Measure electrosmog emitted by laptops or computers - Page 1
Forum section: electronics / general

author: jancelot
author_rank: Regular Contributor
timestamp: October 30, 2016, 05:36:25 pm
content: I would like to measure the electrosmog emitted by a particular laptop or desktop case, but the emissions related to normal operation. Wifi, bluetooth and such disabled.I've seen that Retro-PC-Mania uses the TES 593 (10Mhz - 8GHz) to measure electrosmog in shopping malls, but I'm not sure it will fit my purposes.I'm sure most manufactures comply with RF requirements by different approval seal or laws, but I have my doubts the values are still high.What do you think?

author: joeqsmith
author_rank: Super Contributor
timestamp: October 30, 2016, 06:00:11 pm
content: May not be as simple/inexpensive as you think to run a test like this with any sort of accuracy. Maybe start by reading the standards and seeing what is required.

author: VK5RC
author_rank: Unknown
timestamp: October 30, 2016, 08:13:32 pm
content: Serious EMC testing can be very expensive and time consuming, the Radio society of great Britain has an EMC committee and publishes regularly in the magazine RadCom. I think the USA amateur radio society, the ARRL, also has a similar section.A lot of cheap smpsu are very noisy in terms of RF. As a result I can't hear anything in HF radio at my place due to them.

author: jancelot
author_rank: Regular Contributor
timestamp: November 03, 2016, 02:07:40 pm
content: Thank you a lot for providing information about legal organizations, but I'm looking more specifically for a practical approach. No very high costs involved. Also, online information is important since I'm not living on either the United kingdom or the U.S.My main interest is measuring equipment under $600 for example, which can provide numerical values for comparison.All things said, looks like the TES 593 (10Mhz - 8GHz) is the recommended approach for general electrosmog measurements. There is also other equipment able to measure frequencies from 20Hz to several kHz, but I think that's for other things.

author: jancelot
author_rank: Regular Contributor
timestamp: November 03, 2016, 06:07:18 pm
content: Video that is extremely helpful:Stores and information:EMF Safety StoreLess EMFEMF CenterShocking grounding installation:Scary case of ungrounded iMac:

author: helius
author_rank: Super Contributor
timestamp: November 03, 2016, 06:14:47 pm
content: Using a multimeter is a pretty piss-poor way to measure electric fields: the frequency range to which they are sensitive is generally limited to the SLF range (30 to 3000 Hz). If you are only measuring them for "feel-good" reasons like the fellow in those videos, OK...The idea that these fields have any effect on humans has been pretty much debunked. But EMI in the HF range is of particular concern to amateur radio users, and won't be shown using silly multimeter tests.

author: jancelot
author_rank: Regular Contributor
timestamp: November 03, 2016, 06:23:33 pm
content: Quote from: helius on November 03, 2016, 06:14:47 pmWhat range are you talking about? Because "HF" range depends who you ask to.

author: helius
author_rank: Super Contributor
timestamp: November 03, 2016, 06:29:07 pm
content: Quote from: jancelot on November 03, 2016, 06:23:33 pmhttps://en.wikipedia.org/wiki/High_frequency(3 to 30 MHz, including most of the shortwave band). Radio also uses other bands, of course. For some purposes, it is undesirable to have EMI/RFI over a wide swath of the spectrum:

author: HighVoltage
author_rank: Super Contributor
timestamp: November 03, 2016, 06:30:22 pm
content: You could use a HFE35C Gigahertz Solutions RF-Analyser kit.They work pretty well to detect all kinds of electrical noise.https://www.gigahertz-solutions.de/en/emf-meters/high-frequency/meters/383/hfe35c?c=137

author: chris_leyson
author_rank: Super Contributor
timestamp: November 03, 2016, 07:41:00 pm
content: As for measuring EMF from your computer, EMF is electromotive force and strictly speaking it should RFI but there you go. I've always found common mode interference to be a big problem when trying to use software defined receivers or for that matter anything that is sensitive and wide band. Laptop power supplies are usually the culprit but sometimes the laptop itself can generate common mode noise on USB ports. I've found desktop computers are usually quieter.

