Roy Lewallen wrote in news:13lr7u2mueltrb3
@corp.supernews.com:

....
Another common directional wattmeter circuit is the Bruene type circuit.
This uses an ordinary current transformer to get the current sample and
a direct connection for the voltage sample. The voltage sample is
reduced to the correct proportional value via a transformer or
capacitive voltage divider. It shouldn't be hard to find a diagram of
one on the web.

The article at http://www.vk1od.net/VSWR/VSWRMeter.htm includes a simple
circuit analysis of the Breune design and some comment on the application
of the instrument.

Owen