sandbox: Journal 133 has gone to press and is due for publication in March 2026
CREG Journal 133 (0-24)
This issue has a cover date of March 2026 and was published on 1 March 2026.

Front Cover (1)
Stuart France installing his latest incarnation of the telemetry box in Dan-yr-Ogof cave in South Wales. Photo: <span class="author">Martyn Farr</span>

Contents (2)
List of contents and masthead information.

News and Notes (2)
Spring 2026 Field Meeting, Hidden Earth 2026, CREG Editorial Team.

Introducing the Nicola 4 Rescue Radio (3-4)
The latest member of the Nicola family of cave radios has recently been released. Developers <span class="author">Graham Naylor</span> and <span class="author">Pete Allwright</span> provide an overview.

Are Cave Radio Loop Antennas Staging a Comeback? (5-8)
In many geographical regions, earth arrays are now used almost universally with through-the-earth cave radios. This is in marked contrast to the early days when loop antennas were invariably used. However, there are indications that there's been a resurgence of interest in loops. <span class="author">Mike Bedford</span> considers what benefits loop antennas could offer today.

We Hear (9)
<span class="author">Mike Bedford</span> reports: iPhone Cave Lidar goes Mainstream, Low-cost Protection for in-Cave Drones, Quantum Physics to Offer an Alternative to GPS?

Pinger 2.0: A New Radiolocation Receiver, Part 1 (10-14)
As a prelude to providing constructional details in a future article, <span class="author">Ken Smith</span> and <span class="author">Aren Leishman</span> provide an overview of the companion receiver to their Pinger 2.0 radiolocation transmitter for use in flooded passages.

Correction (14)
Pinger 2.0: an Updated Transmitter for Radiolocation in Flooded Passages, Part 1, <span class="author">Aren Leishman</span> and <span class="author">Ken Smith</span>, CREGJ 131, pp. 8-10.

PCB Production (15-16)
Affordable PCB production, end-to-end assembly services (PCBA), and large component libraries have made it easier than ever to get high-density surface-mount boards produced for your projects. Using the radiolocation Pinger as an example, <span class="author">Aren Leishman</span> explains how you can use these services yourself in your own KiCAD projects. This article is #11 in our Fundamentals series.

Dan-yr-Ogof Telemetry - Experience and Lessons (17-19)
Previously, <span class="author">Stuart France</span> reviewed a year's progress with his cave water depth and local rainfall data acquisition system and, later, the upgrades made as a result of incidents during the first winter. This concluding article reports that the system is now reasonably reliable, supplying near-live online data on a single clear webpage to cavers about underground cave river conditions that they should expect to encounter.

Overview of University of Nottingham MEng Cave Radio Projects (20-23)
Students at the University of Nottingham have undertaken cave radio-related projects. Here, <span class="author">Tony Haigh</span> provides a summary of what they achieved.

Student Projects (23)
<span class="author">Mike Bedford</span> suggests that cave electronics-based projects for university students would be beneficial to the caving community.

Historical Stereo Cave Photography (24)
3D cave photography has a long heritage as <span class="author">Mike Bedford</span> reports.