author: jancelot
author_rank: Regular Contributor
timestamp: December 28, 2016, 07:55:55 pm
content: Quote from: HighVoltage on November 03, 2016, 06:30:22 pmIt looks great quality but it's missing the newer 5GHz band for WiFi for consumer electronics and the also the 5.9 GHz (802.11p) for vehicular communication systems. I can see that there are more expensive kits from Gigahertz Solutions like theMK70-3D PLUS 2.2

author: jancelot
author_rank: Regular Contributor
timestamp: December 28, 2016, 07:57:16 pm
content: Here are some instruments that I've found:*AlphaLab Trifield 100XE meter: measures all three types of electromagnetic field: AC magnetic field, AC electric field, and radio (including microwaves). The magnetic and electric detectors are 3-axis*TES 593meter: to measure electrosmog 10Mhz - 8GHz. Sensor type is electric field, isotropic, 3-dimensional.*magnetic sciences MC162: 2 kHz to 1 MHz AC magnetic field sensor, with BNC connector.*magnetic sciences 6GHz EMI probes: wideband single-axis probes allow low-cost measurement of magnetic and electric field strength, locating sources of electromagnetic interference (EMI) and radio frequency interference (RFI), microwave emissions, electromagnetic compatibility and EMC / EMI / RFI testing, and troubleshooting RF circuits.*AlphaLab UHS2: AC magnetic field meter, 13 Hz to 75 kHz, true 3-axis magnitude.*Gigahertz Solutions RF-ANALYSER KIT HFE35C: EMF meter 27 MHz - above 2.7 GHz.*EMFields AM-10 acoustimeter: microwave detector ranging 200 MHz - 8GHz. Has visual scales, LCD screen and speaker.*KEYSIGHT FIELDFOX and HSA: handheld spectrum analyzers, ranging from 5kHz to 50 GHz.*EMDEX Lite Magnetic Field Meter: Versatile Personal Magnetic Field Measurement System. 0.1 - 700 mG(0.01 to 70 ?T). 40 - 1,000 Hz. True RMS.

author: MisterDiodes
author_rank: Frequent Contributor
timestamp: December 30, 2016, 03:50:05 am
content: Quote from: jancelot on November 03, 2016, 06:07:18 pmGood grief - Not only is that guy in the video overloaded his outlets (depending on what's running) but with that black sleeving he made absolutely sure those cords will have a pretty high thermal resistance to the rest of the world. "Let me see how hot I can get these power cords!"He should be less concerned about EMF and more more worried about a fire insurance inspection....

author: jancelot
author_rank: Regular Contributor
timestamp: January 12, 2017, 09:38:21 pm
content: Quote from: HighVoltage on November 03, 2016, 06:30:22 pmGigahertz Solutions RF-Analyser are single axis? It's not specified on the website.

author: HighVoltage
author_rank: Super Contributor
timestamp: January 13, 2017, 06:03:59 pm
content: Quote from: jancelot on January 12, 2017, 09:38:21 pmGood question, I do not know but I would suspect it to be a single axis analyzer`

author: HighVoltage
author_rank: Super Contributor
timestamp: January 13, 2017, 06:05:51 pm
content: Quote from: jancelot on December 28, 2016, 07:55:55 pmThey have one version that goes to 6 GHz and another one that goes to 10 GHzhttps://www.gigahertz-solutions.de/de/messtechnik/

author: jancelot
author_rank: Regular Contributor
timestamp: January 13, 2017, 10:09:57 pm
content: Quote from: HighVoltage on January 13, 2017, 06:03:59 pmOk I've found that the HFE35C can measure from 27 MHz to 6 GHz, but the actual range depends on the antenna used:- The LogPer aerial supplied with the meter covers a frequency range of approx. 800 MHz to 2700 MHz. That is the logarithmic-periodic antenna (or aerial) and is exceptionally directional.- For a quantitative measurement of frequencies below 800 MHz with the HF59B, Gigahertz Solutions provides the active, horizontally isotropic ultra broadband antenna UBB27_G3 responding to frequencies from 27 MHz right up to more than 3.3 GHz.Source:https://www.gigahertz-solutions.de/media/pdf/g0/fa/cb/530-054_Manual_HF58B-HF58Br-HF59B_rev.6-0_EN.pdfhttps://www.gigahertz-solutions.de/en/emf-meters/high-frequency/meters/338/hf59b?number=530-054Quote from: HighVoltage on January 13, 2017, 06:05:51 pmi see. Actually some meters can measure more bandwidth if you use additional antennas than the ones included by default. In that case you want to buy kits, like the ones mentioned in that graph.https://www.gigahertz-solutions.de/en/cat/index/sCategory/137

