Stratospheric flight lines are attached to a small parachute and a payload. It also attaches the parachute to the balloon. A camera is installed in as one of the payload and the whole unit , including the balloon , is hoisted up.
Lets see the launch of the balloon through a Whimsical animation
Apart from SPOT other trackers can be used to detect the location of balloon.Examples are APRS(Automatic Packet Reporting System), RDF(Radio Dirction Finder), Radioteletype(RTTY), PSK-31(Phase Shift Keying-31 Baud).
Morsecode
Data collected by the balloon is encrypted using morsecode