I strongly disagree. The heating effect - which is the only scientifically verifiable effect from RF exposure - is far smaller at HF than radar frequencies. Yes, you don't look into a horn antenna of an operating radar transmitter, but a 20 meter dipole is a different story entirely. The exposure limits mandated by the FCC (and by the authorities in this country too) serve only to cover various butts against opportunistic lawsuits.
Vic 4X6GP > On 7 Apr 2017, at 22:55, Gmail - George <[email protected]> wrote: > > Ed & Brian, > My father had severe health consequences from working in a classroom with > operating military radars! > > Since the adoption of OET 65 in the late 90s, all licensees (including Hams) > have had the responsibility to insure their station is in complete > compliance with RF exposure limit guidelines. > > Most likely during your last license renewal or application for a new > license, you checked a box stating you would insure compliance with > non-ionization radiation limits. > Those guidelines are contained in bulletin OET 65. > For Hams OET 65 Supplement B > (https://transition.fcc.gov/bureaus/oet/info/documents/bulletins/oet65/oet65b.pdf) > > gives us some shortcuts to insure compliance without the tedious > calculations. Many of the tables were provided by ARRL & the W5YI Group. > > There are also calculators available on the internet to make it quite easy. > Googleing "amateur radio oet 65 calculator" returned many to choose from. > > The only caveat I will give is that most of the shortcuts and calculators > are for a single transmitting antenna at a specific location. Multiple > radiating antenna WILL change the protection distances - Field Day & group > contesting come to mind! > > Use to be we had to submit OET 65 compliance statements when licensing all > transmitters for Broadcast Stations ranging from 150 MHz to 23 GHz. I > believe we finally could use just a blanket cover statement ; but it has > been a while since I licensed a non-Ham transmitter. > > You do need to insure you are in compliance - to protect your family, > friends, neighbors and yourself. > > 73 > George > AI4VZ > > > From: brian > > "Considered dangerous" isn't quite right. The jury is out of the exact > danger levels of RF for all the various frequencies. These distances > are more of an accepted limit that protects you from inquiries regarding > RF exposure. Pointing to the distances being met helps get you off the > hook. > > People will be surprised to see how small the distances these > calculations are-- especially at lower frequencies. > > One note often overlooked. The distance is defined as the distance from > feedpoint (usually center) of the antenna. > > Also the duty cycle can be considered in the calculation. There are > stock duty cycles for SSB and CW given in the documentation. > > Antenna gain may have to be included. > > It used to be that anything at 100 watts and below at HF was exempted. > I believe that has changed. > > 73 de Brian/K3KO > > > >> On 4/7/2017 16:06 PM, Edward R Cole wrote: >> In the USAmerica ham's now have the *responsibility* of determining the >> safe operating zones for each antenna per FCC regulation. I doubt many >> ever do the calculation. Fortunately Australian ham Doug MacArthur (sk) >> VK3UM (a well known eme'r) has written a program which you can download >> for free. I will simulate the emf fields base on your input data like >> antenna, power, height, band and produces the legal exclusion zones >> where RF exposure is considered dangerous. >> >> http://www.vk3um.com/emr%20calculator.html >> >> Its not hard to use and provides some interesting if not surprising info >> about your station safety. >> >> As I already stated, it is the legal requirement for all US hams to have >> evaluated safe range for humans before operating. >> >> Eg: half-wave dipole, 1400w, line loss 0.5 dB, 14.2 MHz: exclusion = >> 3.06m radially; safe height 2.60m for FCC. Also provides ARPNSA and CEU >> radiation limits. >> >> 73, Ed - KL7uW > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
