Oh, understood now.
For 100m link inside the building, with a right antenna and an
american office bulding style (cubicles, concrete or iron structure
and a lot of glass) you need no more than 15-20dbm power at 2.4GHz.
And still don't recommend to any human living permanently near the router...

Vasile

On 10/15/06, Mat <list@piccoder.co.uk> wrote:
> 11W is the power supply limit, not the radio power limit! Sorry that wasn't
> very clear at all, however we do have another limit of 2W transmitted energy
> on the radio, amongst other legal limits I still need to work through.
>
> Mat
>
> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
> Vasile Surducan
> Sent: 15 October 2006 14:44
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] Radio Synchronisation
>
> 11W inside of a building means suicide for the people living in the
> office where the transmitter is installed.
> I doubt he read the standard before claiming he can use 11W.
> I even bet.
>
> Vasile
>
> On 10/14/06, Denny Esterline <firmware@tds.net> wrote:
> > Maybe I missed something - this sounds too easy.
> >
> > Power at the transmitter is effectively unlimited, right? (o.k. 11 watts,
> but that's still lots) Why not just send a time signal out continuously, and
> let the receiver read it whenever it wakes up? The transmitted data stream
> could be a time packet followed by some form of sync pulse - something like
> $5A5A, then the reciever snychronizes with the next rising edge.
> >
> > I'm more interested in why the units need that level of sync.
> >
> > -Denny
> >
> >
> >
> >
> > > I'm currently working on a design with a specific problem, which I'm
> > > hoping someone will have come across before.
> > >
> > > Essentially I have several remote circuits, which must remain
> unconnected.
> > > They all need to be synchronised within 100 Micro Seconds.
> > >
> > > Essentially we are looking at deploying a beacon transmittor which will
> > > send out a pulse at known intervals and have low power recievers on each
> > > circuit which come out of hibernation at the required interval, to reset
> > > the onboard clocks appropiatly.
> > >
> > > We are looking at achieving 100m range (indoors), however power at the
> > > beacons is not a significant problem (we have 11Watts available, and
> these
> > > are not battery powered). Power at the recievers is crucial, each
> circuit
> > > is powered by battery and must be capable of running for a minimum
> period
> > > of a year. Physical battery size is not crucial but small is better :)
> > >
> > > Does anyone have any other suggestions how to achieve the required
> > > synchronisation, or can anyone suggest any suitable radio IC's/circuits
> > > which could be used as I am stuggling to find anything useful via google
> > > (must be using the wrong keywords)
> > >
> > > Any suggestions or comments would be greatly appreciated.
> > >
> > > Mat
> > >
> > >
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