On the advice of Adrian Marsh, I modded my 3kw antenna tuner.
Basically I needed a way to bypass all of the tuning elements on one of the outputs to make it easier to tune Tesla Coils with it. By adding a vacuum relay I am able to use one of the pushbuttons on the front panel to enable/disable this feature.
I used a vacuum relay because of the power level; a normal relay could arc over at high power level and cause ‘issues’.
The blue wire is connected to the vacuum relay, and the white and red wires lead from it to the normal + bypassed modes.
So far so good; everything works good, looks authentic, and the only changes needed to the chassis were re-soldering a couple wires. The whole thing could be reverted to ‘normal’ in less than an hour if I ever wanted.