Dave Platt wrote:
. . .
As to RF coming out with the cover off - I've always heard that a
well-designed-and-constructed tuner will not radiate a significant
amount of RF even if the case is not a shielded one. Cebik, for
example, writes that "Well-wired ATUs do not radiate, consisting of
passive components only, so a metal case is not required" and
constructed an L-C-L tuner with a case made out of plexiglass.
. . .

I guess we each have our own definition of "significant". Get a small
fluorescent tube. Hold it near one end and wave the other near the tuner
coil. Depending on your power level, tuner setting, and antenna
impedance, the result might spur you to think about the meaning of
"significant".

Roy Lewallen, W7EL