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CREG Journal 83 (0-24)
This issue has a cover date of September 2013 and was published on 23 September 2013.

Front Cover (1)
A mines rescue team on an exercise with the m-Comm Mk.2 guidewire communications system. Photo: Golder Associates (UK) Ltd

Contents (2)
List of contents and masthead information.

Newssheet (3)
Diary Dates, Wet & Dry, Radiolocation Equipment, Articles, QR Codes.

Wire-guided Tunnel Communications: the Broader Picture (4-7)
Mike Bedford investigates the basic principles of propagating signals along cave passages or tunnels by use of a guide-wire, and reviews a range of methods applicable to cave communication.

Wi-Fi Performance in Tunnels (7)
Enhanced Wi-Fi performance has been demonstrated in tunnels as Mike Bedford reports.

Amateur VHF and UHF Radios for Caving (8-9)
In a recent article on leaky feeder systems for cave communications it was suggested that handheld radios for VHF and UHF amateur bands should be considered for caving. John Rabson considers equipment for the 144, 430 and 1300MHz amateur bands; other allocations in that part of the spectrum are discussed, as are licensing aspects.

We Hear (10, 14)
News and events - Mike Bedford brings us the latest to impact the world of cave radio and electronics, including eLORAN Expansion, Reinventing the Wheel, Graphene Photo-sensor, New Efficiency Record, Echolocation App, focus on Batteries, Li-ion Goes Spongy, Long Life Li-ion, The Lithium-Sulphur Alternative, Super-capacitors and Virus Batteries.

Surveying Flooded Caves with Neutrally-buoyant Sensors (11-14)
Neutrally-buoyant sensors are designed to ride the current within a flooded underground channel or cave and, using miniature transmitters and receivers, gather information about the shape and morphology of the chamber through which they travel, write Ronald T. Green and Ben Abbott.

m-Comm Mk.2: Guidewire System for Rescue Use (15-18)
Dave Lewis, Roy Tallon and Mustanir Ali describe an underground communication system that uses a wire to guide an LF signal, yet provides freedom to work away from the line thanks to a Bluetooth link.

Web Watch (18)
Peter Ludwig takes another look at the internet and comes up with a few interesting sites. Here's the latest sample.

Wet & Dry (19)
Ruggedisation, waterproofing & constructional techniques. Column edited by Mike Bedford.

The 'Pystol' LED Handheld Water-Cooled Lamp (20)
Andy Lillington presents a further water-cooled LED lamp design, intended for general use and constructed from easily obtained parts.

Rescue Communication in Uncle Sam's Toy Coal Mine (21-22)
Mining coal has always been a hazardous business. Over 100 years ago, the US Bureau of Mines started research into how to provide emergency communications in the event of an accident. John Rabson reports.

Letters to the Editor (23-24)
Batty, Rules of Engagement, Making a Connection.

The Adventures of GREG (24)
Illustrations by Adrian Higgins with words by Mike Bedford.