[Elecraft] TUNE power, low vs high

[Don Wilhelm]

Arno,

If all things are perfect, there would be no difference.  But in the 
practical, physical world, there are differences.  In the question you 
have posed, there is the wattmeter diodes to consider.  When the forward 
voltage is quite small, as would be the case at lower power levels, 
there may not be enough rectified voltage for a good indication of 
reverse power - that will lead to erroneous results that may cause 
higher SWR indications when the power is increased.

73,
Don W3FPR

On 12/12/2013 7:34 PM, Arno Dienhart wrote:
> What could be the difference for the tuning result between tuning at, say,
> 0.8W vs at 3W?
>
> If there is no difference, why is the ATU tuning set to 2 or 3W, and not
> lower?
>
>