> Tom said:
>>Currents on the
> shield can't change SWR inside the cable <
>
> This is very true: however, what they can do is to change
> the indicated SWR, depending on the SWR meter. So you can
> have a cable that in reality has a 1:1 SWR, but has an
> indicated 1.5:1. This fact is not always appreciated..
CM currents can only affect the meter if it is really messed
up and totally unreliable. I've never seen one like that
yet, although I can imagine how one could be made to work
that way. One way that *could* happen is a meter with a
remote indicator and no bypassing on the interface line, so
the shield voltage is rectified and detected by the poorly
bypassed external leads....but that wouldn't be a good meter
to use around any antenna.
Common mode currents cannot affect the SWR reading unless
they are involve a radiating load and they are actually
changing that load's characteristics....but in this case the
SWR is really changing.
73 Tom
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