++++++++++++++++++ Date: Fri, 28 Jun 2002 20:15:20 -0400 From: Brian Murphy To: Cc: Subject: [Elecraft] Re: RF radiation review Hello Daniel, I would suggest the arrl.org site for the best starting place. To my knowledge, some review is always necessary, but a detailed evaluation is explicitly required for higher power and higher frequencies. Usually, hf is fine at 100 watts or lower. This requirement came about the time that the Extra question pool was changed several years ago to accommodate just this law. ARRL should have the particulars and credibility for accuracy of the requirements. I have seen an internet calculator for standard dipoles; you just supply the height, frequency, and dimensions and it calculated the fields that might pose a hazard to living animals and people. I wish I had that site saved. Basically, animals and people should stay a safe distance from radiating antennas, transmission lines, etc. When I tried the calculator, a 30 foot separation from the dipole was deemed acceptable for 1000 watts on most hf bands if my memory serves me well. Of course, QRP is probably safe to within a few inches I would guess (rf levels probably decrease in a 1/(r squared) relationship to distance(r) from wire). But, check the website for the best answers. Hope this helps, Brian N4YTL > From: ham_tech at juno.com > Date: Thu, 27 Jun 2002 23:39:08 -0700 > To: n4ytl at arrl.net > > Hey Brian, > > You had mentioned something about: " rf radiation review now required by > the FCC" > > Where can I find out about this new law? > > Daniel +++++++++++++++++ From: "rohre" To: "Brian Murphy" , Cc: Subject: Re: [Elecraft] Re: RF radiation review Date: Fri, 28 Jun 2002 19:33:32 -0500 For a handy ham antenna radiation calculator that is simple fill in the blank to a few questions, visit the Univ. of Tx. Amateur Radio Club web site, it is linked from ARRL.org under RF safety I believe. 72, Stuart K5KVH ++++++++++++++++++ Date: Sat, 29 Jun 2002 02:50:05 -0400 (EDT) From: kc4kgu at ENTERZONE.NET To: Brian Murphy Cc: ham_tech at juno.com, elecraft at mailman.qth.net Subject: Re: [Elecraft] Re: RF radiation review On Fri, 28 Jun 2002, Brian Murphy wrote: > I have seen an internet calculator for standard dipoles; you just supply the > height, frequency, and dimensions and it calculated the fields that might > pose a hazard to living animals and people. I wish I had that site saved. A quick google search for "RF radiation calculator" yielded the following: http://n5xu.ae.utexas.edu/rfsafety/ --- 73 de John - KC4KGU K2/100 #2490 ++++++++++++++++ Date: Sat, 29 Jun 2002 05:48:52 -0700 From: lhlousek To: elecraft at mailman.qth.net Subject: [Elecraft] Re: RF radiation review <> Only in the far field does the radiation fall off as 1/(rsquared). Close to an antenna it falls off as 1/r. However, exposure limits pertain to field strength not radiation level and, close to the antenna, radiation is not directly related to field strength. The E (electric) and H (magnetic) fields need to be calculated and considered separately. For instance: The E fields can be very high and exceed exposure limits at the ends of elements whereas the H fields would be rather week. Near the feedpoint or a loading coil, the H fields might exceed exposure limits while the E field would not. EZNEC provides a near field calculator that will calculate both E and H fields at specified points near an antenna. These can be compared directly to the regulatory limits after allowing for the duty cycle of the transmission. Lou W7DZN ++++++++++++++++ From: "Sandy, W5TVW" To: "Vic Rosenthal" , "Brian Murphy" Cc: Subject: Re: [Elecraft] Re: RF radiation review Date: Sat, 29 Jun 2002 22:29:55 -0500 Subject: Re: [Elecraft] Re: RF radiation review | Brian Murphy wrote: | | > Basically, animals and people should stay a safe distance from radiating | > antennas, transmission lines, etc. | | Exactly what ill effects have ever been observed from exposure to HF radiation | at amateur (or even BC) power levels? | | Vic K2VCO I'd like an answer to this myself! Especially to HF radio "radiation" from 3-30 mhz! I think this whole thing was started by the so-called hazard of the few milliwatts the cell-phones generate! I worked around 1.5 Ghz satellite (shipboard) antennas for years, but tried not to get right in front of the dish. Most of those systems ran 20-30 watts into a 24Db. gain antenna. 73, Sandy W5TVW ++++++++++++++ Reply-To: From: "Ron D'Eau Claire" To: Subject: RE: [Elecraft] Re: RF radiation review Date: Sat, 29 Jun 2002 21:42:32 -0700 | Exactly what ill effects have ever been observed from exposure to HF | radiation at amateur (or even BC) power levels? | | Vic K2VCO The 'jury is out' on the effects of 3-30 MHz radiation, but one summary and references are available from TRA Electronic Communications at (http://www.traelectronics.com/radmanfcc.htm). This suggests concerns with effects such as "... behavioral modifications, effects on the blood forming and immunological system, reproductive effects, changes in hormone levels, headaches, irritability, fatigue, and cardiovascular effects..." Shoot! I always thought that all of those things were just the natural side effects of staying up all night chasing DX... Ron AC7AC K2 # 1289 ++++++++++++++++ To: elecraft at mailman.qth.net Date: Sat, 29 Jun 2002 23:10:14 -0700 Subject: Re: [Elecraft] Re: RF radiation review From: k6se at juno.com Regarding RF radiation, the following was posted on the Topband Reflector a few days ago by Rich, K1HTV. Let's hope it doesn't get that bad on this side of the pond! 73, de Earl, K6SE ========== Did anyone else catch this item from Q-News Australia, by Graham Kemp VK4BB, as reported on the Amateur Radio Newsline? It doesn't look good for our fellow VK Topbanders or, in fact VK HF ops in general. Talk about a way to reduce the number of active Hams! 73 de Rich - K1HTV - - - REGULATORY: VK HAMS FACE NEW MANDATORY RF EXPOSURE LIMITS Hams in Australia are about to face some of the toughest electromagnetic exposure regulations found anywhere in the world. The idea is to protect people from R-F. Q-News Graham Kemp, VK4BB, has the details as follows: ----- All Australian radio amateurs will be required to know about new Electromagnetic Radiation or EMR controls which are expected to be included in amateur station license conditions from 1 July, 2002. Compliance Level 1 applies to transmitters that are covered by either of these conditions: (a) The total average power fed to all antennas at the site must not exceed 100 watts and antennas must be out of reach. (b) The bottom of the lowest antenna must be at least 10 meters above ground and the average EIRP does not exceed 3200 watts. Compliance Level 2 requires measurements and documented proof of compliance, applies to all other transmitters. EMR in licence conditions It is proposed that the new regulatory framework, to be reflected in the Licence Condition Determinations -- LCDs -- for the Amateur Service and to all apparatus licenses will begin on 1 July, 2002. That means that amateur stations operated under a new amateur license issued on or after that date must comply with the framework. And what about current Australian licensees? They will have until October 1st to bring their stations into compliance with the new R-F exposure rules. (Q-News) ++++++++++++++++++