[TowerTalk] FCC RF Safety Regs Info Sept 1

Fractenna@aol.com Fractenna@aol.com
Sat, 2 Sep 2000 04:01:00 EDT

In a message dated 9/2/00 3:47:11 AM Eastern Daylight Time, 
kh7m@hsa-kauai.net writes:

<< 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!


Chip N1IR

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