At 02:06 PM 8/3/2006, Dan Hearn wrote:
>Additional loss occurs in the tuner which may be greater than xmsn line
>loss. QST has had measured losses for various commercial tuners as the
>subject of 1 or more articles. The losses on low bands and certain
>impedances can be a significant factor. 73, Dan, N5AR
Which is why it's worth playing with something like XLZIZL.. (which
calculates tuner loss)
I also note that the QST reviews don't test into a mismatched *reactive*
load, which, after all, is MUCH more likely than a mismatched resistive
load. That is, you're a heck of a lot more likely to wind up trying to
match 50-100j or 50+100j than 150+0j. And that makes a fairly substantial
difference.
If someone has "good" numbers for the losses of a modern relay style
autotuner (or the Q of the reactive components), I'd love to get them. QST
just did loss checks on manual tuners, and checked the match range for
autotuners into resistive loads.
I've been doing some analysis on just this, and been making sort of WAG
approximations based on the charts in FairRite and Micrometals catalogs.
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