On 20 Dec 2005 10:42:14 -0800, "Ron J" wrote:

Hi Cecil,

Thanks! I try to explain the affect of the power sensor even if it is
ideally very minimal. My main concern is that at the band of design
frequency the transmitter is only designed to handle 1.5 SWR max. I'm
afraid that I might break it since our matching network already changes
the SWR to a peak 1.40 to 1 at certain frequencies on the band.

I may have other idea. If I add the return loss of the devices, would
that allow me to somehow find the SWR?

As others have told you, no, the system isn't analysed as simply as
you suggest.

Some thoughts:
- your concern that your transmitter will suddenly degrade at VSWR=1.5
is probably unfounded;
- if your power sensor is intended for inline monitoring, it should be
designed to "monitor" with insignificant impact on the load presented
to the transmitter.

You didn't tell us enough to give you a definitive answer, but it is
likely that you are unnecessarily worried about the sensitivity of the
transmitter to VSWR, and the cumulative effect of the monitoring
sensor which should be insignificantly small in the real world with
suitable / practical components.

Owen
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