Gilmer, Mike wrote:
>However, this 50ohm SWR meter is not "on the cable". It's in its own
>world, on the near side of the 50-to-93ohm impedance step. So it
>doesn't see the standing waves that are on the 93ohm cable, does it?
>Rich contends that the SWR meter will READ 1:1. Maybe it will. But
>that is not the REAL SWR "on the cable"; it's just what the meter
>reads.
Mike,
It sounds like you have it pretty good. Yes, there is a standing wave on
that 93 Ohm cable. But if you take the cable and 50 Ohm load as the
black box that you orignally started with we see it's input impedance as
50 Ohms. Basically standing waves are created whenever there is a shift
in impedance. You have to look at each impedance interface. The swr
meter/cable junction is one interface, the cable/load junction is the
other. The standing wave along the cable is contained within the cable -
the meter will never see it since it measures effectively forward vs.
reflected power through it.
But it sounds like you have at least as good an understanding as the rest
of us!
73,
Jon
KE9NA
--------------------------------------------------------------------------
The Second Amendment is NOT about duck hunting!
Jon Ogden
jono@enteract.com
www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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