W5DXP wrote:
Ian White, G3SEK wrote:
[Re-inserting my quote from Cecil]
1. The source is generating 100 watts and 20 watts of the 50 watts of
incident reflected power is being re-reflected in phase from the
source.
The forward power meter reads 120 watts. The reflected power meter
reads 50 watts.

The conventional rule-of-thumb has the source generating (100-30)=
70 watts since it is dissipating 30 watts of reflected power.

2. The source is generating 110 watts and 10 watts of the 50 watts of
incident reflected power is being re-reflected in phase from the
source.
The forward power meter reads 120 watts. The reflected power meter
reads 50 watts.

The conventional rule-of-thumb has the source generating (110-40)=
70 watts since it is dissipating 40 watts of reflected power.

How can you possibly distinguish between the above two identical
conditions caused by different source impedances?

I believe you have specified more numbers than you can actually know.

That's the whole point, Ian. Exactly how are those things knowable
if they give identical readings? I could argue that either of those
conditions exist and you cannot prove otherwise. There are probably
an infinite number of configurations that will yield identical
measurements. What I don't understand is how any of them can be
knowable.


Sorry, I didn't make myself clear. I believe you have specified more
numbers than you can know, in *each* example.

Therefore trying to distinguish between them is double-doomed :-))


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek