[TowerTalk] RF Fields

[K7GCO@aol.com]

In a message dated 9/4/00 5:10:39 AM Pacific Daylight Time, 
w8ji@contesting.com writes:

<< 
 > I saw an article about W5UN with 1.5 million watts ERP on 2 meters into a
 > 30 dbd array.  How far does he have to move his house (shown on the cover
 > next to the antenna) to be in compliance with the new radiation rules? 
 > (you wouldn't expect him to lower his power would you?) 73, Ken W2DTC
 
 When the physical size of the array is large compared to the 
 distance of measurement, and current or "power" is distributed 
 somewhat evenly in the array, the field intensity is actually less 
 than with a smaller array with the same applied power. 
 
 Visualize the radiation of 1500 watts of energy (that's the MOST 
 power you can have, no matter what the antenna "gain" is) from 
 that large antenna, and the portion of it concentrated in a small 
 area as you move around in front of the array. Most of the radiated 
 field "misses you", and it acts like you are in front of an small 
 section of that antenna with much lower applied power.
 
 At a distance where that antenna starts to "look like" radiation 
 comes from a single point in space, all of the energy arrives in 
 phase.
 
 He is much more likely to be in trouble at his neighbor's house 
 than his own, but I doubt he points the antenna along the ground.
 
 He'd have far more FS in a small area of his house with a small 
 array pointed at a small area of his house than that big array in the 
 back yard pointed at the entire house and overlapping the sides. 
 73, Tom W8JI
 w8ji@contesting.com
 
 - >>
Tom:  Your explanation has some merrit but if I lived in that house I'd like 
to have you as a test medium in that field for a long peroid of time--I need 
to be sure.  If you can still spell dB after some time I'd consider it at 
least W8JI safe.  We may never know the full affects of certain fields unless 
they really cook you.  I avoid them all when possible.  25 years from now 
those that assured various things were safe that prove not to be, present an 
irreversible problem.  Those who mislead us based on short term tests 
frequently aren't around to take the consequences like the Cigarette Co's.  
As far as all those rats or mice they used for testing--I think we need a 
stronger breed of test rats and mice.   

In case you haven't been doing your medical reading, asprin isn't as safe as 
it was once proclaimed for 50 years either.  My mother quickly lost her 
hearing using it fully prescribed by a doctor.  It finally has warning lables 
on it now.  What it supposedly reduces in heart attacks it makes up for in 
strokes.    
 k7gco

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