[t6dpilot]

Jeff is right. I spoke to a gate agent last night and he said it depends on the agent. He would allow it based on how I described the size and shape. I suspect that if you are up front about what you are carrying, most will not charge you. Or you could just pay for it at home and avoid the $65 at the gate charge. Most airlines are doing that now.

You could try just boarding and see if they say anything, but be prepared to pay for it if they say something. If it is sizable in diameter, then just pay the carry-on fee from home.