[LINK] Senator Coonan on 7:30 Report

[Jan Whitaker]

Thanks, Saliya. Do we still have some mainstream media reporters on link?

At 10:33 AM 19/06/2007, Saliya Wimalaratne wrote:
>On Tue, Jun 19, 2007 at 09:17:18AM +1000, Jan Whitaker wrote:
> > At 12:36 AM 19/06/2007, Saliya Wimalaratne wrote:
> > >Another thing that happens with increasing distance is the
> > >necessity of adjusting timing to suit longer distances -
> > >this pretty much doesn't happen with consumer-level kit and isn't
> > >part of the standard(s) as far as I'm aware.
> >
> > Saliya, how can the guy from Optus stand up in front of a camera and
> > say such stupid things about the reasonable use of this 'new'
> > technology for remote locations? Seems to me that if there are dead
> > spots for mobiles because of lack of towers, there will be dead spots
> > for wireless access. Or are they going to pay for high speed
> > satellite data streams? Has anyone seen the detail of this 'new' 'plan'
> > (sic)?
>
>Hi Jan,
>
>Um; because they don't know any better? I've been on the receiving end
>of sales pitches before ('yeah, sure, it will make you coffee, as long
>as you sign here'). I couldn't speculate on <insert seller name>'s
>motives but I'm sure others can :)
>
>In real life, in general, the longer the range, the lower the frequencies
>used (and the lower the bandwidth available per 'channel'). Let's look
>at NextG - 850MHz, thus, not class-licenced - but it will have similar
>properties to current 900MHz kit.
>
>To stay within the 1W EIRP for the class licence, 900MHz kit with a
>max-power transmitter and a small, average sensitivity mobile receiver
>might have a usable radius of about 8km if my calculations are correct-ish.
>
>If the NextG licence allows (for example) 4W EIRP, then the usable
>distance becomes a little bigger - say a 15km radius. But all users
>'attached' to that receiver must share the spectrum - the more users,
>the lower the speed per user. So they're probably better off sticking to
>a lower EIRP and putting in more cells...
>
>Again, to do super-long distances you either need to violate the power
>rules and/or have better (more directional and/or sensitive) receiving kit.
>
>There are guys overseas that have done a 5GHz 300km WLAN point-to-point
>link that they tested at about 5Mbps throughput - but they were using
>600mW of tx power, what is claimed to be 'the best' receive sensitive
>equipment in the world, and what looked like about 35dB of homemade antenna
>gain - an EIRP of about 175W! Not to mention the antenna heights (they
>were, if I read correctly, about 1300m and 1700m)...
>
>Regards,
>
>Saliya

Jan Whitaker
JLWhitaker Associates, Melbourne Victoria
jwhit at janwhitaker.com
business: http://www.janwhitaker.com
personal: http://www.janwhitaker.com/personal/
commentary: http://janwhitaker.com/jansblog/

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