On 2014-11-01 22:02:48 +0000, Jeff Liebermann said:

On Sat, 1 Nov 2014 21:14:48 +0000, Percy Picacity
wrote:

However, this does not change the fact that standing waves do not 'use
up' any of the power fed to the aerial (in principle, increased current
intensity increases resistive losses, but this loss can be made
arbitrarily low by having a lower wire resistance). Standing waves do
not in principle use 'power' at all and certainly do not dissipate
energy that otherwise would be radiated. They require a signal to be
applied to the transmission line but, whether the power is radiated at
the other end or the signal merely meets a mismatch, say an open
circuit, the standing wave does not affect, or need to use, any of the
power that leaves the other end. Indeed they work just as well if no
power whatever is used, as in the open circuit case.

I'll make it even easier. An RF signal can only do three things:
- Radiate (as in an antenna)
- Conduct (pass through as in a transmission line)
- Dissipate (convert to heat)
Real transmission line and antenna systems involve combinations of
these three mechanisms. If you run into something that doesn't quite
fit into one or more of these mechanisms, it's probably wrong.

If 'conduct' includes the case where the signal goes to the other end
of the transmission line but does not go beyond it to any other
component, I'll agree with you. In that case, neglecting losses, no
power is used (apart from a truly tiny amount transiently as the wave
builds up and energy is stored in the first few microseconds)

--

Percy Picacity