It looks like you've answered your own earlier question, Ken; yes, you CAN see a difference between a leaky coax and good coax. I don't know that you can rely on the usual clamp-on current probe up at 400 MHz, but the relative difference tells you a good deal. And at 400 Mhz you only need a few feet for most of the power in shield current -- where the leaks end up -- to radiate away. You may also have copper losses in the shield -- which is not designed to carry signal current, remember -- as well as radiation losses through it.
However, 20 dB more than very little is not necessarily a lot. You can measure how much is lost to radiation by repeating your original test, but this time with a small-diameter - as tight as practical - copper tube replacing the braid, making an almost perfect shield. The power lost thorough radiation will no longer be dumped to space, and you should see that as decreased loss end-to-end. Cortland ------------------------------------------- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.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://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
