Depending on the attachment method (spikes and ferrules or hangers) either way, you can ziptie a insulator on them and run a wire thru
them and create a dipole, feed point at your option. Been there, done it, got the tshirt. Another option somewhat trickier is to obtain a expansion
joint, on long runs the steel or aluminum gutter and will shrink or expand so said joint is a must. The gutter is cut, joint is installed and now it
becomes a dipole. However word of warning your downspouts are hot when key down also they must not touch the ground, once again have the
shirt The first way was effective as I drilled a hole and fish taped the coax thru the eve sealed it well and went down thru a wall and to a tuner,
worked very well. second method was on a long ranch house and it too worked well. Just be sure water doesn't pool up any where near the joint.