Also live near the data centers. While I'm obviously not 100% sure, I think that blue one is on Glenn Dr - for a bit of context, that is less than 3 miles (drive) from the Dulles International Airport. I'll see if I can record a video of the sound later tonight.

https://www.google.com/maps/place/38%C2%B059'57.6%22N+77%C2%...