The U.S. National Weather Service sends up a large number of radiosondes attached to balloons twice a day. Their job is to measure conditions at high altitudes up to about 30km. Once the balloon gets too high, the pressure inside bursts the balloon, and a small parachute slows the instrument package’s descent back to Earth. [David] wanted to track these down and return them to the NWS for reuse.
There are several interesting items to note in the post, including a link to a site that tracks ballons all over the world. The radiosondes that [David] wanted to find transmit on 403.4 MHz and they were relatively easy to hear. If you want to join in on the fun, you only need a few simple pieces of gear. One important thing, though, is perhaps the best hack of all: an orange safety vest. As [David] says, “If you’re wearing an orange vest, everyone assumes that whatever you are doing is legit.”