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Old October 4th 03, 07:52 PM
Tarmo Tammaru
 
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"Reg Edwards" wrote in message
...

Reg, that can't possibly be you. Someone has hijacked your e-mail.

===========================

Ian, it IS me! Please calm yourself.

Let me put what I said into somewhat different words.

SWR meters are designed to operate and provide indications of SWR, Rho,

Fwd
Power, Refl.Power, on the ASSUMPTION that the internal impedance of the
transmitter is 50 ohms. It makes the same INCORRECT assumption as a lot

of
people do. This should not be surprising because it was people who

designed
it.

So SWR meters nearly always give FALSE indications about what actually
exists.

Perfectionists may be upset at the repercussions of this alarming

statement.

PS: In the whole of his excellent 236-page exceedingly comprehensive
volume, Chipman, in 1969, makes not the slightest mention of SWR meters.
----
Reg, G4FGQ


Reg,
The SWR meter knows only by how much the load deviates from 50 Ohms.
Somebody has very cleverly interpreted this, and calculated how the meter
scale should be labeled. Actually, the SWR/Power meter has information that
is not displayed. For instance, for a 2:1 SWR it has the needed information
to differentiate between a 25 and 100 Ohm koad, but to display this
information would require adding extra parts

BTW, I did force the SWR meter to see a different source impedance. There
was no difference in SWR readings for either the 1:1 or 2:1 case.