All: There was some discussion earlier this month about "Susceptibility testing vs real life."
At that time, I responded to the original poster as follows: A bit over a year ago, I did an extensive field strength survey of TV and FM broadcast stations in Rochester and Brighton, New York. This was done for the Town of Brighton to document existing field strength levels prior to a new TV tower being erected and digital broadcasting beginning. The towers are in the midst of a heavily populated urban/suburban area, and there is lots of interference with home electronics, etc. I am sending you by separate email a jpeg of the plot of the overall results. There are signals peaking as high as almost 130 dbuV/m (3.16 V/m) at distances almost 1 km away, but generally signals, even closer, are under 130 and generally under 120 dbuV/m (1 V/m). At the suggestion of Jim Bacher, I posted the jpeg file to the IEEE EMC-PSTC Forum at http://www.ieeecommunities.org/emc-pstc so that it is now available to anyone who is interested, and registered in the IEEE Virtual Community. Please note that the title says "Calculated" but this only refers to the calculating FS in dbuV/m from the meter reading and the antenna factor. Potomac Instruments field strength meters were used for the measurements along with their provided tunable dipoles. Do not be surprised by the lack of a 1/r falloff with distance. Consider that the broadcast antennas do not have full gain at highly depressed take off angles which corresponds to the region within 1 km or a bit more from the tower. So, the FS in the 0-3km range is a function of both transmit antennas pattern (mostly the vertical pattern) and distance. Therefore, the 1/r won't begin to become apparent until farther away than the distances we measured. Regards, Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Tel: 585 442 3909 Fax: 585 442 2182 [email protected] This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
