I second those antennas. We’ve used the ARA conical monopoles 1-18GHz with enough success.
Dennis Camell National Institute of Standards and Technology ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Price, Edward Sent: Thursday, December 04, 2008 6:58 AM To: [email protected] Subject: RE: High frequency Antennas for EM surveys ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Price, Andrew (SELEX GALILEO, UK) Sent: Wednesday, December 03, 2008 11:56 PM To: [email protected] Subject: High frequency Antennas for EM surveys Hi everyone I am looking for an Antenna 1GHz to 18GHz that can be used for em survey work. This antenna is required for measureing EM fields inside vehicles as well as outside. The standard double ridge horn has too much directivity. I have already identified an antenna to cover the frequency range 30MHz to 1GHz this is an active dipole by Credence Technologies. Can anybody advise??? Regards Andy Andrew P. Price Principle Hardware Engineer, EMC Specialist Andy: Fields inside a vehicle are going to be influenced considerably by reflections >from the many nearby surfaces. You might want to consider measuring power density and converting to a field strength. If you still want to use an antenna, then the very old Polarad CA-B comes to mind. This antenna was a vertically polarized discone, so it was omni in the horizontal axis. Antenna factor was about 40 dB from 1 GHz to 10 GHz, so I don't know if it degraded gracefully up to 18 GHz or what. Still, the design is valid, if you want to build your own discone. Essentially, a coax penetration of a 12" diameter ground plane, with the center conductor blended into a cone that extends maybe 6" to a 6" diameter. Build it solid and get a traceable calibration, and you're ready to go. It might be advisable to think about using a couple of stirrers to maximize you detection probabilities within the vehicle. Regards, Ed Price [email protected] <blocked::mailto:[email protected]> WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military & Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]>
