Re: Radiation levels.
David: I would be very cautious about personal cell phones field intensity measurements . The proximity of the antenna is so close to the body (head) that some field intensity values I've heard about approach 200-500 V/.m. The power from such devices is very low but close proximity puts it in the near field and the jury still seems to be out debating what the actual values are. I know a company in this area is modeling the human head with the intention of re shaping the radiation pattern to offer more protection to the exposed body. Another area of concern is high powered airport surveillance radar. The fields generated derive from many megawatts of effective radiated power (erp). i.e. power multiplied by antenna gain. Industry Canada produced a paper called the Electromagnetic Compatibility Bulletin known as , EMCAB -1, and it ran into three issues. It was a survey conducted in 1983 and covered the subject of electromagnetic compatibility urging manufactureres to design immunity into their products because of the EM interaction due to proximity effects. It was well conceived and well researched and has a table of all the expected fields to be expected from users of the EM spectrum. It gave quite a bit of detail as to why EMC was desireable and those needs haven't changed much except there are more devices now and more EMC related problems . This is someowhat off the topic of this discussion group but EMC is embedded in any design where safety is of concern. The fields applied to each service are useful design criteria. The point made in the paper was that it is easier to design EMC into a product than try to fix it afterwards. If interested, I can either scan or copy EMCAB-2 for anyone's use. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment. (After sale) - Original Message - From: David Monreal dmonr...@advancedshielding.com To: emc-p...@majordomo.ieee.org Sent: Wednesday, January 12, 2000 7:41 AM Subject: RE: Radiation levels. Dear answerers, thanks for your kind help. The real cases have been VERY useful. If you have more of them, please send the values to me. Thanks again. David - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Radiation levels.
Dear answerers, thanks for your kind help. The real cases have been VERY useful. If you have more of them, please send the values to me. Thanks again. David - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Radiation levels.
Seems to me it can be almost anything -- AM broadcast stations in the US range from a few hundred watts to 10kW could be much higher (and probably is) in some contries like Mexico.. I've been out of this business for a while, but I remember FM and TV broadcast radiation being listed as ERP (effective radiated power) -- figures I remember in the hundreds of kW. Many orders of magnitude removed from GSM or other cell phones, which I think are below one watt (someone can correct me, but .3W sticks in my mind for US analog phones, but I have no idea about European power levels.) Hope this is useful. Mike Hopkins mhopk...@keytek.com -Original Message- From: David Monreal [SMTP:dmonr...@advancedshielding.com] Sent: Tuesday, January 11, 2000 5:15 AM To: emc-p...@majordomo.ieee.org Subject: Radiation levels. Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy File: David Monreal.vcf - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Radiation levels
David, You may try http://n5xu.ae.utexas.edu/rfsafety/;. Barry Ma Anritsu Company Morgan Hill, CA - Original Message - From: David Monreal To: emc-p...@majordomo.ieee.org Sent: Tuesday, January 11, 2000 5:14 AM Subject: Radiation levels. Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emitting devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy __ Free Internet Access from AltaVista: Get it, share it win! http://freeaccess.altavista.com/pika/www/initweb.jsp - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Radiation levels.
David, Measured 3 to 7 V/m around and inside a building that is within 200-300 feet of the 10KW AM station's three towers. The towers are phased and the amplitude you measure will change based upon time of day as the station changes that phasing. Amplitude is greatly affected by materials, metal, etc. where you take your readings. The distortion to the field is incredible around large metal objects (as one would expect) and can get over 20 V/m in those cases. In this case it was near a 4 foot by 6 foot by 5 foot antique safe in the middle of the building. The amplitude should drop off as the square of the distance (yeah, sure) from the antennas. - Robert - PS Many stations will ask their engineers to come out and make measurements for you at no charge for good public relations. PPS: These measurements were taken in Aptos, California around the three towers for the commercial AM station along Highway 1 (sorry can't remember the call numbers, or exact frequency) If really important, could look for the old report. -Original Message- From: David Monreal dmonr...@advancedshielding.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Tuesday, January 11, 2000 3:24 AM Subject: Radiation levels. Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Radiation levels.
The FCC has records of field strength for broadcast stations (at least AM radio stations) in terms of V/m @ 1km. They're on record at their web site. Typical values for the AM radio stations near me range from 200-1000mV/m @ 1km. Due to power levels antenna style, the results may vary widely. If you extrapolate those field strengths you might get a rough idea of the field strength near the antenna. On Tue, 11 Jan 2000 12:43:32 +0100, David Monreal dmonr...@advancedshielding.com wrote: Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, power cables, etc. The more information the better. David - The V/m guy -- Patrick Lawler plaw...@west.net - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Radiation levels.
According to the BBC transmitter information site http://www.bbc.co.uk/info/reception/tvpb/index.shtml the maximum ERP for 1) A TV transmitter is 1000kW (Crystal Palace and others) 2) An FM transmitter is 250kW (Wenvoe and others) 3) A MW/LW transmitter is 500kW (Droitwich) Transmitters can operate at much lower powers, down to a few Watts for a relay station. Regards Chris Colgan EMC Safety TAG McLaren Audio Ltd mailto:chris.col...@tagmclarenaudio.com -Original Message- From: David Monreal [SMTP:dmonr...@advancedshielding.com] Sent: 11 January 2000 10:15 To: emc-p...@majordomo.ieee.org Subject: Radiation levels. Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy File: David Monreal.vcf = Authorised on 01/11/00 at 16:04:55; code 37f48bf35B15B528. The contents of this E-mail are confidential and for the exclusive use of the intended recipient. If you receive this E-mail in error, please delete it from your system immediately and notify us either by E-mail, telephone or fax. You should not copy, forward or otherwise disclose the content of the E-mail. TAG McLaren Audio Ltd, The Summit, 11 Latham Road Huntingdon, Cambs, PE18 6ZU Telephone : 01480 415600 (+44 1480 415600) Facsimile : 01480 52159 (+44 1480 52159) - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Radiation levels.
David: The field strength at any given point remote from the antenna system can be quite variable and depends on power output, antenna pattern, height of antenna above ground (TV) and whether you're in the near or far field. I've seen levels of 200V/m 200 ft from a 50Kw broadcast array and the Canadian Association of Broadcasters has a software program written in basic to estimate the field from a TV/FM antenna. Canadian Safety Code 6 from Health Canada provides formulae for such estimates. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment (After sale) - Original Message - From: David Monreal To: emc-p...@majordomo.ieee.org Sent: Tuesday, January 11, 2000 5:14 AM Subject: Radiation levels. Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy
Re: Radiation levels.
The only answer I know is that AM broadcast stations are limited to 50 kW ERP, while FM broadcasts are limited to 100 kW ERP. I don't know the limit for broadcast TV, or whether it varies between VHF and UHF stations. Regardless, you must specify the distance from the transmitting antenna(s) in order to calculate resultant field intensity. There are also EIA specs on what quality of reception should be achieved with a given incident field intensity on the receive antenna, but I don' think this is the info you are after. -- From: David Monreal dmonr...@advancedshielding.com To: emc-p...@majordomo.ieee.org Subject: Radiation levels. List-Post: emc-pstc@listserv.ieee.org Date: Tue, Jan 11, 2000, 4:14 AM Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy
Radiation levels.
Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, power cables, etc. The more information the better. Thanks a lot :-) David - The V/m guy - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Radiation levels.
Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy attachment: David Monreal.vcf
