Cecil wrote,

RF energy travels at the speed of light. For the length of time it
takes for the energy to reach the resistor and reflect back to the
source, the source sees 50 ohms. That length of time is not zero.
--
73, Cecil http://www.qsl.net/w5dxp



Even though the length of time is not zero, it's close enough
so that the theorems of network analysis work (at least
at the lower frequencies). Of course, if you want to do a reflection analysis
on a
couple of resistors, each of which is only a minute fraction of
a wavelength long, well, it's a free country. S-parameters assume
reflections and such, and are very useful to the people who use them,
but, as an intellectual tool, it doesn't matter whether there are any real
reflections or not as long as the answers come out right. They
don't really prove reflections in and of themselves, anyway, since it's hard to

prove something based on the assumption that it's true. (I assume it, therefore

it's true.)
73,
Tom Donaly, KA6RUH