CREG Journal (ISSN 1361-4800)

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Contents of journal 119
September 2022

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CREG Journal 119 (0-20) (PDF 5.0MB)        Individual articles may be available below

This issue has a cover date of September 2022 and was published on 8 October 2022.

 

Front Cover (1) (PDF 1.8MB)     

John T. M. Lyles using the DroidPSK app on a smartphone along with a PSK31 transceiver module, connected to a compact loaded 10MHz dipole. Image: Martin Kavanaugh

 

Contents (2) (PDF 362KB)     

List of contents and masthead information.

 

News and Notes (2)  For download see previous item

Publication Delay, Field Meeting Cancelled, Rob Gill.

 

Stereo Micro-Photography Using Focus Stacking (3-7) (PDF 1.2MB)     

The depth of field of an image decreases as the subject reproduction ratio increases. As a result, it becomes very shallow at high magnifications, as is the case in macro-photography and, even worse, in micro-photography. It is therefore difficult to obtain optimal sharpness over the whole subject, even with small apertures. Daniel Chailloux explains how the 'focus stacking' technique uses software to combine a set of images to restore sharpness. He illustrates it with some stereo pairs of micro-mineral samples, photographed by André Marent. Contributions also from Roger Huet and Béatrice Serre.

 

We Hear (8) (PDF 424KB)     

Roundup of news and events: Mike Bedford brings us the latest to impact the world of cave radio and electronics. Gamma Ray Measurement, Ultimate Cave Surveying Instrument, The Magna Doodle as a Caving Notepad?

 

First Impressions of a Home-made 3D Laser Scanner (9-11) (PDF 1015KB)     

Encouraged by building and using the Caveatron cave surveying and handheld 3D laser scanning tool, Ian Cooper turned his hand to designing a tripod-mounted scanner. While not yet a ready-to-go project, the results are impressive, as illustrated here.

 

The Mobile Ultraphone and Capacitive Coupler Options (12-14) (PDF 580KB)     

Following his recent introduction to the Ultraphone, a new single-wire telephone for very long-range operation under suboptimal conditions, Brian Pease describes a portable version together with construction details that offers a way of coupling to the line without making a direct electrical connection.

 

Building Blocks (15-16) (PDF 361KB)     

Pros and cons of using licence-exempt RF spectrum, by Tony Haigh.

 

Power Line Interference in Baseband and VLF Cave Communication (17-19) (PDF 409KB)     

With some cave communication experimenters turning their attention from LF to VLF, and even audio frequencies, the subject of interference from high voltage mains distribution could become an issue. Here, Mike Bedford discusses the problem and outlines some methods of mitigation.

 

Position Encoder Uses Single-Track Gray Code: Update (19) (PDF 227KB)     

This is an update to David Gibson's article in Journal 118 where he described an unusual single-track position encoder that encoded absolute position using a Gray code.

 

Poster-Sized Stereo Photos: Update (20) (PDF 343KB)     

David Gibson makes some further comments about viewing poster-sized stereo photos and asks for feedback on how other people manage with this technique.