Cortland, Interesting, which leads to the question:
How much RF energy does it take for cardboard to ignite in that frequency range? (assume dry cardboard in 30%RH @ 20C) Doug From: [email protected] [mailto:[email protected]]On Behalf Of Cortland Richmond Sent: Wednesday, December 07, 2005 10:53 AM To: ieee pstc list Subject: Re: Antenna fro RS testing from 100 MHz to 200 MHz Derek Walton wrote: >> CM051207.004 << That's because the entire message was an attachment and OZWin buries attachments in its mail directory under an esoteric name. Better to send short messages in the message body, I think. What it asks is: >>I'm looking for an antenna optumised for transmitting inside a shield room from 100 MHz to 200 MHz, does anyone have suggestions on what design I could use?<< Drawings illustrating military and DO-160 RS test setup for 200 mHz or below show a biconical dipole in front of the equipment under test. This was also the standard for EN RS tests below 200 MHz, and is IMO near ideal for the 100 - 200 MHz range. You might as an experiment build a bow-tie dipole; that is functionally quite similar and the only challenge building it might be the balun and impedance matching. Sleeve dipoles covering the 225 - 400 MHz UHF military aircraft band are detailed in Johnson and Jasik, and you could scale that design for ~100-200 MHz, though it is quite a bit more complex than a bow-tie. An LPDA is also a possibility and an experiment doesn't have to cost much; you can make one out of copper tape on a sheet of plastic, or even cardboard. Johnson and Jasik, the ARRL Antenna Book and a number of other sources explain LPDA design. Where field strength is the only parameter measured you don't need a calibrated radiator, only a reliable, efficient one, and the experiment, if built to professional standards (no one believes in cardboard!) could turn into a useful piece of gear. Cheers, Cortland Richmond ka5s - 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
