PoP wrote:

On Tue, 30 Sep 2003 10:00:03 +0100, The Natural Philosopher
wrote:


If everybody used gigabit wirelss to connect up their home networks,
there would be horrendous problems with adjacent properties


Not necessarily.With current technology maybe that's true, but I
imagine in the years ahead the wireless options will expand and the
wireless devices will be hugely more configurable.

Model aircraft don't have a problem flying together, unless some divot
happens to choose the same frequency as someone else.


Don't be dumb. Bitrates on model aircfat are at best 2400 baud, and
limited to about 30 channels on the band. Channels are 10Khz apart, so
useable BW is les than 5Khz. You won't get 100Mbps on that.

The ONLY way to get higher BW on radio is to use ever higher frequencies
- cellphonse use 900Mhz or 1.8Ghz, WiFi is 2.4Ghz, and even then, its
gettng crowded.

Waveguides - be they wire, hollow pipes, or glass fibres, allow the use
of the same carriers and the full broadband spectrum without
interference. They will ALWAYS be able to carry more signal with less
interference than an equivalent broadcast system at similar bandwidth.


You can get at least 8 GBPS down a fiber. The best of microwave
technology using large aerials and big towers and highly directional
links, is a few hundred Mbps at best.

Wifi as currently constituted is a shared space collison detectieon
'Ethernet' of typically 10Mbps, up to maybe 50Mbps. Any piece of cat 5
will do 100Mbps short range and no collision problems at all if a switch
is used and there is no coincidence of traffic between nodes.


You only hgave to listen to e.g. a cellphone qality versus a decent
analog or digital phone over landlines, to hear the difference between a
clear unobstructed 64Kbps channel and a highly contended bandwidth
limiteed compressed to the nth degree and frequency spread system.

Bandwidth is always tight with radio. There is never enough space to do
what you want. Sometmes its a cheap way to elimninate wires or fibers,
but its never ever the BEST way for a duplex system. Broadcast? yes. It
works well for TV and radio, it basically sucks with bi-directional data.

It is however, a very cheap way to work if limited performance is
acceptable, and the cost of laying lines is exceptionally high, which is
why half of the long haul data in this country goes via microwaves.
However, these are getting congested already, and fiber is the answer -
it just costs a ****load of money - mostly in terms of obtaining
permission - to lay it.

If you have a chance to rewire, lay in cables, or better still, fiber.

I wnxer why we still have TV downleads. Surely we should be able to do
it by wireless links :-) In fact, I wonder whay we still use any cables
at all. :-) :-)

Cos they work BETTER than most other things at delivering a clean signal
through and unpredictable environment.





PoP