Getting into HF after a looooong time only doing 2m/70cm. Question is what should I ground out my HF rig to in a dug in basement? Copper water main pipe coming in from ground? Steel support pillar bolted to floor? Drive a stake just outside escape window and wire to that? Will the concrete floor provide a solid enough ground if I just lay a copper wire on the floor with a cinder block on it? Can I tap into the ground of an existing GFCI outlet or any other outlet? Thanks.