[Antennas] Antenna Tuner

[Robert Lay]

Dear Chris,

Without a thorough examination of the internals, it would be crazy to buy a
used tuner.

Here is a list of things often found in a used tuner:
    Tuning capacitors having grossly asymmetrical spacing between stator
plates and rotor plates.
    Rotary Inductor former that has localized melting and deformation,
accompanied by unevenly spaced or shorted turns, charred former material,
and melted conductor material.
    Geartrain between front panel crank and rotary inductor badly
mis-aligned, pieces missing.
    Rotary switches with badly burned contacts.
    SO-239 female connectors with burned and charred or melted insulation.
    Internal wiring badly modified.
    SWR and/or power monitoring circuitry improperly modified or destroyed.
    Meters burned out.

In case you are thinking that this might be rare, you'd be wrong. By there
very nature, tuners are an anathema to the uneducated ham radio operator.
The tuners that find their way into hamfests and other swap-meets, etc., get
there through misuse.

9 out of 10 tuners that I have purchased have been from other hams and for
the most part they have been basket cases. I quickly learned to remove the
cover and make a thorough examination of a tuner before making an offer. I
have violated that rule on 3 occasions. On two of those occasions I was
badly burned. Fortunately, the money was not a big problem, and I learn from
each such mistake.

Don't be a sucker!

Bob Lay (W9DMK), Dahlgren, VA
w9dmk@crosslink.net
http://www.qsl.net/w9dmk