CREG Journal (ISSN 1361-4800)

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Contents of journal 89
March 2015

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CREG Journal 89 (0-24) (PDF 11.5MB)        Individual articles may be available below

This issue has a cover date of March 2015 and was published on 4 March 2015.

 

Front Cover (1) (PDF 4.5MB)     

Cave diving with OpenROV. Tulum, Mexico 2013. Photo: Fabio Esteban Amador

 

Contents (2) (PDF 240KB)     

List of contents and masthead information.

 

Introducing OpenROV: a Low-cost Vehicle for Remote Underwater Exploration (3-5) (PDF 1.7MB)     

Eric Stackpole introduces a remotely-operated submarine and explains how the open design concept means that it can easily be built by amateur experimenters. In describing how it was designed for a treasure hunt in a flooded cave in California, he illustrates its potential for underwater cave exploration.

 

Understanding and Combating Reverberation in Underground Spaces (6-8) (PDF 451KB)     

Caves, mines and tunnels are particularly reverberant environments. This has a negative effect on the intelligibility of speech and hence the operation of devices such as cave radios. Mike Bedford investigates the severity of the problem and suggests some means by which the impact can be reduced.

 

Web Watch (8) (PDF 228KB)     

Peter Ludwig offers a fascinating selection of links, ranging from useful products, through proposed technologies to items of interesting reading.

 

The SPELEO-GRAPH LB Digital Transmission System for VLF (9-11) (PDF 1.1MB)     

This system, devised by Bernard Lheureux, enables the exchange and recording of SMS-type messages and longer texts through rock. Transmission can take place between the surface and caves, or between caves, over a range of several hundred metres. The simplicity of the hardware design and ease of manufacture has resulted in a lightweight system which is reliable and easy to set up and use. Translation by John Rabson.

 

We Hear (12) (PDF 412KB)     

News and events - Mike Bedford brings us the latest to impact the world of cave radio and electronics, including Laser Surveying Confirms UKs Largest Cave Chamber, Flying Drones get Considerably Smaller, Lynx Caving Lamps, powermonkey explorer 2.

 

Determining the Photographic Guide Number of an LED (13-16) (PDF 385KB)     

White LEDs are increasingly being used as sources of illumination for cave photography, both as modelling lamps and as alternatives to flashguns. Clearly, a simple way to determine the effectiveness of such illumination - the guide number - is to calibrate the light source in a series of practical tests. However, we can also determine the guide number theoretically. David Gibson goes through the steps in this exercise, which brings together several aspects of physics and photometry that the reader may have forgotten. (See CREG forum).

 

FERRA - A New Portable Underground Communication Transceiver (17-19) (PDF 2.1MB)     

Dmitry Fedosov and Dmitry Korneev describe a new radio, intended both for surface and through-rock communication. In a change from most previous designs, the radio operates in the MF region of the spectrum and can be used on-the-go, as a result of its compact design.

 

CREG Summer Field Meeting (19) (PDF 792KB)     

Events have conspired to cause a postponement of the next field meeting until 22nd-23rd August, reports Rob Gill.

 

ZEB1 in Skirwith Cave (20) (PDF 506KB)     

At the recent CREG Field Meeting, the former show cave section of Skirwith Cave in the Yorkshire Dales was surveyed using the ZEB1 handheld laser scanner. Despite the 168m survey being completed in just 36 minutes, unprecedented detail was captured in three dimensions. Data by Emily Williams of GeoSlam Ltd.

 

Letters and Notes (21) (PDF 507KB)     

Alternative Power, Ferrite Antennas, OpenROV.

 

Quantifying Light Quality in White LEDs (22-24) (PDF 997KB)     

To date, much of the discussion of white LEDs in caving circles has concerned luminous efficacy. However, the amount of light that you can obtain from your battery isn't the only important consideration, argues Mike Bedford. Here he investigates the quality of the light which is also important, especially for cave photographers.

 

The Adventures of GREG (24) (PDF 767KB)     

Illustrations by Adrian Higgins with words by Mike Bedford.