[TowerTalk] Open Wire

[philk5pc@tyler.net (Phil Clements)]

>You folks are all making me nervous.  Anyone have solid
> knowledge of the Dentron MT-3000A?  I am interested to
> know how it stands up under full power when tuning into a
> 450 commercial line fed 160 or 80m dipole for multiband
> use.  I will be bringing a 1KW+ homebrew solid state amp
> online sometime this winter and do not want the tuner to be
> a source of trouble!
>
The proof of the pudding in store-bought tuners is usually 160 meters.
The two capacitors in the "T" configuration are usually 200-250pf each;
not near enough for the proper L/C ratio on Top Band. This causes you to
switch in more coil (or roll in) to get a reasonable match. Most of the
coils are on the puny side to start with, and a melt-down process begins.
I would never push the so called "legal limit" tuners past the 500 watt level
on 160 meters.

Look at the X-Match" and the 1999 ARRL Handbook cover article to see
how to modify a tuner to play very efficiently with ladder line.

BTW....
The new Radio Shack true rms DVM's come with a temprature probe.
Very useful in finding heating problems in a tuner or tank circuit.


(((73)))
Phil, K5PC




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