On 10/12/2015 4:45 PM, joe wrote:
gareth wrote:

The forward and reflected waves in transmission lines and antennae do not
affect each other by the principle of superposition (although they act
together to
give an apparent (and only apparent) standing wave.


Please allow me the liberty of rephrasing your sentence as follows:

The forward and reflected waves in transmission lines and antennae do
not affect each other. However, by the principle of superposition they
act together to produce a standing wave.

(Superposition is the adding together of two or more stimuli to produce
one response.)


Why, then, should a transducer connected to one end of a transmisison line
(such
as the PA stage of a TX) be affected by the apparent VSWR, as we know that
it is,
but why does not the principle of superposition apply in this case?

You have energy travelling toward the PA (the eflected wave. It has to be
dissipated. That adds heat to the PA.


No, it does not have to be dissipated. Most of it is reflected back
toward the antenna by the transmitter's output network. There may be
some dissipation at the transmitter, but that is due to losses in the
network.




Just curious.

(The enquiring mind - the mark of the _REAL_ Radio Ham)

You really should try to use google and look things up that interest you
rather than try to initiate discussions for the sake of discussing
something.

You really should learn to understand and use the Smith chart. I know,
it has a bit of a learning curve associated with it for the uninitiated,
but you could greatly benefit from studying it.