These things all work the same way. My guess is that the cheaper units¹ calibration is not as accurate. The really cheap units are doubtless not individually calibrated the kind you find on eBay for a few bucks.
Ken Javor Phone: (256) 650-5261 From: Manny Barron <[email protected]> Reply-To: <[email protected]> Date: Fri, 28 Sep 2018 12:16:11 -0700 To: 'Ken Javor' <[email protected]>, <[email protected]> Subject: RE: [PSES] Portable EMI and Magnetic field meter for site evaluations During this survey I was curious about how accurate the portable sensor was. So I took it into our 5m radiated immunity semi-anechoic chamber and placed it next to an E-Field probe used for MIL-STD-461E RS103 testing and turned on the radiating system to check a few frequencies and field levels. I don't remember the details but the results showed good comparison at some frequencies and significant differences at other frequencies. Now I'm wondering if there are any published papers or studies about this that provide more insight. Manny Barron EMC Engineer From: Ken Javor [mailto:[email protected]] Sent: Friday, September 28, 2018 11:56 AM To: [email protected] Subject: Re: [PSES] Portable EMI and Magnetic field meter for site evaluations Given that the human exposure limits are frequency dependent, and the typical handheld meter is a broadband device, unless the handheld meter reading is either at or under the lowest human exposure limit, or at or above the highest limit, you don¹t know what to do with the output of a broadband device showing a problematic reading. The human exposure limits (per my fallible memory) are all way in excess of anything like 3 V/m. Ken Javor Phone: (256) 650-5261 From: Manny Barron <[email protected]> Reply-To: <[email protected]> Date: Fri, 28 Sep 2018 11:40:50 -0700 To: <[email protected]> Subject: Re: [PSES] Portable EMI and Magnetic field meter for site evaluations Hi Dan, Back in 2010 while employed at a military defense company I had to take some measurements for the very same purpose. I used a handheld portable unit manufactured by Narda: https://www.narda-sts.com/en/. Don't remember the exact model but it worked fairly well, it was handheld, battery powered, and portable. Had to take some readings of building interior and exterior areas (plus on the roof) that had a ground level log-periodic transmitting antenna pointed skyward about 20 feet from the building (all FCC permitted of course). Used the Maximum Permissible Exposure (MPE) limits in IEEE Std C95.1 as a guide and ended up having to install a small keep out fence around the transmitting antenna (don't remember the keep out zone diameter). By the way IEEE Std C95.1 has MPE limits as a function of frequency and some limits were higher than what I would expect (e.g., much higher than 3 V/m in certain frequency ranges, don't remember details). It was an interesting project. Hope this is helpful. Manny Barron EMC Engineer From: Dan Roman [mailto:[email protected]] Sent: Friday, September 28, 2018 8:39 AM To: [email protected] Subject: [PSES] Portable EMI and Magnetic field meter for site evaluations Hello List, Can anyone suggest a piece of test equipment that is battery powered that could be used in conducting a survey of data centers and factory floors to assess for electric and magnetic fields? Would be interested in looking at DC to a few GHz, not for meeting regulatory limits, but rather for grossly high levels that could affect persons who have implants such as pacemakers or artificial joints. So I guess there are regulatory limits that can be used, which would be the immunity levels that these devices are exposed to during their qualification. I know there are test labs that offer this kind of service. Anybody use one and know what type of equipment they brought in with them? Thanks in advance. Dan - ---------------------------------------------------------------- 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://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.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://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.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://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.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://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
