William Chops" Westfield" wrote:
> If you string a set of actual
> conductive copper wires over the same distance, you should surely be
> able to do Better than that, because it's easier to propagate signals
> over copper than over the air.

Perhaps easier in some situations, but you are erroneously jumping from easy
to better or higher bandwidth.

Any electrical transmission line has limitations.  These include a upper
limit on bandwidth and signal strength that falls off exponentially with
distance.

Both these are serious limitations compared to propagating electromagnetic
waves thru free space.  Free space has essentially unlimited bandwidth
considering it's known to support the propagation of gamma rays, which are
way way higher frequency that what we're talking about.  The signal power
only falls off with the square of the distance for radio.  Copper wires can
beat radio for short distances since you can dump more power into the copper
wires than is easy, practical, legal, or safe with radio.  However, sooner
or later the exponential versus squared falloff will catch up to you.  This
is one reason we have microwave towers.  Try sending that kind of bandwith
with the same power input over the same distance using copper cable.


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