Discussion in 'Amateur Radio News' started by N2RJ, Apr 27, 2021.
This is based on data compiled by the ARRL lab.
Changes to FCC RF exposure rules go into place in May 2021 in the US. I talk about the rules, what's changed and how to stay in compliance. I also describe how to:
- Determine (under the new rules) whether you are covered under an exemption
- Use either of two calculators to perform an evaluation for MPE (Maximum Permissible Exposure) if you wish to or are required to perform an evaluation.
Other videos will discuss using antenna modeling software and field strength measurements.
ARRL RF Safety info: http://www.arrl.org/rf-exposure 2019
FCC R&O: https://www.fcc.gov/document/fcc-maintains-current-rf-exposure-safety-standards
FCC OET 65: https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf
Specific information for radio amateurs (OET 65b): https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65b.pdf
RF Safety and you (PDF): http://www.arrl.org/files/file/Technology/RFsafetyCommittee/RF Exposure and You.pdf
American Cancer Society RF Safety information: https://www.cancer.org/cancer/cancer-causes/radiation-exposure/radiofrequency-radiation.html
RSGB (UK) RF Safety: https://rsgb.org/main/technical/emc/emf-exposure/
In-depth presentation by N9GL: https://www.dropbox.com/sh/mq3djoyqppeucwg/AACjeZjnNjFcDINtEI_B6xPpa?dl=0
Calculator #1 (Evans): http://hintlink.com/power_density.htm
Calculator #2 (Overbeck/Lake Washington): http://www.lakewashingtonhamclub.org/resources/rf-exposure-calculator/
Another calculator (pwr_dens) from K1TR. This is a Windows program: https://www.qsl.net/k1tr/Downloads.htm
More RF calculators: https://www.vpitechnology.com/rf-calculators
Join ARRL: http://www.arrl.org/join
Donate to ARRL: https://www.arrl.org/arrl-donation-form
ARRL Technical Information Service (TIS): http://www.arrl.org/technical-information-service
You did a nice job explaining it to amateur radios operators for their RFR requirements.
I have been training in safety dealing with RF radiation since 1996 and I have trained tens of thousands of Telcom and Broadcast workers. Again you did a great job for the general amateur population by providing this information in the way you did.
It is important to document that your station is in compliance because of neighborhoods and HOAs.
I have seen some pretty nasty situations over the past 20 years. Unfortunately I have been involved representing clients after the fact/ and many of which did not have any documentation of compliance.
So everyone please just "Take a few minutes and do the RF Safety paperwork".
By just checking the box on your 605 does not mean that your station meets all the requirements that are required as part of the RFR/Environmental Assessment.
73 from, The K0UO " Rhombic Antenna Farm"
The possoms and armadillos at my place will not be filing any complaints!
I've also posted the new FAQ at the ARRL Hudson Division website:
It has the video and a PDF with frequently asked questions. The FAQ is a good read.
Good information. I too have been dealing with RFE/MPE since the late 1990's. I found OET 65 easy to understand. I did a lot of roof tops and small cell deployment. Established signs and barriers. When I had a crowded roof top I could call in a specialist. #1 job was to keep the company in compliance. I have signed off on a lot of FAA-FCC-SHIPO-TIPO and the bird watchers forms!
I run an amp on HF-6 meters. I know and have known I know I Need to run the numbers. OET 65B has a nice form to add to your station paperwork. I know my feedline lengths. I will either use a tape measure or use a protractor trick we used with model rockets to figure heights. 10 meters in height is best. That 3-element 6 meter yagi on my deck is a problem.
I have never had my RF safety alarm go off. I did stay well away from rooftop microwave dishes. And who would look into a wave guide? I was far more afraid of wet cells and high current DC circuits.
I wonder how many hams will comply with an assessment. I also wonder how the FCC will enforce such a rule when they don't have the manpower to enforce anything other than the most serious problems. I guess the future will determine compliance. Many hook coax to a transmitter/tuner to some wire and "go to town".
From the 19-126 document:
...The new rules do not impose any significant burdens on the impacted parties because the underlying exposure rules have not changed and the parties' obligations to comply with the RF exposure limits remain the same. The principal difference between the new exemptions and the old rules is the uniform consideration of the distance between the RF source and the location where a human could potentially experience exposure (i.e., separation distance), rather than wholesale exemption of service classes or operational presumptions...
That appears to be the core of the changes. MPE compliance remains the same, while exemption does not.
It would seem like the best and least laborious solution for most amateurs is to simply run one of the calculators (that implements the FCC MPE formulae) across their antenna + transmitter combinations, across the bands they use, to make sure they comply with the MPE rules we have had for years.
Many of us have done that for years, even if we might have been exempt. Thanks to a number of hams who have provided online calculators, it's a pretty easy thing to do.
I suspect the FCC is correct on this point, in that most stations already comply with exposure limits, whether the operators know it or not. Amateur power levels and typical antennas are quite conservative by MPE standards.
Yes, I wonder this as well. I suspect they won't even try unless somebody really raises a fuss about a large antenna installation in a neighborhood where the antenna is very close to neighbors. Otherwise, the service will likely be on the honor system, like they are for all the other rules.
Fortunately for them, many such antennas have terrible efficiency, and main lobes that point very high up into the air, and as such, they will likely comply with MPE limits purely "by accident."
As explained by Dr. Greg Lapin, N9GL, RF safety chair at ARRL, it will only really become an issue if someone complains. If someone complains about your antennas being too close to their home, the FCC can then ask for the paperwork. Or some other governmental authority can invoke that as a reason to deny you permission to erect an antenna. This is where the evaluation comes in. It's basically a CYA.
There was an in-depth presentation I attended and I base the video's material on this. It is here if you want to watch it: