Squeak or buzz at steady speeds

On a long road trip I started experiencing a strange squeaking noise at highway speeds of 75mph. It was intermittent but persistent for perhaps 100 miles or so. Windy conditions made me think it might be side load bearing stress on a wheel bearing. Eventually it quit and it hasn’t returned. I recorded the noise and played it for my mechanic. Without hesitation he said “It’s a vibration in your radio antenna!”. Apparently the combination of driving speed and crosswind conditions caused a vibration in the antenna that resulted in the strange buzzing/squeaking noise. Who would have guessed. Next time I encounter this I will remove the antenna to confirm the diagnosis.

 

I've heard a buzzing noise in mine when going down the highway and there is a 30-40 mph crosswind. It's a pretty rare occurrence though.