An excellent set of info about tuner networdk Q has come
from Dan, KL7Y. It should be shared by all of you who have
shown so much interest in the nine band, higher power tuner
design problem. Hi comments follow:
>To: jreid@aloha.net (Jim Reid)
>From: Dan Robbins <kl7y@alaska.net>
>It's been a long time since I studied RF networks, but as I remember, the Q
>of an L network is dependent upon the ratio of impedances to be matched. A
>Pi-network can be designed for a range of Q values. I suspect the
>reason for high Q in an antenna tuner on 160 has more to do with the
>inability to chose a large enough coil (in the case of the PI) rather than
>lacking the "low reactance and therefore low Q" of an L match. I own a Nye
>tuner and it seems to work well on the bands it was designed for.
>
>The opposite effect is seen in pi networks in some amps on 10 meters - they
>can't get the input C low enough (because of stray and interelectrode C) to
>obtain a match with a Q of 10 or 12, so they jack the Q sky high which
>enables a match, if the tank doesn't melt down, that is. 160 is at the
>other end, not enough L, so raise the Q to get a match. An L match may be
>the best solution for your case, but it's not a universal cure or those big
>California kilowatts would have L matches in them instead of Pi matches.
>
>Anyway, good luck with your efforts, work some of us KL7's some time!
>
> 73, Dan KL7Y
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