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# format auto-updated on access: Mon 02-Mar-2026 17:45:57 +00:00 #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 2 March 2026. Front Cover (1) Stuart France installing his latest incarnation of the telemetry box in Dan-yr-Ogof cave in South Wales. Photo: 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 and 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. considers what benefits loop antennas could offer today. Also see the supplement listed immediately below. Comparing Loop and Line Antennas – Online supplement to CREGJ 133 (A1-A2) An induction loop transmitter can operate at a higher current than a grounded electric dipole because the loop has a relatively low resistance when compared to the resistance between two earthed electrodes. However, the magnetic field from a loop falls off more rapidly with distance so it is not straightforward to say that one antenna is better than the other. To compare these two types of antenna system, it is helpful to first distinguish between so-called intrinsic and extrinsic parameters – both are important, but it is the intrinsic parameters that guide a formal comparison of the antenna system. This note, by , is a more detailed version of his box-out in Mike Bedford's article (see above). We Hear (9) 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, and 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, and , 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, 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, 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, provides a summary of what they achieved. Student Projects (23) 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 reports.