[Elecraft] KX3 and Data modes

[Don Wilhelm]

Ed,

Yes, the most accurate is to use the 'scope with a 10X probe to measure 
the RF voltage across the dummy load.

No need to convert to RMS and all that - use this formula - Power = the 
square of the peak to peak RF voltage divided by 400 if the load is 50 
ohms (8R if other than 50 ohms).  You can substantiate that by formula 
manipulation - the sqrt of 2 terms fall out.

73,
Don W3FPR

On 3/14/2012 3:56 AM, Edward R. Cole wrote:
> There is only one way for me to determine what the accuracy
> is.   That is by observing the waveform across the dummy load with my
> scope, calculating Vrms from the peak-peak voltage and using that to
> determine power using V^2/R, assuming the load is not reactive.  Well
> I might do that out of curiosity.   That is probably the most
> accurate way for most hams to measure power (unless you are very rich
> and own a calorimeter).  I did power measurement at 500-KHz by using
> my scope since I have no elements that work below 2-MHz.  My 100w
> 500-KHz transmitter is equipped with an RF ammeter for
> measuring/monitoring power.
>
>