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CREG Journal 62 (0-28)
Contents

Newssheet (3)
CREG Champions, CREG Web Site, Diary Dates, Back Issue Prices Reduced, HeyPhone PCB Prices.

Development of an FPGA-Based Cave Radio (4-5)
A mid-point progress update by Graham Naylor on his new cave radio design, focusing on an intermediate text messaging system that is phase-locked to an external broadcast reference on 162kHz.

CREG 2004-2005 in Review (6-7)
Richard Rushton provides a review of the last year and David Gibson summarises his financial report

Speleonics (8)
When producing a new design for cave radio/electronic equipment, how do you decide which technology to use? This question produced some interesting responses which John Rabson summarises.

An Introduction to ZigBee (9)
ZigBee is an emerging standard for low power, low data-rate wireless mesh networks utilising small, cheap sensors. Keith Jackson suggests a caving application.

Whither Loran? (10)
The world-wide low frequency navigation system, known as Loran is notorious for its interference with cave radio systems. However, the future of Loran is uncertain, with some beacons closing down. Chris Trayner outlines the current state of play.

Field Meeting Report: Autumn 2005 (11)
A group of CREG members met up in the Yorkshire Dales for our latest field meeting. David Ferguson reports on the weekend's activities.

Low-Power Wireless Mesh Networks in Underground Mining (12-17)
Recent developments in wireless networking technology (e.g. Bluetooth, ZigBee) could lead to a number of applications in the mining industry, with obvious spin-offs for caving usage. In this article Gareth Kennedy describes the use of UHF ISM-band devices in mining, and the evaluation tests that he undertook at the Camborne School of Mines.

HeyPhone Tests in the Sierra de las Nieves (18)
Lino del Campo and colleagues achieved a HeyPhone range of 520m in Triassic limestone. A shale layer proved impenetrable.

Web Watch (18)
Peter Ludwig presents some interesting web sites.

Assessing Noise-Cancelling Headphones Underground (19-20)
Various noise-cancelling headphones were evaluated in an acoustically noisy cave environment. Mike Bedford details the results and gives some guidance for cave radio operators.

Wet and Dry (21)
Chris Trayner looks at a practical problem of earth-wire aerials, checking batteries and more on stainless steel screws.

Directional Microphones for Acoustic Noise Reduction (22-23)
Mike Bedford describes some comparative tests with various microphone directional response patterns in an acoustically noisy cave environment.

Cave Radio Notebook (24)
69: Voltage-Balancing Circuit for 2-Cell Battery Chargers, 70: Two ISB channels on the HeyPhone, 71: Carbon Dioxide Sensors. Edited by David Gibson.

We Hear (25)
A round-up of news from the world of cave-related radio and electronics. Column edited by Mike Bedford.

Letters to the Editor (26-28)
New Ventures for David Gibson, Wireless Video in Caves, Design, Safely Rescued, Workbench Lighting, M3.5 Fasteners, Spanish HeyPhone Update, The Adventures of Greg.