Topband: W8ji ATR-10 design 160M?

[Paul Christensen]

Not sure what happened to the text formatting but let's try this again...

> "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 analyzers and vector 
network analyzers have become affordable for most of us and offer superb 
accuracy
when compared to commercial lab-grade instruments.  This is definitely not 
directed at you or anyone else 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

----- Original Message ----- 
From: "Paul Christensen" <w9ac at arrl.net>
To: "topband" <topband at contesting.com>
Sent: Saturday, October 19, 2013 11:44 AM
Subject: Re: Topband: W8ji ATR-10 design 160M?


>> "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
> _________________
> Topband Reflector