Derek, In this frequency range the combination of the low limit and the 40 or 50 dB coupling factor from the directional coupler is killing your sensitivity. I would suggest that in this frequency range a directional coupler is totally unnecessary, you can use a coaxial "tee" and connect an ordinary 1 MOhm input oscilloscope off the tee.
That should work for all BCI-type limits - note the following worst case example. A 1 V/m BCI limit at 10 kHz would be 23.5 dBuA. Driving that much current into a 50 Ohm calibration fixture would mean 23.5 dBuA + 34 dB Ohm = 57.5 dBuV. But at this low frequency your injection clamp insertion loss is around 30 dB (ubiquitous 95236-1 clamp), which means you would be putting 57.5 dBuV + 30 dB = 87.5 dBuV into your clamp, around 24 mVrms, 67 mVp-p. Easy to see on your scope. Ken Javor From: "Derek Walton" <lfresea...@aol.com> Organization: L F Research List-Post: emc-pstc@listserv.ieee.org Date: Sun, 5 Sep 2004 15:14:18 -0500 To: emc-p...@ieee.org Subject: Power Meter to read down to 10 kHz Hi Folks, I'm trying to improve my Conducted immunity test method when testing from 10 kHz to around 200 kHz. The signal from the diredctional coupler is quite small, around -20dBm, and my current power meter sensor is on the limits of it's range. Can anyone suggest a power sensor for use with the HP 437B ideally, that can measure down to -30 dBm and at least 10 dBm, with a freq range of 10 kHz to 400 MHz? If no such sensor exists ( and I've not found one... ), can anyone suggest a power meter/sensor combination. I only need a single channel, but two channels would be OK too. Thanks, -- Derek N. Walton L F Research Poplar Grove, IL 61065, USA ----------- ---------------------------------------------------- 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 emc-p...@ieee.org 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org 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 emc-p...@ieee.org 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc