I read in !emc-pstc that Ken Javor <[email protected]> wrote (in <bb2f7186.2be2%[email protected]>) about 'cable maximization - do you or don't you??' on Mon, 7 Jul 2003:
>I don't think it is at all complicated, at least in principle. Maybe a >devil will emerge out of some details I am missing... It's a point worth discussing. > >I don't see how an end-driven wire can radiate more efficiently than a tuned >half-wave dipole. That model can be used to convert from field intensity at >X meters to peak current on the cable. Agreed that it can't be more efficient, but it can be less efficient to a nearly unlimited extent, so making that assumption can be very pessimistic indeed. > >For the case of multiple cables one could make various assumptions about the >additive effect of emissions at X meters: > >A worst case assumption is that the same spectrum could appear on each cable >and add in phase at the measurement point. This would require subtracting >from the previously determined single cable current limit the factor: > >20*log (number of cables). > >I think this is unreasonable, that the summing would be of random phase and >the factor to be subtracted from the single cable current limit ought to be > >10*log (number of cables). Agreed, as a first approximation. > >I am not trying to say that this approach is precisely correct and should be >implemented as is. I do think it would be interesting to make some cable >measurements using an absorbing clamp and compare to the corresponding OATS >profile and draw some conclusions. Yes, I think that is justified, now that you have raised the subject. Unfortunately, many such proposals are never investigated because no-one has the time, even if the costs can be handled. I think we all look forward to your report of the first results. (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