author: jancelot
author_rank: Regular Contributor
timestamp: January 21, 2017, 08:35:45 pm
content: Quote from: helius on November 03, 2016, 06:14:47 pmYou are right. My Brymen BM257S has an AC voltage range of 50 to 400 Hz.The Brymen 869S has a range from 20 Hz to 100 kHz which is pretty good, but the accuracy varies depending on frequency and voltage range.The Fluke 87 V has an AC voltage range of 20 kHz with low pass filter; 3 db @ 1 kHz

author: jancelot
author_rank: Regular Contributor
timestamp: January 21, 2017, 09:12:55 pm
content: Gigahertz Solutions EMF meters:For the low frequencies, we measure electric fields and magnetic fields separately.TheME3030Bis the entry level M&E meter, costs about €150, range 16 Hz - 2 KHz (compensated, better than -2 dB), electric field strength from 1 to 1999 V/m (against ground potential), magnetic flux density from 1 to 1999 nT, acoustic signal. It's single-axis like most of the low frequency metersTheNFA1000is the top of the line for the low frequency meters. The frequency range is 5 Hz to 1000 KHz (compensated, +/- 2 dB), with 3D sensors for both electric field strength and magnetic flux density (3-axis). Cost is €1934.For the high frequency, we measure the electromagnetic radiation and ideally on the far field. Depending on the meter, there are two available antennas: one is the logarithmic periodic (highly directional) and the other is the isotropic. Either antenna has a different frequency range. Additional accessories and filters are available.The entry level meter is theHF32D, which costs about €250. Has a range of 800 MHz - 2.7 GHz, with a display of 1 µW/m² up to 1999 µW/m²The top of the line are theHF59B(27MHz - 2500MHz, €1166) and theHFW59D(2.4GHz - 10GHz, €1166).There are alsokitsavailable. The most complete kit is theELECTROSMOG MEASURING KIT "PROFI PLUS" MK70-3D PLUS 2.2, costs €5980.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 21, 2017, 09:38:27 pm
content: With those instruments labeled to measure electro-smog one has to be careful. It like a red hearing to have the bull-shit alert button ready.If they use arguments like negative health effects of electro-smog, I would not take the rest too serious.To get anything useful for EMI measurements you need frequency specific data and thus more than just a single number reading. Usually results are in dB, not just linear numbers as there is quite a large power range.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 21, 2017, 10:49:37 pm
content: Quote from: jancelot on October 30, 2016, 05:36:25 pm"Duh" solution:1. Inspect the label on the equipment.2. Find the FCC ID.3. Enter the FCC ID into the FCC database search.4. Read the registered measurements.Tim

author: jancelot
author_rank: Regular Contributor
timestamp: January 22, 2017, 03:34:15 pm
content: Quote from: Kleinstein on January 21, 2017, 09:38:27 pmSerious manufacturers never say that electric/magnetic fields or electromagnetic radiation is good or bad. They just release products to measure things and provide specifications. But I do not agree that certain levels are not dangerous.About frequency data, you mean representing the values for electric and magnetic fields in the frequency domain (using Fast Fourier Transform)? What hardware would that require?Some information I've found:-Propagation of ELF Radiation from RS-LC System and Red Sprites in Earth- Ionosphere Waveguide (ResearchGate)-Propagation of ELF Radiation from RS-LC System and Red Sprites in Earth- Ionosphere Waveguide (pdf)

author: Kleinstein
author_rank: Super Contributor
timestamp: January 22, 2017, 04:36:06 pm
content: The normal, more accurate way of looking at electromagnetic emissions is using a spectrum analyzer. Modern version might use a kind of FFT for some of this, classical ones are more like a scanning receiver, measuring a small frequency band at a time. With a limited dynamic (and often frequency) range a modern DSO with FFT function could be used.One usually also needs a reasonably shielded and absorbing room and well calibrated antenna.

