EMI Troubleshooting Kit
is a series of articles on the Test & Measurement website
that are very much worth reading if your job or hobby involves hunting
RF/EMI leakage into or out of a PCB or enclosure. Author
Wyatt has an impressive bag of tricks you can use. One slick trick
used by his colleague
Doug Smith involves
a literal bag with a few coins in it. Shaking said bag-o-coins generates
EMI with edges in the 100 ps realm. I know from much experience
about the electrical noise caused by metal-to-metal contact from the
days of 27 and 72 MHz radio control systems in model airplanes.
Throttle control arms on the carburetors used to be made of metal, and
using a metal pushrod for connection would almost guarantee jittering
servos from EMI interference. Meshing metal gears on early R/C helicopters
was a nightmare. But I digress. Another nifty trick used by Mr. Wyatt
is to use an igniter from a patio gas grill to generate wideband EMI.
He has an easy-to-make spark gap tool as well. Take a few minutes to
scan through some of the info; you'll be glad you did if for no other
reason than the "well, huh!" factor.
Posted March 2013