"Bob Nielsen" wrote in message
...
(Jumping in after this argument has gone on for a long time)

This has evolved somewhat into an "apples and oranges" discussion. What
Richard Fry appears to be concerned with is the reflection of a video
pulse by the load (antenna) and its re-reflection (at a later time,
dependent on the length and Vp of the transmission line) by the source
(transmitter) and subsequent radiation (as a ghost image--the effect
repeats, ad infinitum).

While this is certainly a real phenomenon, its effect is a function of
both the mismatch at the load (S11) and the mismatch looking from the
transmission line back toward the source (S22). It does NOT influence
the VSWR and could, obviously, be significantly reduced by the use of a
circulator at either end of the transmission line (which may not be
practical at the power levels of televison transmitters, to use his
example.)

73,
Bob Nielsen, N7XY

To shed more light on this, when I tried to find information in the
literature about transmitter output impedance, I ran across two cases where
reflections from the transmitter are bad. One was the case of multiple
transmitting antennas on one tower; a particular antenna could pick up
another transmitter, and then re radiate it with some delay. The second was
the case of a wide band spread spectrum transmitter, where it is not
possible to have a good antenna match on all frequencies.

Tam/WB2TT