I don't know how BPL really works in detail but there are a few basic physical principles that apply regardless:
1) If the measurements of interest are really in the near field, especially in the induction field, then the only valid measurement is to use the same type "antenna" as the likely victim, and place it the same distance from the source as the victim will occupy. The idea of measuring a field intensity in the near field is worthless. What you are measuring is the noise potential delivered to a receiver connected to a representative victim "antenna" or more accurately, field probe. This is very close to the old idea of an "antenna-induced" limit, except that concept was based on open-circuiting the probe output, whereas here we are talking about power delivered into a 50 Ohm receiver front end. 2) The probe must look like the victim to be protected by the limit. If an electrically short whip is being used, you don't use a loop and try to correlate the two. And vice versa. And the whip or loop being used needs to be the same size as the likely victim - the probe delivers a potential that is proportional to the average field impinging over its physical aperture. Unless the field is close enough to a plane wave that over the physical dimension of the probe it is homogenous, you cannot correlate the output of two different size probes, even if they are both whips or both loops. Further, you cannot extrapolate the field intensity to another distance other than that measured unless you have a priori a complete understanding of the current distribution on the transmitting structure and are only using the probe to get an amplitude data point. Ken Javor From: "Iain Summers" <[email protected]> List-Post: [email protected] Date: Fri, 18 Mar 2005 12:33:53 -0000 To: "Georgerian, Richard" <[email protected]>, "IEEE emc-pstc" <[email protected]> Subject: Re: Broadband Communications over Power Lines I am doing a PhD in the UK on the radiated emissions from BPL. I am looking at the measurement techniques and the associated errors that arise from using what are effectively far field techniques brought into the near field. If anyone has any views on measuring large structures that are not an a qualified OATS and also in the near field I would be keen to hear them. I hope to publish a paper later this year covering such things as field attenuation with distance, using loops and monopoles, and the conversion of H to E using 377 Ohms as an assumed impedance. We will be and have measured at a range of trial sites in the UK, as well as Europe and across the pond. Iain ----- Original Message ----- From: Georgerian, Richard <mailto:[email protected]> To: IEEE emc-pstc <mailto:[email protected]> Sent: Thursday, March 17, 2005 10:27 PM Subject: Broadband Communications over Power Lines Greetings All, Is there any one in the group who would have interest in writing and presenting a safety related paper regarding BPL (Broadband Communications over Power Lines) for the up coming 2005 IEEE EMC Symposium? Some special sessions are being developed for BPL, but the majority of the papers will be on emissions and immunity. If interested, please contact me off-line and I can then you give more details. Best regards, Richard ===== Richard Georgerian Technical Committee 8 Product Safety (TC-8), Chair Senior Compliance Engineer Carrier Access Corporation 5395 Pearl Parkway Boulder, CO 80301 USA Tele: 303-218-5748 Fax: 303-218-5503 mailto:[email protected] ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
