About 10 years ago, I came up with a simple and inexpensive solution to keep squirrels off of my bird feeder. I purchased an 8-foot length of 6-inch plastic pipe and set it in the ground as far as I could easily dig with a posthole digger (15 to 18 inches). I cut the top to a height I could easily reach (about 6 feet for me), and then I built an 18-by-18-inch platform out of pieces of wood left over from a decking project.
I mounted my traditional feeder to the platform, then mounted the platform to the top of the pole, with three brackets attached to the sides of the pole and to the bottom of the base. I hung a tube feeder from each corner of the base.
Squirrels can’t grip the plastic pole because of its width and slickness, so they can’t climb it. Oh, they tried — and it was hilarious watching them slide down in frustration! One note: Don’t set this feeder near a tree or bush, or squirrels will climb up on it and jump to the feeder.