>-----Original Message----- >From: [email protected] [mailto:[email protected]] >Sent: Wednesday, March 24, 2004 2:58 PM >To: [email protected]; [email protected]; [email protected] >Subject: RE: Use of Wi-Fi in our EMC lab > > > >Gert, > >I don't think the cable normal mode termination, or VSWR, will make a >difference in this case. As stated by Don Brown the fault likely lies >with the connector at the R&S receiver. The ferrite beads reduce the >shield current thereby reducing the current through the R&S >connector-chassis path. Another method that can work is to >place two 1/4 >wavelength radial wires connected to the shield 1/4 wavelength from the >R&S receiver. The radials should extend at a right angle to >the cable. I >ran a simulation and the current at the R&S is reduced by 20 >dB. Another >method is to place a sleeve balun over the coax. It will be 27 >inches or >so in length. Connected to the shield 27 inches from the R&S and left >open at the R&S. Unless it has an air gap the dielectric >constant of the >outer dielectric cover on the coax will cause the optimum length to be >reduced. Probably some copper foil and careful trimming to resonance >would knock down the offending signal. Ferrites sound simpler but a >ferrite-free solution can fun to try and is good practice for when you >find yourself on a desert island without any ferrites. > > Dave Cuthbert > Micron Technology
I'm going to give that 1/4 wave radial method a try. I have a small amount of coupling, just about 6 dB or so above internal noise, from my monitor, that leaks into the RF input of my analyzer at 48 kHz. Thanks, Ed Ed Price [email protected] WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
