FCC reviews RF exposure.

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ShowMaster
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FCC reviews RF exposure.

Post by ShowMaster » Thu Apr 04, 2013 9:01 pm

New limits being defined for frequency vs power levels that are safe for extended times.
Unfortunately it's over 200 pages of text but hopefully it'll be sorted out by other interested parties. Being that FPV can be for 30 min of more with frequencies and elevated power levels that could be cause for concern, it could be worth knowing what these levels are and how to fly safer. I see many with the booster or higher powers UHF antennas installed on their tx holding the antenna close to their faces while flying. Maybe not a good idea? Of course it takes years for the mistakes we made to sometimes surface, like sunburns when we were younger.
I'm hoping the report relaxes the concerns instead of it going the other way.
A lot to read!
http://transition.fcc.gov/Daily_Release ... 3-39A1.pdf




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Rusty105
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Re: FCC reviews RF exposure.

Post by Rusty105 » Thu Sep 12, 2013 12:31 pm

This topic may be a bit stale, but I can shed some light on this. From what I know about long range FPV, just getting back into RC, 430 MHz is a popular control frequency. As an amateur radio operator l have to occasionally check RF exposure limits when upgrading equipment. There are several online RF calculators, some will also tell you if you are in compliance, however the levels may be outdated. You can try this one http://hintlink.com/power_density.htm.

For what it's worth 430 MHz with 2 watts into a 6 dBi at 2ft is over the limit for an "uncontrolled environment" but OK at about 2.5ft

Rusty

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ShowMaster
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FCC reviews RF exposure.

Post by ShowMaster » Thu Sep 12, 2013 3:27 pm

It comes down to each individuals bodies tolerance to rf exposure. Like smoking and drinking, sun exposure, some of us react more than others to it all.
The published levels of exposure are guidelines not some magic line drawn to cross or not cross.
As with all of life's experiences we usually don't know the final outcome until we're much older. I'm sure those older persons we see with all the serious preventable conditions wish they had taken more precautions when they were young.
So as the lawyers signs always says " do this at your own risk" and worry years later.
The young are super humans, but then they get older they sometimes wish they had been more careful.

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Redbrickman
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Re: FCC reviews RF exposure.

Post by Redbrickman » Thu Sep 12, 2013 9:28 pm

EU has 100mw power limit on a 2.4ghz Tx and the rest of the world 200mw. Can't see why 200mw would be required anyway as 100mw on the 9x or Taranis will take me beyond visual range.

In 40 years time the medical experts will probably be telling us that years of exposure to the wifi "cloud" has damaged us in some way.

I have no doubt that many who use their cell phones stuck to their ear for long periods of time daily will find they have neurological problems in later life. The experts tell us their is no danger at the moment but they have only looked at the RF heating effect and not what the RF does to our brain chemistry after long exposure times.
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Flaps 30
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Re: FCC reviews RF exposure.

Post by Flaps 30 » Thu Sep 12, 2013 11:11 pm

Exposure to cell phones does have a negative effect on your mental health, and your ability to stay aware of your surroundings whilst using one. Having seen people driving in an erratic way and pedestrians not being aware of what is around them when they are on the phone, shows to me that the RF must be causing some blockage to the senses at the time of operating them.

The subject of RF exposure levels has been doing the rounds for many decades. It is becoming a concern because of today's society seems to try and claim damages for anything and it is the lawyers that are the driving force, and it is them that are pushing up the cost of insurance as they trouser millions of £'s/$'s at our expense.

In my lifetime I have been exposed to RF levels that lights up fluorescent tubes without them being plugged in. Not to mention having my head inches away from tank circuits operating at 1000+ Watts at 500Mhz No problems found.


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ShowMaster
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Re: FCC reviews RF exposure.

Post by ShowMaster » Fri Sep 13, 2013 2:09 am

Except craving Rc flying.

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rperkins
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Re: FCC reviews RF exposure.

Post by rperkins » Fri Sep 13, 2013 2:29 am

Flaps 30 wrote: In my lifetime I have been exposed to RF levels that lights up fluorescent tubes without them being plugged in. Not to mention having my head inches away from tank circuits operating at 1000+ Watts at 500Mhz No problems found.
I agree . Although some people may say it has effected me :)

Earlier I had typed up a response along this line but ended up not posting it. ( I did some research on the dBm levels I was mentioning and it wasnt applicable, I didnt realize bluetooth headsets were so low an output, thats probably why they dont work outside in the sun ) Anyway, I saw the fluorescent tube trick at one of the legacy high power AM broadcast stations WLW 50,000 watts . http://en.wikipedia.org/wiki/WLW . they also had a power transformer that was so big that you could 'hear' the announcers voice in the transformer 'hum' . I worked in an RF screen room for nearly 5 years injecting RF into pagers when reparing, recrystaling, aligning, and testing them. We've had RF running through us for nearly 100 years now, plus whatever the suns rf content is.

Who is in the most (common) danger from rf exposure IMHO. the food service worker who stands in front of a running microwave 8 hours a day. Even new microwaves leak pretty bad when viewed on my http://www.ubnt.com/airview. Then I would be concerned about the close proximity of the cellphone to the ear and the brain. They do take steps to reduce that problem and got plenty of lawyers to back them up. I dont think the normal RC enthusiast has much to worry about from RF. Spinning props, yes. RF no.

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jhsa
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Re: FCC reviews RF exposure.

Post by jhsa » Fri Sep 13, 2013 10:51 am

Yeah, I think spinning props are definitely worse for your health. They also are dangerous because of RF. They are Rotating F****** :mrgreen:
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