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CREG Journal
Contents. (This is a bit-map scan).

Some Experiments in Speech Bandwidth Reduction
John and Hugo Rabson describe their progress with speech bandwidth reduction in software.

The D-Q Beacon Receiver - Overview
Brian Pease outlines the receiver for use with the radio-location beacon described in the last issue.

Caving Electronic Projects at University
The CREG is keen for university students to work on cave radio projects. Chris Trayner looks at what's already been done and the way forward.

Emergency Caving Lamp Uses LEDs
Mike Bedford presents a simple constructional project.

An Introduction to Data Transmission
An introduction to data communications as applied to cave radio, by David Gibson.

Closed Circuit TV for Underground Use
A circuit for transmitting video signals over cheap twisted pair cable is described by Nick Negus.

The Talking Machine of Lamb Leer Cavern
Bob Williams describes the re-discovery of Lamb Leer Cavern in the 1880s. This includes the first recorded use of a telephone in cave exploration.

Cave Radio Notebook
10: skin depth, 11: speech band compression, 12: toroidal loop antennas, 13: the inverse cube law, 14: data communications.

An Optimal NiCd Charger
Mike Bedford outlines an intelligent charger based on the principle of 'optimal charging'. A flow diagram is given.

Spectral Optimisation of a Loop Antenna Driver
Derek Potter investigates whether it is possible to match the antenna tuning to the signal spectrum in order to maximise the output.

Electronics in Surveying, part 2
David Gibson elaborates on his article in the previous Journal. Global positioning and inertial navigation are discussed.