Vertical caving terminology and methods > Personal SRT gear
A wireless (or historically wired) electronic device that can allow communication with others on the same pitch, particularly useful with extremely large pitches, where the length of the hang is so large, or the pitch is so noisy, that even a whistle cannot be reliably heard. This is important to allow cavers to let each other know when they can use the rope, to give instructions to a belayer or winch operator, or to call for help.
Current devices rely on wireless radio signals, and do not rely on external service providers, so they can be used in situations where there are no external phone or radio services, such as in a cave. Since the rock blocks high frequency radio signals used by almost all radio devices, there are not many devices that can work through the rock itself. The dedicated cave radios generally require physical contact with the rock to use it as an antenna, such as a Cave-Link, or a conductor, such as with the single wire earth-return telephone ("France Phone"). This is not useful when hanging on a rope. Two wire telephones can - and have - been used, but this means trailing a wire down the pitch, which will then tangle around everything, and create its own spaghetti. Magnetic induction antennae can send low frequency signals through the rock, but even a small loop antenna is larger than cavers can carry conveniently. As a result, the only viable option is to use regular walkie talkie radios to communicate. These can only be used via line of sight, meaning that the radios must be able to see each other in order to communicate, as the high frequency signals cannot bend around corners very well. It is extremely rare to see these in use with British caving, since the pitches are not normally big enough to need it. However, they might be used by rescue teams, or during expeditions.
As with almost all other caving equipment, designs need to be rugged enough to survive in a cave, with some manufacturers making rugged models designed for remote hiking. They also must have a way of being securely attached, to avoid dropping them, which might be a keeper cord or tether. Rescue teams may use designs with an external speaker and microphone that can be clipped to the shoulder, so that the main device can be tucked away, and only a more easily replaced item placed in a vulnerable position.
This section concentrates on communication systems used for pitches, and does not cover radio systems for caving in general. A "talking machine" telephone is thought to have been used for the first time underground during the 1880 re-exploration of the British Lamb Leer Cavern by miner Andrew Lyons. It is not known whether this was a very early prototype electrical telephone, or a mechanical acoustic telephone (basically a tin can string telephone but with a much better diaphragm). He also carried a revolver, so that he could use it to signal the winch operators if the talking machine failed. This is of course standard vertical caving equipment in some regions, particularly Texas. By 1882, electrical telephones were installed in Oak and Manver's collieries in South Yorkshire, Britain. In 1889, French caver Édouard-Alfred Martel and his cousin Gabriel Gaupillat started using a telephone to communicate with belayers, in the French cave Abime de Rabanel. These were both fairly minimal systems where cavers could just talk to the other telephone user, not part of the regular telephone system. They required a telephone wire. Édouard-Alfred Martel's telephone was just 8 cm in diameter, weighed 480 grams, and could work with up to 400 metres of wire. It was especially useful on pitches of over 100 metres in height. Even though the walkie talkie was invented in 1937, they were still fairly expensive and bulky, until transistors started being more regularly used during the mid 1950s. It was still normal for cavers to use wired telephone cables for big pitches in the 1950s, and wired telephones were used during the British expedition to Grotta di Monte Cucco in Italy in 1969 to communicate on a pitch, and to Ghar Parau in Iran in 1972 to communicate with the surface. It was only during the 1970s and 1980s that walkie talkies would have been commonly available for use by cavers. It is not known when walkie talkies were first used underground, but British caver Sid Perou used them to communicate with assistants while photographing large chambers in the Gouffre de la Pierre-Saint-Martin, in France/Spain, in 1972. British cavers Jerry Wooldridge and Andy Eavis used them to communicate with photographic models Dave Checkley, Martyn Farr and two others in 1984 in Sarawak Chamber, Lubang Nasib Bagus, Gunung Mulu National Park, Sarawak, Malaysia. It is even less obvious when they were first used for vertical caving.
This history section only covers walkie talkies and telephones. This article also has a detailed history of many of the other devices and techniques that are used for vertical caving.
<< Whistle | Bobble, scrunchie, bandana, hair clips >>
This page is not intended to be viewed this way, please load the entire article. This version exists only to make it easier for search engines to understand the contents.