For emissions testing, the antenna should have a well balanced design when used over a ground plane. Perhaps the antenna you are considering is not well balanced. The balance issue shows up in the vertical orientation when there is coupling to the ground plane and is not unusual in some bicons. I am assuming that you will install a removable ground plan for FCC and ETSI emissions measurements.
Richard Woods ---------- From: Tudor, Allen [SMTP:allen_tu...@pairgain.com] Sent: Wednesday, November 15, 2000 11:36 AM To: emc-p...@ieee.org Subject: Which Antenna? Greetings, I am having a fully anechoic pre-compliance test chamber built. By fully anechoic, I mean ferrite tiles will be installed on the floor as well as the walls and ceiling. The inner dimensions of the chamber will be 24 feet long by 14 feet wide by 13 feet high. The chamber will be used for radiated emissions as well as radiated immunity. Radiated emissions testing will be from 30MHz to 1GHz. I am looking at a biconilog antenna that can be used for emissions and immunity testing. However; for emissions measurements, the salesman recommends that I use separate biconical and log-periodic antennas. He says that if I use the biconilog antenna for emissions measurements, there will be some coupling to the ground plane when the antenna is in the vertical position. However, this chamber will have ferrite on the floor, so I don't know if that is a valid argument. Aside from the expense of two additional antennas, I have two conflicting concerns. 1. I would rather not have to work with more than one antenna if I don't have to due to down time and possible damage to an antenna. 2. On the flip side, I want to make sure that I have repeatable results, especially at the low end of the spectrum. Any advice would be greatly appreciated. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org