[Elecraft] My Homebrew Balanced Autotuner

[Don]

Wow!   I have received a lot of responses and there are some very 
interesting and valuable ideas in them.

Wayne's response to the list gets the prize for smoke, mirrors, and just 
plain fun (how much of that is smoke we will never know).  His message set a 
new high for the ratio of reading enjoyment to actual usefulness.

Thanks guys.


p.s.   For those who have asked .... the tuner is a dual L-C network fed 
through an SWR bridge and 1:1 voltage balun and I am using it 160-20M to 
feed a 160M horizontal loop using ladder line.  There is a description of 
the tuner at http:/www.qsl.net/k7fj/ .


Don  K7FJ






>> I bet Wayne knows a good algorithm!
>
> Indeed I do. And it took several weeks of serious R & D and coding the 
> first time we developed an ATU (KAT2).
>
> Among other things, the code uses four tuning phases, each with different 
> granularities; time-based SWR target adjustment; hand-tuned, 
> pseudo-grayscale switching of latching relays; SWR-based look-ahead tree 
> pruning (borrowing extensively from game theory); scaled L-C stepping near 
> local minima; and, when possible, L-C range prediction based on band 
> information.
>
> It was a wonderful, hair-pulling, sleep-depriving, learning experience 
> that I wouldn't deny anyone by giving away the details  ;)
>
> 73,
> Wayne
> N6KR