I wasn’t thrilled with how “floppy” even Schedule 80 PVC pipe is, and I didn’t want to put a metal pole on the roof for lightning reasons.
Another solution presented itself at the hardware store: wooden mop/broom handles, which are 15/16th of an inch in diameter. That is very close to the inside diameter of a one-inch nominal Schedule 80 PVC pipe. I had to do a little sanding/shaving to make them fit, but it made the PVC much less bendy.