author: jancelot
author_rank: Regular Contributor
timestamp: January 29, 2017, 06:20:10 pm
content: Quote from: Kleinstein on January 22, 2017, 04:36:06 pmCan you tell us a specific set of hardware? Digital Storage Oscilloscopes and other electronic equipment can generate their own electric and magnetic fields and interfere with the measurements, specially if you get the signal from an antenna instead of coaxial shielded cable. The Keysight Handheld Spectrum Analyzers are promoted as very good shielded (MINUTE 3:39):

author: jancelot
author_rank: Regular Contributor
timestamp: January 29, 2017, 06:49:54 pm
content: AARONIA AG also sells several meters, accessories and shielding materials, for example the Spectran HF-6060 V4 (10MHz - 6GHz):http://www.aaronia-shop.com/products/spectrum-analyzer/handheld/rf-spectrum-analyzer-spectran-hf-6060-v4

author: acbern
author_rank: Frequent Contributor
timestamp: January 29, 2017, 08:03:27 pm
content: Correctly measuring EMI is very complex. Not only do you need the correct spectrum analyzer (special versions are available, called e.g. EMI analyzer; they do measurements in accordance with EMI specific standards). You also need the proper environment and a calibrated set of antennas and an EMI chamber or a free area, with metal floor (very simplisticly speaking; detailled descriptions can be found on the net), or a TEM cell for smaller items. For most hobbyists, the effort goes beyond whats realistically doable.Overall, measuring electrosmog from a device like a computer, which was certified to CE/FCC anyway, with most of the meters described above, is just not doable correctly. At best, you can get a qualitative overview, comparing e.g. two computers. That is not necessarily very meaningfull. You can have two equal numbers, but one may still be not compliant (having a strong spike at a specific frequency, while the other has the energy broadly distributed). So the bad news is, correctly measuring the EMI of a computer (which is a low level emitter), is complex and expensive.In theory, if you find a cheap EMI antenna somewhere (i have never seen one, most are 2k up...), you could buy a 8590 spectrum analyzer (going up to 1.5GHz as a cheap solution, you get that below 1k. Not a quasi-peak analyzer, but will do. Move to your backjard which is located somewhere in an area with no EMI emitters around (industry facilities, radio stations...), do a scan without DUT, and do one with the DUT, and compare data. A metal mesh on the ground would be needed. All this is still far away from being standards-compliant, but is not too bad either. Dimensions are important (mesh size...., see information available on the internet). If properly set up, and with a good antenna in a suitable area, this could even be used as a setup for internal precompliance-testing, prior to doing an EMI certification.

author: jancelot
author_rank: Regular Contributor
timestamp: February 12, 2017, 08:38:45 am
content: A little update on the TES-593: use some accessory to keep it separated from your hand and body, since static electricity from a living organism can interfere with the measurements and increase the measured value. I don't know if it happens with Gigahertz Solutions or Aaronia hardware, but certainly does with the TES-593. It has a thread in the back to put there camera mounts or selfie sticks.

author: tooki
author_rank: Super Contributor
timestamp: April 02, 2017, 10:09:46 am
content: Quote from: MisterDiodes on December 30, 2016, 03:50:05 amOh, it gets better: He's using the multimeter with the red probe on the V input and the black probe on the 10A input! Someone pointed this out on the youtube comments, this was his reply: "I don't know the difference between using the com vs the 10a plug but they both read the same voltage anyway. The 10a plug has always worked for me but you're probably right. ?"So what is he actually measuring, then??

author: helius
author_rank: Super Contributor
timestamp: April 02, 2017, 10:35:08 am
content: The amps jack is connected to the common jack by the current shunt. Misusing the meter that way has the effect of reducing the readings according to the voltage divider formed by the two impedances; since the shunt is very low impedance compared with the V input this has a small impact.

author: Howardlong
author_rank: Super Contributor
timestamp: April 02, 2017, 11:23:41 am
content: This is the seminal work on the subjecthttp://web.archive.org/web/20130307180428/http://berkeley.intel-research.net/arahimi/helmet/

author: tooki
author_rank: Super Contributor
timestamp: April 03, 2017, 09:26:06 am
content: Quote from: helius on April 02, 2017, 10:35:08 amOh, duh. I know this. Serves me right for posting right after getting up in the morning, before my brain is awake...

author: jeroen79
author_rank: Frequent Contributor
timestamp: April 04, 2017, 11:46:44 am
content: Quote from: helius on April 02, 2017, 10:35:08 amUnless he converted the fuse to an extremely high impedance on an earlier occasion.