For many years, telephones and wire have been the preferred means of cave rescue communication in North America. Recycled military surplus field telephones are used …

Jul 11, 2018 · The “Heyphone” is a voice radio designed by John Hey, G3TDZ, as open-source hardware specifically for cave rescues. It uses upper (single) sideband voice on 87 kilohertz in …

Jan 31, 2010 · Sixteen-year-old Alexander Kendrick's prize-winning invention combines "teen-tech" with underground communication. His text messaging device could help rescue stranded …

Cave-Link is a data communication and measurement system for cave research and mining. It allows safe data transmission through several hundreds of meters of solid rock. Beside data …

Through-the-Earth (TTE) signalling is a type of radio signalling used in mines and caves that uses low-frequency waves to penetrate dirt and rock, which are opaque to higher-frequency …

Our objective has been to develop a lightweight, mobile, underground radio communica-tions system for use in long and deep cave systems where field phones are difficult to deploy and use.

Feb 10, 2011 · In the US, old military surplus field telephones using two-conductor wire are the basic standard for cave rescue communication. The most recent generation of phones are …

What’s so Special about the HeyPhone? The HeyPhone is a system which provides through-rock communication for use by cave rescue teams. It allows communication between a cave and …

Technically, the HeyPhone is a standard design of single-sideband radio, usually operating at 87kHz USB. In concept, it differs only marginally from Bob Mackin's Molefone, which was used …

Nov 1, 2022 · Hey phone (used in the Thailand cave rescure) was created by an amateur radio guy and apparently there has been some miniaturization and re-designing since then. …