This is a branch of amateur radio with a very dedicated following. Amateurs launch small balloons with lightweight payloads which are tracked with telemetry on the 70cm band. Some fall back to earth quickly, whereas others manage to cover vast distances. Some payloads include small cameras.
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Recovery is by no means assured so ballooners have to be prepared to lose the lightweight payloads, so they tend to be low in cost as well as light in weight. It has become a sub-set of the hobby with very keen people making some quite amazing payloads. Another group enjoy tracking the ballonns.
Recently, a balloon went all the way from the UK to Japan.