Starting with an rf potential indicated on an EMI receiver, using the stipulated mho/m antenna factor yields amps/meter.
Makes sense to me if the limit is in terms of amps per meter. Ken Javor Phone: (256) 650-5261 From: Ed Price <edpr...@cox.net> Reply-To: Ed Price <edpr...@cox.net> Date: Mon, 27 Feb 2017 14:34:44 -0800 To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Passive Loop Emissions [General Use] Ralph: I¹m afraid that your explanation didn¹t get through to me. When I think of an electric field, I think of two voltage levels separated by a distance, so Volts per meter seems very descriptive. For instance, two plates, one meter apart, with one plate at 5 Volts and the other plate at 15 Volts, yields a field strength of 10 Volts per meter. Going logarithmic is simply a convenience for thinking about widely differing voltage levels, so again, very straight forward. Of course, you have to set a reference foe the log scale, so Volts or microvolts are equally valid. OTOH, mho/cm for a field is pretty obscure to me. Who uses that metric, and how? Ed Price WB6WSN Chula Vista, CA USA It's about as obscure as using "dBuV/m" for field strength Ralph McDiarmid Product Compliance Engineering Solar Business Schneider Electric From: Ed Price [mailto:edpr...@cox.net <mailto:edpr...@cox.net> ] Sent: Monday, February 27, 2017 5:37 AM To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Passive Loop Emissions [General Use] Andrew: I thought that S/m was a unit of electrical conductivity, defined as 0.01 mho/cm. This seems like a useless unit for magnetic field strength. I did find one site: http://www.mdltechnologies.co.uk/wp-content/uploads/2012/05/6512-datasheet.p df <http://www.mdltechnologies.co.uk/wp-content/uploads/2012/05/6512-datasheet. pdf> which provides a side-by-side chart for "dBS/m" and Electric Field Strength in "dB/m". At 10 kHz, the antenna factor in db/m is about 86 dB, while the antenna factor in dBS/m is about 35 dB. This sounds like the old relationship of magnetic field strength, in dBuA/m, to electric field strength, in dBuV/m, of 51.5 dB. Ed Price WB6WSN Chula Vista, CA USA -----Original Message----- From: Price, Andrew (Leonardo, UK) [mailto:andrew.p.pr...@leonardocompany.com <mailto:andrew.p.pr...@leonardocompany.com> ] Sent: Monday, February 27, 2017 4:16 AM To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: [PSES] Passive Loop Emissions [General Use] Hi All I need some help in obtaining the correct result. The customer has requested an extended magnetic field emission test over the range 100kHz to 2MHz with a limit defined in dBpT. The antenna to be used is an EMCO 6512 which has it correction factors provided in dBS/m which the emission software used does not recognise. So is there a conversion factor that enables the right correction factor to be entered or is the conversion factor only used once a result is obtained?? 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