[Elecraft] High Accuracy Wattmeter

[Charles Greene]

Hi All,

I need a high accuracy wattmeter for reading power from 1 to 10 watts into 
a 50 ohm load with a precision of 0.05 watts or less over the entire 
scale.  I tried a RF probe and a DVM, but the voltage is all over the 
place.  I have a scope, but reading that is like reading a meter.  If I set 
the K2 control, it drifts up pretty much.  Anyone know of any circuits off 
hand that will do this?  How about a DVM connected to my OHR WM1?  I can 
accurately calibrate the voltage reading using a service instrument, but I 
can't use that for the power reading unless the power is going to the 
instrument which it isn't.

TNX for your thoughts.
73, Chas, W1CG