That basically requires measuring I and Q components from the reflected
power coupler, rather than just magnitude. That, in turn, means
deriving a reasonably accurate quadrature copy of the main transmit
signal. I suspect one of the factors here may be that the tuner has a
wider matching range than the dynamic range of the reflected power sensor.
However, even with the existing hardware, if you are in the dynamic
range of the reflected power coupler, you can work out which constant
SWR circle you are on on the Smith chart, and I suspect that, if you
probed with carefully chosen partial corrections you could probably find
two solutions with one more measurement, and remove the ambiguity with
the third, even using the existing hardware. The third could probably
be based on one of the two solutions.
I'd still suggest the biggest problem is the dynamic range of the
reverse coupler, as, once you have an in range SWR, you can use a
minimum finding algorithm to home in.
Incidentally, if you do need to do a brute force search, using a Gray
code progression will be kinder on the relays than linear sweeps.
Some of this may actually already be being done.
--
David Woolley
On 09/07/2021 00:34, Andy Durbin wrote:
The next generation KAT500 should measure the complex load impedance, including
the sign of X, compute the L and C required to match, and plug in those values
as the initial tuning solution. Why wouldn't this approach be better than
flailing around in the dark like most auto tuners seem to do?
I doubt this will ever happen but the idea of combining the KAT500, LP-100A, and an
Arduino controller to implement this "smart" tuner keeps banging around in my
head. Maybe one day I'll give it a try.
73,
Andy, k3wyc
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
