Olympus-OM
[Top] [All Lists]

Re: [OM] Earth Hour

Subject: Re: [OM] Earth Hour
From: Jan Steinman <Jan@xxxxxxxxxxxxxx>
Date: Wed, 1 Apr 2009 22:44:31 -0700
> From: Ken Norton <xra@xxxxxxxxxxx>
>
> Jan the Ham wrote: >But there are many orders of magnitude difference
> between them!
>
> True, but they are also cumulative.

Fair enough. A microwave and a cell phone are both intermittent use,  
but wifi is 24/7/365.

> As I sit here at my desk three and a half hours past the end of the  
> normal
> business day when there are only a couple dozen people in the building
> working, my Fluke spectrum analyzer at my desk is measuring a noise  
> floor of
> between -61 and -52 dB.

Yikes! Perhaps you can build a screen room? :-)

Question about units: is this actually dBm, in other words, dB  
referenced to a milliwatt? Or is it dBµ, referenced to a microwatt?

A decibel is just a fancy ratio. It is dimensionless. Unless you refer  
to some reference, dB by itself doesn't say how much energy is being  
measured.

> Wifi is between the two. You get no more than milliwatts exposure from
>> wifi, even when sitting on your lap -- roughly 1,000 times less  
>> energy
>> than that emitted by a cell phone. And yet, some people who use cell
>> phones with abandon claim wifi somehow hurts them.
>
> LOL, maybe YOUR WiFi equipment.  :)   I take mine right up to the  
> legal
> limit.

I don't have the FCC code in front of me, but if you're talking  
"legal," I believe you're limited to 500mW.

>  (That's my story and I'm sticking with it--ahem, don't mind the
> +18dB antennas...).

Think "jelly sandwich." The more you spread it, the thinner it gets,  
and the more you bunch it up, the thicker it gets.

So-called "gain" antennas provide apparent gain by changing the  
radiation pattern from that of an ideal uniform omnidirectional  
radiator. So if you boost the radiated power 18 dB in one direction,  
you're cutting it by that much in other directions. So just don't  
point that thing at your head, and you've actually *reduced* your  
exposure by using a gain antenna.

> You should see what a room full of Blackberrys will do to the RF  
> space!


I believe it. Doesn't mean I care to experience it!

:::: Magic: using envisioned intent and directed action to select your  
desired future path from among the infinite ones available. ::::
:::: Jan Steinman, Communication Steward, EcoReality: http://www.EcoReality.org 
  ::::



-- 
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz