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Re: Topband: W8ji ATR-10 design 160M?

To: "topband" <topband@contesting.com>
Subject: Re: Topband: W8ji ATR-10 design 160M?
From: "Paul Christensen" <w9ac@arrl.net>
Date: Sat, 19 Oct 2013 11:44:22 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
"These transmatches these days T matches just do not have the balls for 160M
running power." They do if the tuner's complex load Z is reasonable.> "I melted down a MFJ 998RT arced plates on an MFJ 989B
melted down a 25uH Millen coil, arced wire burned up insulation all with
500 watts :-) I tried different configurations.  Short 99 foot inverted L
does give me a challenge. 0.175 plate spacing arcs over. 0.25 spacing on
caps is needed or vacuums variables which are not in my budget."Give us the complex Z seen at the tuner's terminals on 160m and we can offer up a reason for the behavior. Without knowing the complex Z, it's one big guessing game. In the last five years, complex impedance analzers and vector network analizers have become affordable for most of us and offer superb accuracy when compared to commercial lab-grade instruments. This is definately not directed at you or anyone elase in particular but it's interesting how the general ham population will spring $600-$800 for a wattmeter that offers accuracy they don't need yet won't spend that amount on a complex Z analyzer or used oscilloscope. A fancy wattmeter should be at the tail end of an accessory priority list. > Who makes a tuner that can take this abuse?Tuners that can take a lot of abuse into unreasonable terminating Z are almost all homebrew types using vacuum caps/switches and well-constructed high Q inductors. Paul, W9AC
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