> My transponder manual says the antenna should be at least 5 feet from any
> organic
material (the crew!)
>
> Dave A227
That sounds like each lawyer who reviewed the install manual added one
foot to the calculated distance. There's a calculator and links to
detailed discussion of health effects at
http://n5xu.ae.utexas.edu/rfsafety/
If above is accurate, my fiddling with it shows a transponder antenna
even inches away from you will not be a problem even at 100
replies/second. The replies are only 21 microseconds long - when your
reply lite blinks, and 50% duty cycle for each burst only if your
squawking 7777 at 84,000 feet. Health effects are proportional to
time of exposure, average power and frequency. A max effective 10us
burst every few seconds for busy airspace, even at peak of 250 watts,
for the sporadic hours we fly appears less than insignificant.
Best,
Fred F.
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