I can't speak about using hybrid antennas for NSA volumetric site attenuation measurements. However, depending on the amount of work you perform, you may consider buying two antennas anyway, since it is good to have a backup in case one is damaged or has to go out for calibration. I've used both for normal measurements. At one facility where I worked, they had two masts. One had a log-periodic and the other had a biconical. The automation software switched between the two and combined everything onto one plot. They also had two sets of antennas as well. Bob Richards, NCT.
Grace Lin <[email protected]> wrote: Dear Members, Does anyone have a successful experience in volumetric site attenuation (per ANSI C63.4, etc.) by using a pair of bilog hybrid antennas (30MHz to 2 or 3 GHz)? A VIP from VCCI told me that I would be challenged by using a pair of bilog hybrid antennas to perform volumetric site attenuation. For daily radiated emission measurement, bilog antenna are popular, especially using automation software for initial scan. For a manufacturer, it is hard to justify a pair of biconical (30MHz-300MHz) and log periodic (300MHz-1GHz) antennas just for site attenuation measurement, used once every three years (per FCC and Industry Canada). I did some research. There is a paper to address the measurement uncertainty of the bilog antennas, titled: "Understanding the measurement uncertainties of the bicon/log hybrid antenna" ( <http: /www.ets-lindgren.com/manuals/Chen_Bilog.pdf> http://www.ets-lindgren.com/manuals/Chen_Bilog.pdf) written by Zhong Chen of ETS-Lindgren. I spoke to the author. He told me when using bilog antennas, if the results do not meet 4 dB requirement, it might not mean the site was not good as the measurement uncertainty might cause the incorrect results. I am suggested to try to use a pair of bilog hybrid antennas to perform volumetric site attenuation after a chamber manufacturer completing its measurement and compare the results. The problem is: I am not sure if I can convince my manager to rent a bilog antenna to try it. I only plan to purchase one bilog antenna if it cannot be used for site attenuation measurement. I figure out it may be a good idea to ask for your experience. I appreciate your input. Best regards, Grace Lin Crestron Electronics, Inc. 6 Volvo Drive Rockleigh, NJ 07647 <http://www.crestron.com/> www.crestron.com - ---------------------------------------------------------------- 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 ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
