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 which provides a side-by-side

Re: [PSES] Passive Loop Emissions [General Use]

Quite likely, but condensing units like that is very confusing. I remember from a long time ago, someone complaining about it and citing the reference pressure sensitivity of a piezo-electric element, which is (volts/m)/(newtons/ square metre). The American spec writer had condensed that to

[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

Re: [PSES] Passive Loop Emissions [General Use]

I think you have to ask EMCO, because that horrible dBS/m ( S = siemens) is mathematically unsound (don't ask) and is dB (amps/volts)/m, whereas picotesla only involves current, distance and the permeability of space, not voltage. This does assume that everyone is using the correct units and the

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

Agreed Ken. In this case the e-field conversion is irrelevant, and the specified antenna factor is what it is. From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Monday, February 27, 2017 11:11 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] CORRECTION (wrong page) Passive

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

MANY years ago when I ran the Amador lab in Colorado, we had a well-known RFID customer whose tags read at 150 kHz. Measurement distance for the FCC limit was 300 meters. It just happened that the far corner of our 8-acre property was very close to 300 meters as measured by my mountain bike's

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

If we go all the way back to the OP: > 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

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

On 2/27/2017 7:53 PM, Brent DeWitt wrote: I think Ken's rational makes sense to me, since the 51.5 is derived from 20*log(377). Sure, but now we're back to how close we are -- wavelengths -- to the emitter. 20*log(??) Low frequencies can be tricky, and I once had to double-check a test

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

It's valid in the absence of a magnetic material (relative permeability = 1). The 51.5 dB factor is based on the far field. Ken Javor Phone: (256) 650-5261 > From: John Woodgate > Reply-To: John Woodgate > Date: Mon, 27 Feb 2017 18:07:27 -

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

The phase angle between the electric and magnetic fields appears nowhere in the math. Electric field and 51.5 dB aren't even mentioned, nor 2.653 m$ (the fee for entering an infinitely wide-open door!). This purely a magnetic field relationship, B = µ_oH. With best wishes DESIGN IT IN! OOO –

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

On 2/27/2017 7:15 AM, Price, Andrew (Leonardo, UK) wrote: 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

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

The difference between dB(pT) and dB(µA/m) is 2 dB. dB(pT) -2 = dB(µA/m) -Original Message- From: Cortland Richmond [mailto:k...@earthlink.net] Sent: 27 February 2017 16:45 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

Re: [PSES] Passive Loop Emissions [General Use]

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] Sent: Monday, February 27, 2017 5:37 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Passive Loop Emissions

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

On 2/27/2017 12:23 PM, John Macaulay wrote: The difference between dB(pT) and dB(µA/m) is 2 dB. dB(pT) -2 = dB(µA/m) This is true only in the Far Field. - This message is from the IEEE Product Safety Engineering Society

Re: [PSES] Passive Loop Emissions [General Use]

On 2/27/2017 7:15 AM, Price, Andrew (Leonardo, UK) wrote: ... 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

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

I doubt that, because it's valid at audio frequencies, which undoubtedly means 'near field'. With best wishes DESIGN IT IN! OOO – Own Opinions Only www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England Sylvae in aeternum manent. -Original Message- From: Cortland Richmond

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

On 2/27/2017 12:23 PM, John McAuley wrote: The difference between dB(pT) and dB(µA/m) is 2 dB. dB(pT) -2 = dB(µA/m) His customer wants dB s/m, which is not printable with the TE software. From the EMCO manual: / /Cortland Richmond/ / . -

Re: [PSES] Passive Loop Emissions [General Use]

Ralph: I'm afraid that your explanation didn't 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

Re: [PSES] Passive Loop Emissions [General Use]

On Mon, 27 Feb 2017 12:15:43 +, "Price, Andrew (Leonardo, UK)" wrote: > 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

Re: [PSES] Passive Loop Emissions [General Use]

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 Reply-To: Ed Price Date:

Re: [PSES] Passive Loop Emissions [General Use]

Oops ­ sorry. What Tom Sato said. Ken Javor Phone: (256) 650-5261 From: Ken Javor Date: Mon, 27 Feb 2017 16:57:51 -0600 To: Conversation: [PSES] Passive Loop Emissions [General Use] Subject: Re: [PSES] Passive Loop Emissions [General

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

Accuracy within 1%, if measured outside the source loop by 3X, which is like 'far field' --- ken.ja...@emccompliance.com wrote: From: Ken Javor To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions

Re: [PSES] Passive Loop Emissions [General Use]

S/m does actually make sense (to me) as the antenna factor units for getting magnetic field strength. Since the input to our SA or receiver measures voltage, we get back to current by multiplying the voltage times the conductivity, or 1 over the impedance. That doesn't directly get you to

Re: [PSES] CORRECTION (wrong page) Passive Loop Emissions [General Use]

I think Ken's rational makes sense to me, since the 51.5 is derived from 20*log(377). Brent DeWitt, AB1LF Milford, MA -Original Message- From: Macy [mailto:m...@basicisp.net] Sent: Monday, February 27, 2017 2:54 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] CORRECTION