piclist 1999\10\09\043711a >
Thread: re Emissions from Cell phones and Gasoline pumps
www.piclist.com/techref/index.htm?key=emissions+cell+phones
picon face BY : Russell McMahon email (remove spam text)



>the foot of an AM/FM/TV tower.. I think my puny emissions are hardly
>significant in the face of it's multiple 10-50kW outputs.


But watch for the inverse square law.

A 2 watt cellphone output (car phone, not hand held) and a 10,000 watt
transmitter have a 5000:1 power ratio. BUT the equivalent power diminishes
by the square of the distance

The square root of 5000 is about 70 so a 10kW tx at 70m is matched by a 2w
cellphone at 1m or a 500mW cellphone at  0.5 metre. When walking near a
petrol pump with your phone on you run the risk of it transmitting
autonomously (which happens eg during receipt of an incoming call) and you
then have the same result as a 10kW transmitter across the road or a  1 MW
tx at 1 Km or so distance.

Arcing is most unlikely to be a problem under this scenario but certainly
some equipment can be affected by RF of this power at this range. It may not
pass current EMC susceptibility requirements but then chances are we don't
pass the requisite flammability specs if something does go wrong :-).

I would have thought that there would be regulations to prevent high power
transmitters and petrol stations being located adjacently.

Regulations in NZ also limit cellphone use on airplanes. One of out noisier
and arguably less intelligent members or parliament was fined quite some
years ago for using a cellphone from a public passenger aircraft aircraft.
He is now retiring from parliament and on the radio yesterday he was making
comments which show that he still doesn't understand the POTENTIAL risk that
he was exposing people to by using his phone. Still seems to think that it
was all a fuss about nothing.




     Russell McMahon
_____________________________

>From another world - http://www.easttimor.com

What can one man* do?
Help the hungry at no cost to yourself!
at  http://www.thehungersite.com/

(* - or woman, child or internet enabled intelligent entity :-))

From: Dave VanHorn <dvanhornEraseMEspamKILLspamCEDAR.NET>


>>Because RF emissions are everywhere and at a never predictable
>> level: the petrol station next to the local FM broadcasting antenna; next
>to
>> a ham radio operator; the passing police cruiser, the CB operator
>
>Good point, we have a large gas station here in town that is literally at
>the foot of an AM/FM/TV tower.. I think my puny emissions are hardly
>significant in the face of it's multiple 10-50kW outputs.
>

<026301bf1231$2f635640$db3561cb@mkbs> 7bit

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