[Amps] Re: [Amps] Bird. 43 Manual

[Peter Chadwick]

Another way of analysing it is an AC bridge.

But as Tom (and others) have said, without the capacitive coupling, it doesn't
work - at least, not as a wattmeter.

A point was made about directivity. Somewhat off the subject, the problem with
impedance measurements using directional coupler techniques (such as a network
analyser) is that when the impedance is a long way from 50 ohms or whatever the
design impedance is, the accuracy really goes for a chop. That's because a
largish change in impedance produces a relatively small change in return loss.
So don't believe that a network analyser is necessarily accurate at high SWRs!

73

Peter G3RZP