Subject: (Fist) The LAN "blue world" characteristics......
Date: Thu, 1 Apr 1999 010903 -0600 (CST)
From: "Roy L. Beavers" <rbeavers@llion.org>
To: emfguru <rbeavers@llion.org>
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.......The question about "wireless computer" networks in a school room
has generated a surprising amount of response.... I don't consider the
responses very reassuring???!!!..... Not for the school children......
Where (who) is the responsible institution here???.......
It still looks like this could be a good deal of Ghz "blue world"
concentrated in the school room of unsuspecting children (parents)......
Roy Beavers (EMFguru)
rbeavers@llion.org................
...It is better to light a single candle than to curse the darkness...
.................PEOPLE ARE MORE IMPORTANT THAN PROFITS...............
---------- Forwarded message ----------
Date: Thu, 01 Apr 1999 10:03:21 +1000
From: Stewart Fist
To: "Roy L. Beavers"
Subject: Re: (Reuss) Re: (Itzikowitz) wireless computer network (fwd)
The NII Band proposals are best considered as just an extension of the 802.11
WaveLAN system, using the ISM frequency bands over distances of a few
kilometres (equivalent to a cell phone) back to another site (usually an ISP's
premises). They will also use CDMA techniques at low power levels.
In America the proposals go under the name SuperNET, and the transmitter power
originally proposed was upt to 1 Watt (10 to 15 km range), but later the FCC
cut this down to 0.1 Watt (the request came from the WINForum group led by
Nortel and AT&T who wanted to cut the range back to 50—100 meters so as not to
compete with wireline systems) which most people think is too little. I
haven't heard whether they compromised.
The techniques are based on 'spectrum sharing' and data packets, with spectrum
sharing etiquette ("listen-before-talk") for bandwidth allocation only on
demand. This means they can stay active all day to receive, but only transmit
in very short bursts.
In Europe the development is called HiperLAN (High Performance LAN) being
developed by
the European Telecommunications Standards Institute.
ETSI also extends this to make it an alternative to the IEEE's 802.11
specification for wireless LAN. They are proposing higher data rates and the
ability to operate in the 5—17GHz radio band at a data rate of 23.5Mb/s --
which will mean very short transmission periods indeed (fractions of a second
in most cases).
HiperLAN products won't be available until late 1997.
In both cases the output, at the most, will be very short bursts at CDMA
cellphone power levels (lower than existing), and the transmitting unit will
be probably be on the outside of the house or office metres away from the user.
The main potential problem here is that they offer free bypass of the local
telephone companies, and so could become very popular. However even with 100%
use by Internet surfers, the total EMF pollution would be much less than
cellphones, on present indication -- and certainly much less harmful to the individual.
--
Stewart Fist - writer and columnist
See http://technology.news.com.au/opinion/
http://www.abc.net.au/http/sfist/ (some archives)
http://www.electric-words.com (main archives)
70 Middle Harbour Road, Lindfield, 2070, N.S.W, Australia
Phone +61 2 9416 7458 Fax +61 2 9416 4582
Archive provided courtesy of WaveGuide, http://www.wave-guide.org
Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html