Hi Gary,

I like the topic of discussion. I've been working with the AD633's for
several years now. I'm wondering why you vered away from the V*I idea.
That would make your calculation good for any load. Instantaneous V
times instantaneous I will give the answer whatever the relative phase
happens to be. Maybe I'm missing something?

Hi Jim, this didn't show up on my ng reader for some reason, hope you don't
mind me replying on the ng.
The reason I didn't the V*I route, which as you say, is the obvious way to
go: I did not feel I could get accurate V and I samples over a wide range of
RF frequencies, with my limited knowledge and resources. I thought a simple
resistive voltage divider would make it real simple, and somewhat frequency
independent. I am now finding through the responses I have gotten, that
resistors will be frequency dependent as well. Darn.
I recently tried to use 633s in an application at 60hz to detect when a very
large generator went from producing power (generator) to absorbing power
(motor). I found that the potential and current transformers I was using
introduced an unacceptable phase shift from primary to secondary. I tried
several different types but finally took another approach. This is probably
another reason that steered me away from the V*I solution.
If you have a simple way to get accurate V and I samples for say 3-30MHZ I am
all ears, and forever in your debt.
73 Gary N4AST