Yes that will work too. I like the SNA or VNA because they calibrate out the cable loss. As I understand it, one connects the RX and TX antenna cables together and then performs a two-port cal. Then connect the cables to their respective antennas and read S21 or S12 (should be the same either way). Then only the AF needs to be factored in.
If I understand the OATS cal procedure, the RX antenna height is moved from 1 meter to 4 meters and readings are taken. Now this is the strange part: The readings are averaged. Is this right? Now think about it- when a DUT is tested, the RX antenna is moved until maximum signal is achieved- not the average signal as the RX antenna height is swept. This method makes a DUT look "hotter" than it really is and makes the site uncertainty appear larger. If the cal consisted on taking only the maximum signal, then the correct height could be determined by simulations and the antenna could be swept close to this height. Much less data to take. These antenna heights will of course be different for horizontal and vertical polarization. Dave Cuthbert Micron Technology From: Luke Turnbull [mailto:luke.turnb...@trw.com] Sent: Monday, June 23, 2003 2:24 AM To: emcp...@aol.com; emc-p...@majordomo.ieee.org; drcuthbert Subject: RE: another OATS question Or a Spectrum analyser with tracking generator. >>> <drcuthb...@micron.com> 06/20/03 06:58pm >>> Renting a VNA or SNA would really speed things up. Dave From: emcp...@aol.com [mailto:emcp...@aol.com] Sent: Friday, June 20, 2003 10:02 AM To: emc-p...@majordomo.ieee.org Subject: another OATS question Hello everyone, I have worked with sites that used the hardware cloth (screen) over concrete in the past. When the tears would happen, they would patch that area with screen to cover the hole and maintain continuity. Can this patching create a problem with site attenuation, if there are too many patches? I was planning to build the site with concrete underneath the screen. Also, do you know of a way to do the site attenuation faster? In the past, I have used tunable dipoles (takes forever) and also broadband antennas, which is a little faster. Normally, I have done the site attenuation with the signal generator about 10 feet behind the transmitting antenna. This means that you have to go outside, change the frequency, go inside and make the measurement, then back outside again. All I have to work with is a signal generator and spectrum analyzer. Would it make a difference to have the signal generator inside the building (this means that the output cable to the antenna would be approx. 30 feet long.) I guess as long as this long cable for the transmit antenna is counted in the "V direct" reading, it should be ok? Making site measurements faster will help me evaluate my proposed site location. Thanks for your input. Tim Pierce 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
