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CREG Journal 102 (0-24)
This issue has a cover date of June 2018 and was published on 1 June 2018.

Front Cover (1)
Peter Eggleston describes his implementation of Brian Pease’s DQ-Receiver design to Les Williams and Tony Haigh at the recent CREG Field Meeting. Photo: Ian Cooper.

Contents (2)
List of contents and masthead information. CREG Field Meeting Dates, Hidden Earth.

LoRaWAN and its Application to Cave Data Logging (3-4)
LoRaWAN, an up-and-coming licence-free standard for wide-area networking, is becoming a key enabler of the Internet of Things. Mike Bedford introduces the technology with particular attention to its role in cave-related data logging.

The Hidden Earth Timetable Display (5-7)
The UK’s annual caving conference – Hidden Earth – has experimented with a network of computers that provide timetable displays, as well as news and information. The latest iteration uses a Raspberry Pi computer at the heart of each ‘information point’, which operates a web browser, pulling information from a local web server. The software and hardware are being developed by David Gibson, a member of the Hidden Earth organising team, who here outlines the salient points.

Setting up the Micro HeyPhone (8-10)
In the last part of Ian Cooper’s introductory series of articles on the Micro HeyPhone cave radio, Ian provides practical details for those intent on building the new radio. In particular, this follow-up article considers firmware programming, fault finding, tuning and alignment and using the radio.

Letters to the Editor (10)
Cave Radio Standards (Ron Taylor), Online Resources (John Rabson).

Web Watch (10)
The intrepid Peter Ludwig uncovers some more internet gems in his search for fascinating and diverting items.

Wet & Dry (11)
Ruggedisation, waterproofing & construction techniques – a roundup by Tony Haigh. Glue: Sticking Things Together.

SMD Construction at Home (12-14)
Ian Cooper describes the method he has developed for hand soldering SMD components. It is expected that this will give amateurs the confidence to undertake SMD construction at home as required, for example, to build the Micro HeyPhone.

Signal-to-Noise Ratio and Cave-to-Surface Communications (15-16)
In the first of our new occasional Fundamentals series, Chris Trayner investigates signal-to-noise ratio with a view to explaining why a cave radio downlink is often more reliable than the uplink.

Early Development of Guidewire Radio Underground (17-18)
John Rabson unveils 1920s radio experiments aimed at empowering rescuers following serious mining incidents such as explosions and fires. Recent wire-guided radio equipment for mines rescue, and the leaky feeder systems used in transport tunnels, have built on this pioneering work.

We Hear... (19)
News and events – Mike Bedford brings us the latest to impact the world of cave radio and electronics. Multi-sensor Geophysical Cave Detection in Bulgaria, Organic LED Break-through Promises Lighting Applications, Tuneable White LEDs, Flexible Batteries for Wearable Electronics.

CREG Field Meeting: Shropshire, May 2018 (20-21)
Snailbeach Mine in Shropshire was the location of a recent well-attended get together. Robin Gape reports on the weekend’s activities that ranged from radio tests of various types through radio-location to bat detection and photography.

Automated Speech Intelligibility Testing with the ABC-MRT (22-24)
Quantitatively assessing speech intelligibility commonly requires a panel of listeners to score speech samples. This is a time consuming and tedious activity and there are potential difficulties in recruiting volunteers. Rob Gill has been examining the Articulation Band Correlation Modified Rhyme Test, which offers an alternative.