[TowerTalk] FCC RF Safety Regs Info Sept 1
Sat, 2 Sep 2000 04:01:00 EDT
In a message dated 9/2/00 3:47:11 AM Eastern Daylight Time,
<< Chip wrote, in part:
> I have serious concerns about the 'dummy' compliance
> calculators that are making the rounds.
Is this the calculator of which you have concern, Chip?
ARRL is referring its' members to this site as one way
to determine compliance. I have used it, and am
satisfied that my situation is in compliance. But.....
I do not know the depth of the analysis behind.
There is much else about all this at the ARRL web site
open to all at:
Lots of links to info on the topic give there.
73, Jim, KH7M
Yes it is. I see in this version that it DOES have a disclaimer about near
field /far field. What it SHOULD say is THAT IT CANNOT BE USED for ANY near
field calculations. So if you try your 80M vertical and see a cutoff of, say,
6 feet DON'T BELIEVE THE NUMBER! You are well within the near field.
It is VERY EASY to get --what they call'--'hotspots' in the near field. These
can have an equivalent 'gain' far , far higher than the far field max gain.
Look: just keep out of the near field, and use the calculator as the WORST
CASE SCENARIO for the far field. But if you get a calculated cutoff distance
which is a very small fraction of a wave THEN DO NOT USE THIS VALUE IN ANY
I cringe to think that someone will be using this calculator to say that they
can be within a few feet of an 80M vertical at 1500 watts!
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