What should be done before climbing a tower that supports electrically powered devices?
Why Rotators, antenna relays, tower lighting and amplifier feed lines on a tower can carry hazardous voltage, so the standard industrial practice of lockout/tagout applies: open the breakers or disconnects feeding those circuits, lock them in the off position, and tag them so no one can restore power while you are aloft. This guarantees the circuits stay dead even if someone else walks by the panel and flips a switch. Verifying the power is off at the tower before you start climbing is part of the same routine.
Watch out Ungrounding the tower base is exactly backward, since the ground connection protects against lightning and fault currents and should never be removed; the electric company has no involvement in your own station wiring.
Lock it out and tag it out before you go up. Never disconnect the ground.