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# htmlentities() run on access: Sun 01-Mar-2020 11:37:22 +00:00. Delete this line to re-run it. # format auto-updated on access: Sun 01-Mar-2020 11:37:22 +00:00 CREG Journal 109 (0-24) This issue has a cover date of March 2020 and was published on 1 March 2020. Front Cover (1) Kelda Jones in Ogof Ffynnon Ddu streamway, lit using multiple slaved flashes to produce backlight highlights and freeze the water movement, while retaining shadows and contrast in the foreground and caver. Photo: Contents (2) List of contents and masthead information. A Slave to Photography (3-5) looks at the development of photographic slave units before considering the pros and cons of the two main categories used by cavers, namely infrared and radio types. Using QGIS as a Data Hub for Cave Projects (6-10) provides an introduction to this geographical information system, with particular reference to how it is currently used by the Matienzo Caves Project. We Hear (11) Roundup of news and events – brings us the latest to impact the world of cave radio and electronics. Introducing the Caveatron, Drone for Bat Detection, Expedition to Mars Anyone? A Human-powered Torch (12-14) describes the development of the PenduLUME, a prototype human-powered torch, intended for underground backup use when other lights fail. The device is a variation on a Faraday flashlight, using spherical magnets inside a hollow torus to generate electrical power when it is swung like a pendulum. Letters to the Editor (15) Brazen Plug - A Matienzo Cave Project Publication - , Google Earth and Cave Survey Data - . The Adventures of GREG (15) Illustration by , and words by . Building Blocks (16) The humble capacitor has many variants - some considerations in selecting the correct one for the job, by . Spotlight on Google Earth (17-18) Less well-known than Google Maps, argues that Google Earth is a valuable tool for cavers. Here he looks at what’s on offer and gives some guidance on using it in conjunction with free mapping. Building Rugged Equipment for Use in Caves (19-22) In another of our Fundamentals series (#3), describes the problems of building equipment for use in caves. Waterproofing is a big issue, but he also considers the choice of battery and some problems associated with switches and connectors. These notes are aimed at student electronic engineers who might be building equipment for use in caves as a practical element of their degree course. Web Watch (22) offers a couple of links of interest... Wet & Dry (22) reviews an approach for in-cave computing. Project ELF: the US Navy’s Foray into ELF Communication (23-24) delves into the use by the US Navy, with designs dating back to the 1950s, of ELF radio for communication with submarines worldwide.