It is indeed Fischer Custom Communications at: http://www.fischercc.com/
They do have these coupling clamps. The founder, Joe Fischer, was friends or colleagues with Mr. Balint Szentkuti, who wrote several papers back in the 1980s about replacing radiated OATS measurements with common mode cable current measurements. The point about these clamps is that they are a combination current probe and stack of ferrite absorbers which are supposed to absorb standing waves and make the measurement more repeatable. However the stack of ferrites doesn't really kick in efficiently until you get to 30 MHz, they will not perform that absorbing function well in the BPL frequency range, given my limited understanding that it is HF, below 30 MHz. So if I am correct there, an ordinary rf current probe will work as well, and the (simulated) transmission line ought to be electrically short and matched, which will take care of the vswr problem. > From: [email protected] > Date: Tue, 8 Aug 2006 10:20:49 -0400 (EDT) > To: [email protected] > Cc: "John Woodgate" <[email protected]>, [email protected] > Subject: Re: Near field/Far field what is D. > > I can get down off of the wall now...I remembered the company name as > Fischer Custom Communication. (although I'm a little unsure if it's > "Fisher" or "Fischer") > > Chris > > >> John and Ken, >> >> Isn't this one of the main reasons that it's better to measure the >> emissions from a line with a coupling clamp at these frequencies (1 to 30 >> MHZ).??? >> >> There is a company that makes coupling clamps...and their name escapes me >> right now...About 10 years ago...when I was a wet behind the ears EMC >> neophyte...I remember reading some papers that they had written regarding >> the measurements of common mode cable currents and surface currents on >> chassis. >> >> In their papers, they stated that it was much more reliable and repeatable >> to use a clamp to measure the common mode current on a cable at 5Mhz as >> opposed to trying to measure the field radiated by that common mode >> current with an antenna. >> >> I believe that the coupling clamp method circumvented all of this >> near-field vs far-field determination. >> >> I wish I could remember the name of that company...it's driving me up a >> wall...all I can remember is Com-Power...or maybe Fischer??? >> >> Best regards, >> >> Chris Maxwell >> >> >>> In message <c0fd3eda.411bd%[email protected]>, dated Mon, 7 >>> Aug 2006, Ken Javor <[email protected]> writes >>> >>>> Now you could certainly idealize the transmission line for the >>>> purposes of a standard test, and you would need to, but if you do that, >>>> why not specify and measure the BPL current on that matched >>>> transmission line? >>> >>> Would you please clarify what you mean by 'transmission line' in this >>> context? Is it the transmission line between the BPL sender and the >>> mains network? >>> >>> I ask because I am involved in a similar issue; measuring the emissions >>> form audio-frequency induction loops fed by Class D amplifiers. At >>> present, measuring the current in one conductor of the cable between the >>> amplifier and the loop is believed to be the first possibility to be >>> investigated. >>> -- >>> OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk >>> 2006 is YMMVI- Your mileage may vary immensely. >>> >>> John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK >>> >>> - >>> ---------------------------------------------------------------- >>> 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/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: >>> >>> Jim Bacher: [email protected] >>> David Heald: [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/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: >> >> Jim Bacher: [email protected] >> David Heald: [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/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: > > Jim Bacher: [email protected] > David Heald: [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. 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