Some technology may get old, but leave it to radio amateurs to develop important new uses for near-obsolete devices.
The ARRL reports that the use of low-frequency radio equipment developed nearly two decades ago was a key factor in the successful rescue of 12 boys and their coach from an underground cave in Thailand earlier this month. According to the ARRL posting, crews relied on so-called HeyPhones to communicate with each other during the rescue effort. The phones transmit signals on USB at 87 kHz, which is reportedly low enough to penetrate deep into the ground, and the technology remains useful as a communication tool in underground caves.
The ARRL notes that a UK radio amateur named John Hey was the original developer of the eponymously-named device in the early 2000s. However, the use of HeyPhones has declined in recent years as more advanced technologies have been developed.