I've read a lot of the stuff on lightning protection, including the
famous PolyPhaser technical information, but I haven't found anything
that deals with my (intended) situation.

I am planning to use a random wire connected to an Icom AH-4 tuner
mounted on the chimney at first, later on the tower when it is in place.
I could put a PolyPhaser device in the coax between the tuner and the
shack -- and I could perhaps even get in the habit of disconnecting the
coax where it enters the building -- but what protects the tuner itself?
At the previous QTH the tuner was mounted just below the 2nd-storey
window of the shack, and I could disconnect the antenna wire from the
tuner and clip it to the ground wire (#6) instead. This approach doesn't
work at the new QTH because (a) it's a single-storey house, so the
feedpoint of the wire would be too low, and (b) the basement shack has
no window.

So what are my options? Spark plug? Relay to ground the wire and the
tuner? -- and if so, what kind of relay? Other suggestions?

-=-
Alan AB2OS