Cecil Moore wrote:
Ian White G/GM3SEK wrote:

Cecil Moore wrote:
The Bird is indirectly measuring [(E^for) x (H^for)] as forward
power and [(E^ref) x (H^ref)] as reflected power.
That statement bears no physical relationship to how the instrument
actually works (and "indirectly" won't get you off the hook either).

I was hoping someone would assert such. E^for is proportional to
Vfor which is what the Bird samples. H^for is proportional to
Ifor which is what the Bird samples. Within a 50 ohm environment
that yields forward power. Same for reflected power.

The Bird does not generate a vector cross product. There is nothing
inside the instrument that's capable of doing such a thing.

The hardware displays readings of detected RF voltages - not power. The
forward/reflected power calibration on the meter scale is an external
calculation, based on transmission line theory.

You know exactly how instruments like the Bird work, because at various
times you have posted accurate descriptions here. Your enthusiasm for
your pet theory is making you distort the truth.


--
73 from Ian G/GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek