On 20 Dec 2005 10:18:22 -0800, "Ron J" wrote:
I was curious. If a matching network was designed to make the SWR at a
band of frequency less than 1.4 to 1, then what would happen if I
inserted a power sensor on the line with a rated SWR of 1.05 to 1 at
this frequency band?

Would that make my overall system SWR 1.4 + .05 = 1.45 to 1?

Hi Ron,

You leave too many issues unsaid. For one, it seems hardly likely
that you are substituting the load with the sensor, so the sensor must
be on a branch. The branch is going to have to be inserted inline,
and it is going to have its own issues.

You also say nothing of frequency. It doesn't particularly matter as
far as SWR goes, but it goes a great distance in your ability to
flatten the SWR.

You also ask "what would happen?" and that is so open-ended as to be
worthy of a 600 posting thread. Do you really want to be so vague?

You later add that your source can only tolerate a SWR of 1.5 max.
This is too too fragile by half. No doubt you are speaking of
something other that will be perturbed, but I know of no sources that
collapse to their knees under such a mismatch.

And to get back to the nut of the matter, SWRs don't add, at least not
linearly. They would be associated through a root-sum-square process.
However, with only these two numbers, the errors injected by mismatch
are trivial at ±1%.

73's
Richard Clark, KB7QHC