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[TowerTalk] Re: Upcoming Compliance

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Subject: [TowerTalk] Re: Upcoming Compliance
From: (MarchandJohn)
Date: 18 Nov 1997 12:11:36 -0400
Hi Brian,

I ran that RF Safety program for every radio/antenna/pwr level on every piece
of equipment I own (160mtr-450mhz, including mobiles) and didn't come anywhere 
close to the controlled/uncontrolled limits for each band. But, I dont run a
big honkin' amp anyway.
Do the controlled/uncontrolled parameters relate to near field/far field? 

I think if you get into a marginal situation, then you would start looking at 
feedline loss to get the numbers closer to reality.

-IMHO- If you calc everything in a lossless environment and fall within the
spec, then you would have the argument that your system couldn't even come
close to those limits due to feed line losses etc. 

As far as standing 2 ft away from 1.5kw -- well his brain is most likely
already fried, so it really doesn't matter.... but it'll keep his coffee warm 

Just an opinion
John K1RC
35 mi NW of Boston

From: on Tue, Nov 18, 1997 11:03 AM
Subject: Re: [TowerTalk] Re: Upcoming Compliance

I'm curious about the RF safety calculator assumptions.  The area of
interest in in the "near field"  My understanding is that calculating
near field  field strengths is a big task.   The antenna pattern DB gain
are far field numbers?  Aren't we mixing apples and oranges?  I question
any "calculation" that says it's OK to be within 2 feet when running 1.5

Anyhow if it does become a standard, don't forget to include your
feedline loss.  1db is 25% power that doesn't make it to the antenna and
should not be included in the calculation.


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