My guess for the reductions: Since the frequency bands are for broadcast television and FM radio, the sources are not portable, and the field strength levels at the boarders of the broadcast transmitter location are regulated and thus known to be at the lower level.
The biggest hazards for radiated immunity outside of military and civilian aircraft (radar immunity) are usually portable sources (cell phones and two-way radios) not operating in these bands, though the top end of the UHF TV band is getting eaten away by cell phone service providers. Don Borowski Schweitzer Engineering Labs Pullman, WA "Gordon,Ian" <[email protected]>@majordomo.ieee.org on 03/03/2003 05:01:09 AM Please respond to "Gordon,Ian" <[email protected]> Sent by: [email protected] To: "'IEEE EMC-PSTC GROUP'" <[email protected]> cc: Subject: RADIATED IMMUNITY REQUIREMENTS FOR EN61326 Everybody Can you advise me as to whether the same reduction in field strength is available when applying the industrial immunity requirements of EN61326 as when applying the generic industrial immunity standard EN61000-6-2. EN61000-6-2 permits a reduction in field strength from 10 to 3 V/m over the following frequency ranges : 87 - 108 MHz 174 - 230 MHz 470 - 790 MHz Furthermore, I have never been able to work out why there is a relaxation at these freqs. The wording from table 1 of EN61000-6-2 is ....10V/m........ "Except for the ITU broadcast frequency bands (given above) where the level shall be 3V/m". Can anyone provide the "logic" behind this clause? (I'm sure there is some!). Thanks Ian Gordon 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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
