-----Original Message----- From: Pettit, Ghery [ mailto:[email protected]] Sent: Thursday, January 13, 2005 8:14 AM To: [email protected]; [email protected] Subject: RE: Question on RF conversion
Lisa, That depends on the gain and efficiency of the antenna. However, for a single data point I measured an old amateur radio HT (Yaesu FT-727R) a number of years ago on both the 2 meter (144-148 MHz) and 70 cm (440-450 MHz) bands in a 10 meter RF semi-anechoic chamber. The HT was placed on an 80 cm high non-conducting table. I connected a speaker-mic so I could lock key the radio for the measurements. On both bands, at a distance of 10 meters, the measured field strength was 1 V/m. If one believes 1/R, then the field strength at 1 meter would have been 10 V/m. Just a data point for the discussion. Ghery S. Pettit, N6TPT Intel Corporation I can second Ghery's observations on personal electronic emitters. I spent some time standing on rapid transit platforms in the SF Bay area, measuring the station RF ambient. I set up my antennas about 2 meters to the side of the faregates, and the highest observed emissions came from cell phones, PCS phones, ham radios, and police handy-talkies. This was certainly not far-field conditions, as the passengers often crowded the area, the faregates were big slabs of stainless steel, and some of the stations were underground. Despite a frequency range of 150 MHz to almost 2 GHz, these passenger-carried devices created field strengths of about 5 to 10 V/M at 2 meters distance. Ed Ed Price [email protected] WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty ---------------------------------------------------------------- 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/listserv/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 Mcantwell [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
