EMF sensor is located on the display-side (front), of the unit. I don't know if this is typical of these types of meters though. Also (not important for my usage), the display is not illuminated (for those of you who go out at night in search of things that go 'bump" in the night!). Hey, it's a good reason to carry a flashlight with you!Happy EMF hunting.

Pros: The meter does what it's designed to do. Can't count how many times I've dropped this thing and it still works as good as the day I bought it. Pretty rugged casing. Big digital display. I like the little pop-out stand.Cons: Seems that it's a little susceptible to skewed readings if you're moving compared to some other meters that do the same thing. And as a paranormal investigator, I am often on the move while taking readings. Wish this thing had a faster sample rate, as it's only 1 update per second. No back-light is a downer.Overall, this was the first EMF meter I bought, and I still use it on all my paranormal investigations. It's a solid meter, just as the title states. The only downers are simply due to it being a basic, one-use meter. If you're in the need for an average priced EMF meter that's going to stand up to some abuse, I'd recommend this one. However, if you have a slightly larger budget, you might look into some other options with nicer features.

I was pleased to receive the Extech in very good condition with a good functioning battery. I have discovered how far away from the fuse box, in the bedroom I need to be to avoid the EMFs. Also discovered that the computer , at close range releases up to 1.91 u Tesla from its side. Also my small illuminated small electric clock releases considerable EMFs and it and the clock radio are put far away from sleeping area.Yes I am pleased to have it and puts my mind at rest to a greater degree.

I got this item when I was staring up my Paranormal Hobby. This worked so well the first night we bought a couple more...THe ease of use perfect in the field. Turn on select you scale and read the big display I just wish they had a light so I didn't need to keep turning on my flash light.I was so impressed with the durability of this I also got the Extech Thermal gun for my team.For the beginner Paranormal Investigator it's a no brainer for the price.

I bought this EMF meter under Express Shipping it took 2 days longer to arrive than expected. But that was Offset with the Wonderful product this is for me and my household. We as a family discovered amny important things which we did not know about the appliances around the house such as, Refrigerator has the maximum radiation of EMF and it comes to our toilet while bathing!! AmazingAlso that there were no paranormal activity in the house. Took this to the graveyard and detected 40+ mGauss readings disappearing suddenly.This is great for know how radiated your area is around the place you live or work. Long term radiation can lead to dreadful diseases this product leads you to that awekening. I even measured my Gems and Crystals which have 30hz+ radiation as well.I am completely satisfied with the results

Unit received is indeed solidly build and works as advertised, although being of a single axis type, i would not trust 100% its measurements. Although and saying that, I found many spots in my flat with really dangerously high magnetic fields, specially around SAT receivers, alarm clocks, power stabilizers (very high magnetic fields there), and even those small power bricks which comes with many devices nowadays like, laptops, iPod music players/chargers etc.The seller was first class and the item was dispatched in excellent condition, by registered mail (a nice touch).I would highly recommend this unit for small around the house electro magnetic field measurement, where it proved to be very useful indeed. For those who want a better detailed measurements, I would recommend finding a 3 axis unit instead.

Friends and relatives bought houses near electrical lines, or scouted houses near them to buy.Used this to measure electromagnetic fields near houses they interested in, very good. Just stand still or sit still in car when you measure.It does its work. For the price, pretty good.

Yep, it's a nice and robust device. I have managed to find an EMF source of more than 1 Gauss in my apartment-studio (in Luxembourg) next to my bed - the EMF sensor readings were more then the maximal value...) !!(...terrible, I guess)

Not in accord with some of the other oppinions. When compared with other more expensive devices the indications proved to be quite similar. In conclusion it seems a reasonable trustable device for its price.

Rien à signaler... c'est conforme, c'est pratique et c'est facile à prendre en main . Je recommande pour une utilisation dans le quotidien.